Technology Handbook 2006

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Technology Handbook

Technology Handbookfor Service Engineers

Edition 2006

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Technology Handbook

I. INTRODUCTION

This handbook has been prepared to help service engineers better understand the functions of the differentmachines in the Rieter line, the impact of fibres on the machine performance, the relationship between thefunctions of different machines and the effects of the machines condition and the surrounding environment onprocessing performance and product quality.

The chapters relating to the machines cover:- the principle features as presented by sales personnel to the customer.- start up guidelines to help meet both the production and technological expectations of the customer,- operational optimization,- trouble shooting guidelines,

- interpretation of evenness tester diagrams and spectrograms,- the impact of preceding processes on subsequent machines,- general information regarding optional components for some machines and their applications,- machine settings for various fibres and production rates, and- suggestions regarding the handling of machines for optimal efficiency.

In the spinning plant every operation has to be optimized to produce a product of the required quality, withconsistent characteristics at high levels of productivity. Quite often certain parameters such as raw material, yarntype for different end uses, machine components and production rates are changed. With each change there is aneed to make the necessary adjustments to maintain a successful operation.Care has to be taken to ensure that, what appears to be, a very good setting at one process can have a negativeimpact on a subsequent process. For example, a Drawframe can be set with close cylinder settings to produce asliver with a very low evenness CV%, but it may be that there is some “over control” of the fibres. This can lead toan increase in spinning ends down and a loss of yarn strength. The impact of any change has to be checkedthrough to the end product.

In some instances it is necessary to adjust the downstream machines in order to obtain the full benefits of anoptimized preparation process. This particularly applies to roving and ring spinning. If the new sliver has a higherlevel of fibre orientation than previously, the roving twist and/or the draft distribution may need to be changed.

Hopefully the contents of this manual will help in the understanding of the relationships between the manyaspects of yarn production and how they affect the machine efficiency and the end product.

Administrative editor in charge: Markus Peter

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Technology Handbook

1. Fibres and Classification

I. FIBRES USED IN SHORT STAPLE SPINNING 3

I. Fibre groups 3

1. NATURAL FIBRES 4

1.1. Cotton 4 1.1.1. Fineness 4 1.1.2. Fibre maturity 5 1.1.3. Fibre length 6

1.1.4.

Fibre strength 7

1.1.4.1. Pressley – psi 7

1.1.4.2. Stelometer 1/8″ gauge – g/tex 7 1.1.5. Fibre elongation 8 1.1.6. Impurities 8 1.1.7. Technical terms relating to cotton 9 1.1.8. Ginning 10 1.1.8.1. Roller ginning 10 1.1.8.2. Saw ginning 10

2. SYNTHETIC OR MAN-MADE FIBRE GROUPS 11

2.1. Introduction 11 2.1.1. Man-Made Fibres - Overview 12

3. CLASSIFICATION OF YARN COUNT / STAPLE LENGTH 14

3.1. Classification of yarn counts (Cotton) 14 3.1.1. Classification of cotton staple to yarn count assignment 14

3.2. Yarn count assignment (Man-Made) 18

4. PROCESSING CHARACTERISTICS MAN-MADE 22

4.1. Polyester Fibre 22

4.2. Micro Polyester Fibre Processing 23 4.2.1. Choice of raw material and experimental plan 24

4.3. Processing characteristics in the fibre preparation 26 4.3.1. Blowroom and Card 26 4.3.2. Drawframe 27 4.3.3. Roving frame 28 4.3.4. Yarn Spinning Process 28 4.3.5. Yarn evenness 30 4.3.6. Yarn Imperfection 31 4.3.7. Yarn strength and elongation 35 4.3.8. Hairiness and abrasion 36

4.3.9.

Yarn resistance against mechanical influence 38

4.3.10. Conclusion 40

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4.4. Processing characteristics of Tencel® LF micro fibres on high-performance machinery 41



Technology Handbook

4.4.1. Properties of cellulose fibres 41 4.4.1.1. Advantages of micro fibres 41

4.4.2. New machine technologies 42 4.4.3. Processing study 45 4.4.3.1. Results raw material 45 4.4.3.2. Results ring yarn 48 4.4.3.3. Results in rotor yarn 51 4.4.3.4. Yarn structure 53 4.4.3.5. Downstream processing 54 4.4.3.6. Summary 56

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Technology Handbook

I. Fibres used in Short Staple Spinning

The cost of fibres used in the production of yarn accounts for approx. 50% of the production costs. Consequently,the skilful selection and use of the raw materials has a great impact on the success of a spinning plant. Thecorrect setting of machines is, to a large extent, dependent upon the fibres being processed. A thoroughknowledge of fibres and their properties is essential for the spinner.

Fibres fall into one of two groups, natural fibres such as cotton, flax and wool, and the man made fibres such aspolyester, viscose/rayon, nylon, acrylic and polypropylene. Each fibre type has its special characteristics thatmake it perform differently from other types.

Fibre properties directly influence the end products in the following ways:- strength- yarn count- productivity- uniformity- fabric hand- lustre- drape- absorbency / comfort- easy care properties

Some of the distinguishing features of the different fibres are given in the following sections.

I. Fibre groups

There are two main groups of fibres used in short staple spinning.- Natural fibres- Man made, or manufactured fibres

In the natural group, cotton is the predominant fibre, followed by flax. Of course there are many other naturalfibres, but they are of lesser interest to the staple spinning industry.In the manufactured fibre group, polyesters, rayon’s and acrylics are the main sources for staple spinning.

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Technology Handbook

1. Natural Fibres

1.1. Cotton

There are approximately 80 countries throughout the world that produce cotton. Many use the fibre locally but themajority sells some fibres on the world market. The growing conditions of each region can have a significanteffect upon the variation of fibre properties, the cleanliness, neppiness, stickiness and the contamination. Aspinner’s change from one source to another can have a dramatic effect on a plant’s efficiency.

The 10 main growing regions are listed in descending order of production:

1 United Stated of America 6 Turkey

2 China 7 Australia3 India 8 Argentine4 Pakistan 9 Egypt5 Uzbekistan 10 Greece

1.1.1. Fineness

The fineness of cotton is frequently the most important fibre property, particularly for ring spun yarns. Fine yarnspinning is limited to the number of fibres in the cross-section, which is proportional to the fibre fineness.

Spinning-Limit: Yarn cross section

Number of fibres = tex-yarn / tex-fibre

Long staple (wool & blends) = 40 fibres

M-made 3.3dtex 50 –60 -80mm = 55 fibres

M-made 1.3-1.7 dtex/ 38 -40mm = 70 fibres

Cotton Ring yarn (min. 40) = 70 fibres

Cotton Rotor yarn = 100 fibres

Also, the higher the number of fibres in the cross-section, the more uniform the yarn can be. Yarn strength isincreased and weak places reduced with finer fibre and subsequently downstream processing efficiencies can beimproved.

The cotton fibre is not normally circular in crosssection and cannot be defined by its diameter.

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Technology Handbook

Micronaire is widely used to indicate fineness. This value is obtained by measuring the airflow through a plug ofcotton. The finer the cotton, the lower is the airflow and the lower is the micronaire value.

On the other hand, man made fibres can be categorized by weight/unit length i.e. decigram/km =dtex.

The following is a scale of micronaire values and fineness equivalents:

Scale Micronaire dtex(Mic x 0.394)*

Denier

very fine up to 3.1 up to 1.22 up to 1.35

fine 3.2 - 3.9 1.26 - 1.54 1.39 - 1.70

average 4.0 - 4.9 1.58 - 1.93 1.74 - 2.12

coarse 5.0 - 5.9 1.97 - 2.32 2.17 - 2.55

very coarse 6.0 and above 2.4 and above 2.64 and above

*The conversion value for micronaire to dtex is dependent upon fibre maturity and is only to be used with thisunderstanding as an indicator of fineness.

1.1.2. Fibre maturity

All cotton contains mature fibres and immature fibres. The degree to which the fibre has developed its wallthickness determines the degree of maturity. Those fibres with very low levels of maturity, i.e. very thin walls aresometimes called dead fibres or unripe fibres and do not take dye in the normal way. Additionally these fibres areusually of lower strength.

Immature fibres lead to:- white spots in dyed fabrics- variations in dye shade- neppiness- fibre fly due to fibre breakage, andprocessing difficulties at the card.Frequently, cotton containing an excessive amount of immature fibre is discounted in price because of thepotential problems it can cause.

Fibre maturity has traditionally been measured by the Causticaire process in which the fibres are swollen in acaustic soda solution. The wall or “lumen” is then judged to be mature or not.

Maturity index = fibre fineness before Causticaire treatment x 100fibre fineness after Causticaire treatment

Instrumentation such as the IIC – Shirley fineness/maturity tester and also equipment using near – Infrared (NIR)techniques have been developed to obtain an indication of fibre maturity. These are being extensively used toreplace the sensitive and time consuming Causticaire procedure.

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Technology Handbook

Maturity standards

Causticaire maturity index HVI, IIC maturity ratio

82% to 100% mature above 1.0 very mature76% to 81% medium maturity 0.8 to 1.0 mature

71% to 75% immature 0.7 to 0.8 immature

below 71% very immature below 0.7 uncommon

1.1.3. Fibre length

The length of cotton is not an absolute measurement. Any sample of cotton taken from a bale, or taken duringpreparation for spinning, will have a similar fibre length distribution with long fibres and with short fibres, which

have been broken during the mechanical operations - see the illustration below.

Cotton staple diagram showing the different important measuring Points.

The USTER® AFIS instrument measures each fibre separately and, therefore, all information for an end-alignedstaple diagram is available. The illustration depicts various benchmarks, such as «Upper Quartile Length» (UQL)and the short fibre content.The UQL is the fibre length at 25%. The term «upper quartile» indicates that the value is calculated in the upperquarter of the staple diagram.

The staple length (classer’s length) of the fibre is a primary feature in establishing the price of the cotton. Longerstaple is more expensive. In spinning plants the fibre length ( 2.5% ) is needed to correctly set the machineswhere fibres are controlled in nip zones, i.e. at the feed plate of the card and in the setting of the draft zones inthe drawing processes and in spinning.

In the spinning plant the fibre length has a direct influence on the:- yarn strength and evenness- spinning limit and ends down rate- production speeds and machine efficiency

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Technology Handbook

Additionally the presence of short fibres, less than 1/2″ or 12.5 mm have a negative influence in that they:- are uncontrolled in the drafting process creating uneven yarn

- create excessive fly around the machines- are lost or removed as waste, which is a processing cost increase and- create fly and lint in the downstream operations.

In general the staple length referred to in the plant is the “classer’s” staple, which can be grouped into thefollowing categories:

Category Staple length

Extra long staple 1 13/32″ and longer

Long staple 1 5/32″ to 1 3/8″

Medium staple 1 1/32″ to 1 1/8

″ Short staple 1″ or less

Rotor spinning is not sensitive to short fibre content and can effectively handle short fibre in the spinning ofcoarse and medium count yarns.

Ring spinning, Airjet and Vortex systems using high draft apron systems for medium and fine yarn counts needlonger staple and greatly benefit from the removal of short fibre via the combing process to produce fine counthigh quality yarns.

1.1.4. Fibre strength

1.1.4.1. Pressley – psi

The two sets of clamps holding the fibres touch each other with virtually zero length between the clamps. Theclamps move to break the fibre with what is called a "zero length gauge”. The resulting force to break the fibrebundle is used to calculate the Pressley (psi) value. Cotton strength ranges from below 70 psi, which is weak, andabove 100 psi, which is very strong.

1.1.4.2. Stelometer 1/8

gauge – g/tex

The two sets of clamps holding the fibres are separated by 1/8″ prior to breaking the fibre bundle. The strength iscalculated to give g/tex and additionally the fibre elongation can be determined.The use of High Volume Instrument testing has increased the use and acceptance of this technique.Cotton strength g/tex can vary from 15 g/tex for very weak cotton to 30 g/tex and above for very strong cotton.Cotton strength is important because it is the primary component in determining the yarn and fabric strength. Additionally, a consistently stronger yarn can frequently be produced at higher speeds, which is important inminimizing conversion costs.

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Technology Handbook

1.1.5. Fibre elongation

The combined effect of fibre strength and fibre elongation determines the way a fibre will withstand “work”.Elongation is very important in that it enables all the fibres to share in contributing to yarn strength. Higherelongation is preferred if it is available.Cotton fibres range from 5.0% elongation, which is very low to 7.6% elongation, which is high.

1.1.6. Impurities

Baled cotton contains many contaminations, which include:- cotton plant material and remains of weeds,- sand and dust from the fields and dust carried by the wind, and

- foreign matter such as metal, bale wrapping material, plastic bags blown into the cotton fields and fabricdropped by field workers and fibre handlers.

In processing cotton it is necessary to use metal separators to prevent damage and fires.

Foreign matter such as plastic, fabrics and coloured fibres are removed either manually or with equipmentdesigned to detect and remove “off coloured” material.

The amount of vegetable matter, sand and dust in the cotton is referred to as “trash” and can vary from region toregion. Some typical trash contents are as follows:

Trash class Trash content Example

very clean 0 - 1.2% i.e. El Paso Pimaclean 1.2 - 2.0% i.e. Peru Pima

average 2.0 - 4.0% i.e. Texas and Uganda

dirty 4.0 - 7.0% i.e. Pakistan

very dirty 7.0% and above i.e. Southern Brazil

The extensive use of HVI testing has led to additional standards relating to trash being accepted and used as partof the cotton grading system.

Non-lint content of American upland cotton

Classer’s grade Grade code Leaf code HVI trashreading

Shirley analyzernon-lint content

Strict middling 21 2 01 2.0%

Middling 31 3 02 2.7%

Strict low middling 41 4 03-04 3.3%

Low middling 51 5 05-08 4.0%

Strict good ordinary 61 6 09-12 5.2%

Good ordinary 71 7 13-18

One of the major challenges of the spinning plant is to remove the trash and minimize the amount of fibre lost inthe process. This theme will be covered in later chapters.

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Technology Handbook

1.1.7. Technical terms relating to cotton

Lint Cotton fibre produced at the gin after the seed has been removed.

Linters Very short fibres removed from the seeds after the ginning process. Short fibres remain on the

seed when the normal fibre is removed. Linters are relatively clean but less than 1/4″ long. Theyare not normally used in the spinning plant but go into the production of cellulose, acetate andrayon.

Gin motes Fibres reclaimed from the waste removed from the cotton at the gin. They are usually very dirty,discoloured, neppy and high in short fibre content. They are used in non-woven and some “lowend” coarse yarns

Hid Bales compressed into a smaller “High Density” condition to reduce space for overseas

transportation.

Rain growncotton

Cotton produced under conditions of natural rainfall. Care has to be taken when using cotton fromdifferent regions because uncontrolled mixing can cause shade variations in the finished fabric.

Irrigatedcotton

Cotton grown under irrigated conditions. Frequently rain does not fall on the cotton plant in itsmature state. (USA in Arizona, California and other very dry regions)

Cotton colour Cotton colour is influenced by:- the growing conditions – rain, wind and dust,- Contamination by undesirable vegetable matter grown in the cotton field,

- Storage conditions in the field or in the bale,- Cotton is graded by its colour from best to worst as:Good colour – Tinged – Spotted - Yellow Stained – Gray

Moisturecontent

The amount water contained in the cotton fibre. The toughness of the fibre is greater when itcontains more moisture. However excessive moisture will lead to mildew during storage orchoking in processing. A commercial standard of 8.5% moisture content for cotton has beenestablished.

Spindlepicked

Cotton that has been mechanically harvested using rotating spindles to pluck the opened cottonbolls from the plant. Only a relatively small amount of plant material is removed with the cotton.However, it is possible to create entangled fibres and neps if the spindles are not in good

condition or are not operated correctly.

Strippedcotton

Cotton that has been mechanically harvested using the “stripping” technique, in which thecomplete plant, except for the main stem and a few branches, is removed with the cotton bolls.The gin has then to first separate the plant material and sand from the seed cotton before theginning process.

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Technology Handbook

1.1.8. Ginning

Ginning is the process of removing the cotton-fibre from the cottonseed. Usually there is a preliminary cleaningoperation to remove the most of the plant material prior to ginning.

1.1.8.1. Roller ginning

In roller ginning the cotton fibres are clamped between rollers and pulled away from the seed. Trash is notfragmented in the process. Consequently the cleaning operation in the spinning mill is relatively easy. Rollerginning is frequently preferred for long and extra long staple cotton, most of which is spindle picked rather thanstripper harvested.

1.1.8.2. Saw ginning

The saw gin removes the fibre from the seed by using a cylinder covered with “saw tooth” wire. The teeth hookthe fibre and pull the seed against a grid. Saw ginning is an intensive, high production operation and care has tobe taken at the gin to correctly maintain the condition of the equipment. After the fibre has been removed from the seed, the fibre is passed through one or more lint cleaners, whichremove additional trash before the cotton is baled.

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Technology Handbook

2. Synthetic or Man-Made fibre groups

2.1. Introduction

The statistics of the last years point to a constant rise of worldwide chemical fibre production. The worldwideproduction of chemical staple-fibres and filaments lies already higher than those of the natural fibres, with aproduction relationship of 57% to 43%. The chemical fibre production data does not correspond with theconsumption data in the spinning mills, because the production numbers also contain the quantities for the fleece-, filler- and technical applications.

Cellulosics

Filament

1%

Synthetics

Staple

37%

Cellulosics

Staple

7%

Synthetics

Filament

55%

Production man made fibers 2004Total 36 496 000 Tons

Quelle CIRFS 2005

The largest chemical fibre producer is China (32%), followed with a large distance is Europe (11%), Taiwan, theUSA (9,5%), the ASEAN countries (8%), Korea, India and Japan.The market concentration is in China/Asia, Europe and the USA, whereby the quantitative production of over 50%by China/Asia, is significant.

The polyester staple fibre - with a world production of approx. 8.6 million tons - attains China the largest

production (approx. 34%), followed by smaller manufacturers from ASEAN countries (approx. 11%), Taiwan andthe USA (9,5%), Korea, Europe and India (each 6.5%).

The acryl fibre, with a substantially smaller world production of 2,8 million tons, is predominantly manufactured inEurope with a quantity of approx. 31%. The volumes produced in China and Japan are average, the USA andKorea (approx. 4.5% with enormous increase), Taiwan, India and ASEAN countries manufacture only smallquantities.

The cellulose fibres such as Viscose (Rayon), Modal, and Lyocell are in the world production with 2,2 million tonssimilar to acryl fibre. Also here is China the leading producer with approx. 34%, followed by Europe, ASEANcountries and India with average productions. Taiwan, the USA and Japan manufacture smaller quantities.It emerges that China is a powerful chemical fibre producer with rising production, in particular from polyester and

acrylic fibres. Europe is a top producer of cellulose fibres.

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The polyester fibre has the strongest representation in the spinning mill, followed by acrylic and cellulose fibres assecond, however with a large distance.

Staple fiber production worldwide

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

22000

24000

26000

28000

1989 1991 1993 1995 1997 1999 2001 2003 2005

Years

P r o d u c t i o n [ 1 0 0 0 t o n s ]

Cotton Synthetics Cellulosic WoolQuelle CIRFS 2005

The reason primarily given is that the cotton production cannot simply be increased at will because of the limitedarea of cultivation and the yield per square unit. The equalizer to the increasing fibre demand must thereforeinevitably be made by means of the chemical fibre production from natural and synthetic Polymers

2.1.1. Man-Made Fibres - Overview

In the following overview are the chemical fibres, also known as Man-Made Fibres "MMF", divided into the threemost common groups. The fibres from the groups "natural polymers" and "synthetic polymers" are well knownfibre types in spinning mills. The fibres in the group "Bio polymers", are for the moment still exotic and scarcelyrepresented.

Micro fibres are identified as, fine fibres with a fineness < 1.1 dtex. This represents however a higher number offibres in the ribbon and with the same fineness of the ribbon, a higher tenacity. This at the other hand can lead todrafting problems, i.e. the ribbon size must be reduced.

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Overview of Man-Made Fibres used in spinning mills

Viscose (CV) 23..30 cN/tex Polyester (PES) 50..71 cN/tex Nature Works (PL

- Rayon (term in Asia, USA)

Polyacryl (PAC) 24..35 cN/tex

- Modal 32..38 cN/tex high bulk yarns --> s liver count has

modified Viscose to be adapted to the voluminous fibres

- Micromodal Polyamide (PA) 39..70 cN/tex

sam e as Modal -> fibre < 1,1 dtex

PA-Aramide Nomex 40..55 cN/tex

- Lyocell (CLY) 39..50 cN/tex Kevlar 250..300 cN/tex

- Tencel Polypropylene (PP) 28..55 cN/tex

Polyvinylchloride (PVC) 22..33 cN/tex

Micro fibres --> Fibre fineness < 1,1 dtex -> higher number of fibres in cross section for higher y

high tenacity fibres --> fibres with higher tenacity (~ + 5..10%)

low-pilling fibres --> reduced fiber tenacity ( -15..25%) -> red. Yarn tenacity -> red. Spindle speed ->shiny fibres --> tendency to higher fiber-fiber friction -> higher cohesion -> slightly higher drafting

half de-lustered, de-lustered fibres --> reduced service-life of spinning elements / slightly reduced drafting strength

flame-retardant fibres --> chlorine fibres -> danger of corrosion

extruded- /tuft dyed fibres --> tendency to higher aggression then raw-white fibres -> reduced speeds

Man Made Fibres "MMF"

Bio Polysynthetic Polymer

synthetic MMF natural Polymer

cellulose MMF

F i b r e s p e c i f i c

a t i o n

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3. Classification of yarn count / staple length

3.1. Classification of yarn counts (Cotton)

The finness of the yarn counts is divided into four classes, similar to the raw material. The classification of theyarn counts serves the standardized use of lingo.

The following table shows the classification of yarn counts for spinning mills.

Yarn count Yarn count range Cotton class

Ne Nm tex staple length

coarse 3...16 5...27 197...37 short

medium 17...44 28...76 34,7...13,1 medium

fine 45...80 78...135 12,8...7,4 long

very fine > 80 > 135 < 7,4 extra long

Applicable to the ring spinning and rotor spinning process.

3.1.1. Classification of cotton staple to yarn count assignment

The respective staple lengths were assigned according to the finest possible yarn counts and separated intocarded or combed process. In addition, the yarn counts are grouped into classes.Within the finer count ranges, some staple lengths classes are overlapping, to achieve a meaningful and praxisrelated classification.

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The rotor yarns are predominantly spun from carded cotton. This application allows for use of even shorterclasses compared to ring yarns. Combed middle staple cotton is used as raw material upgrade or for yarn quality

improvement in certain end uses of rotor yarns.

Cotton staple / Yarn count assignment Rotor yarn

Released R40: Ne 3. ..60 Date: Jan. 2003

Cotton Staple length Range Yarn count Yarn count

staple length

class Inch in mm in mm Ne Nm tex Ne Nm tex

29/32" 23.02 22.8 bis 23.5

short 15/16" 23.81 23.6 bis 24.3

31/32" 24.61 24.4 bis 25.1 < 12 < 20 > 49

1" 25.40 25.2 bis 25.9 < 16 < 27 > 37

1 1/32" 26.19 26.0 bis 26.7

1 1/16" 26.99 26.8 bis 27.5

medium 1 3/32" 27.78 27.6 bis 28.3

1 1/8" 28.58 28.4 bis 29.1

1 5/32" 29.37 29.2 bis 29.9

1 3/16" 30.16 30.0 bis 30.7

1 7/32" 30.96 30.8 bis 31.5

long 1 1/4" 31.75 31.6 bis 32.2

1 9/32" 32.54 32.3 bis 33.0

1 5/16" 33.34 33.1 bis 33.8

1 11/32" 34.13 33.9 bis 34.6

1 3/8" 34.93 34.7 bis 35.4

R a w m a t e r i a l " u p g r a d e "

q u a l i t y i m p r o v e m e n t

e n d u s e

< 40 < 68 > 14,8

< 60 < 102 > 9,8

P r o c e s s

P r o c e s s

< 10 < 17 > 59

c a r d e d

c o m b e d

c o m b e d

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The ring yarn guidelines are valid for the “normal” and compact yarn range. Please note; for compact yarns,cotton with a staple length of 1 1/16” and up and yarn counts finer then Ne 10 are spun.

Cotton staple / Yarn count assignment

Released G33: Ne 5,5*...160 ( * Ne 5,5..12 -> depending on number of spindles) Date: Jan. 2003K44: Ne 10...160 ( K44 -> Staple > 1 1/16")

Cotton Staple length Range Yarn count Yarn count

staple length

class Inch mm in mm Ne Nm tex Ne Nm tex

29/32" 23.02 22.8 bis 23.5

short 15/16" 23.81 23.6 bis 24.3

31/32" 24.61 24.4 bis 25.1

1" 25.40 25.2 bis 25.9 < 18 < 30 > 32,8

1 1/32" 26.19 26.0 bis 26.7 < 24 < 40 > 24,5

1 1/16" 26.99 26.8 bis 27.5

medium 1 3/32" 27.78 27.6 bis 28.3

1 1/8" 28.58 28.4 bis 29.1

1 5/32" 29.37 29.2 bis 29.9

1 3/16" 30.16 30.0 bis 30.7

1 7/32" 30.96 30.8 bis 31.5

long 1 1/4" 31.7531.6 bis 32.2

1 9/32" 32.54 32.3 bis 33.0

1 5/16" 33.34 33.1 bis 33.8

1 11/32" 34.13 33.9 bis 34.6

1 3/8" 34.93 34.7 bis 35.4

1 13/32" 35.72 35.5 bis 36.2

extra 1 7/16" 36.51 36.3 bis 37.0

lng 1 15/32" 37.31 37.1 bis 37.8

1 1/2" 38.10 37.9 bis 38.6

1 17/32" 38.89 38.7 bis 39.4

1 9/16" 39.69 39.5 bis 40.2

1 19/32" 40.48 40.3 bis 41.0

1 5/8" 41.28 41.1 bis 42.4

1 11/16" 42.86 42.5 bis 44.0

1 3/4" 44.45 44.1 bis 45.5

< 160 < 270 > 3,7

< 100 < 170 > 5,9

< 120 < 203 > 4,9

< 65 < 110 > 9,1

< 80 < 135 > 7,4

< 40 < 68 > 14,8

< 40 < 68 > 14,8 < 45 < 76 > 13,1

P r o c e s s

P r o c e s s

< 36 < 60 > 16,4

c a r d e d

c o m b e d

c o m b

e d

Ring yarn

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MB3537f.xls/01.03-PT

Yarn count range in function to staple length

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

5 10 12 16 20 24 30 36 40 50 60 70 80 100 120 140 160

Yarn count Ne

S t a p l e l e n g t h m m

carded combed

s h o r t

m e d i u m

l o n g

e x t r a l o n g

Ring yarn combed and carded cotton

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Technology Handbook

3.2. Yarn count assignment (Man-Made)

The spinning limits depend on the fibre fineness and the minimum number of fibres in yarn cross-sectionnecessary. To achieve a trouble free spinning stability and an acceptable yarn break level, a minimum of 70 fibresshould be present in the yarn cross section. With long fibres or Micro fibres this number may be decreased.

When establishing a spinning plan, a variety of limits must be considered:

- Drawframe: whenever possible apply eightfold doubling and two processes, whereby the latter should be auto-levelled;the fibre ribbon should not exceed the number of 27'000 fibres, when entering the main draft of theRoving frame;when blended with combed cotton, the MMF-part should be pre-drafted separately;

- Roving: the total draft at the Roving frame should ideally be in the range of 7.5. . .10 fold;the MMF fibres with a cut staple 38. .40 mm (50 mm) must be drafted at the Roving frame with themiddle cradle (45 mm);the roving count must be selected in such a way, that the roving ribbon does not contain more then4300 fibres, otherwise drafting disturbances in the Ring spinning drafting system can occur;

- Ring spin: with MMF the total draft on the Ring spinning frame should - depending of the yarn count – be

between 27. .60-fold, however with the coarsest counts this can not be kept;the Viscose fibres are susceptible to high drafts and may be drafted only up to max. 45. .50-fold;to achieve a trouble free drafting performance, fibres with a cut-length of 38. .40 mm should beprocessed with the 43 mm cradle;

The three following graphs contain the yarn spinning limits as well as the yarn count range depending of the fibrefineness and staple length.

H. Schwippl 17.11.06 18/56



Technology Handbook

Chemical fibre --> Yarn count assignment Date: June 05

Released: G33: Ne 5,5*...160 K44: Staple cut-leng

* Ne 5,5..12 -> depending on number of spindles K44: Ne 30...80

Fibre Staple cut-length Number of fibres

fineness in yarn

dtex mm Inch cross-section

3,3 60 2,5 " > 64

63,5 mm

2,2 50 2 " > 71

51 mm

1,7 50..51 2 " > 77

51 mm

1,7 38..40 1,5 " > 77

38 mm

1,3 38..40 1,5 " > 67

38 mm

0,9 / 1,0 38 1,5 " > 66 / 59

38 mm

P r o c e s s

P r o c e s s

R i n

g s p i n n i n g c o n v e n t i o n a l G 3 3

R

i n g s p i n n i n g " C o m f o r " K 4 4

Rin

Yarn count Yar

Ne Nm tex Ne

< 28 < 48 > 21 Not

< 38 < 65 > 15,5 30..38 5

< 45 < 77 > 13 30..45 5

< 45 < 77 > 13 30..45 5

< 68 < 115 > 8,7 30..68 5

< 100 < 170 > 5,9 36..80 6




Technology Handbook


Chemical fibre --> approx. Yarn count range

1

2

3

4

5

6

5.5 10 12 16 20 24 30 36 40 50 60 70 80 100 12

Yarn count [ Ne ]

C h e m i c a l f i b r e d a t a

[ d t e x / m m ]

conventional Comfor K44

3 , 3

d t e x

6 0

m m

Ring spinning yarns --> conventional and Comfor

2 , 2 d t e x

5 1 m m

1 , 7 d t e x

4 0 m m

0 , 9 / 1 , 0 d t e x

3 8 m m

1 , 3 d t e x

4 0 m m



Technology Handbook


Ideal drafting range for the Chemical fibre spinning process

depending on the fibre fineness, Roving- and yarn count

0.5

0.60.7

0.8

0.9

1

1.1

1.2

1.3

1.4

1.5

1.6

1.71.8

1.9

2

2.1

2.2

2.3

2.4

2.5

2.6

2.7

2.8

5.5 10 16 20 24 30 36 40 50 60 70 80 1

Yarn count [ Ne ] K44 --> Ne 30..80

R o v i n g c o u n t [

N e ]

Yarn count range by 3,3dtex / 60mm

Yarn count range by 2,2 dtex / 50 mm

Yarn count range by 1,0 dtex / 32-40 mm

Ideal drafting range

Yarn count range by 1,3dtex / 34-40 mm

Yarn count range by 1,7dtex / 40mm



Technology Handbook

4. Processing characteristics Man-Made

4.1. Polyester Fibre

The most versatile and widely used fibre is polyester where the maximum number of variations in terms ofphysical, chemical and geometric properties are possible as compared to other synthetic fibres. Over the yearsthere has been tremendous development of polyester fibre and today it occupies the largest market shareamongst all synthetic fibres.

The technical production of Polyester fibres already began in 1945. Polyester is manufactured from crude oil asthe output raw material, the substances dicarbon acid or oxycarbon acids and ethylenglycol are won throughheating process. For the various types of Polyester, the output materials differ in their exact chemicalcomposition. The chemical reaction resp. compound of the molecules takes place under splitting of water. Theprocess is also described as polycondensation. The Polyester is a glassy resin. Next to a multitude of technicalarticles, the raw material is highly suitable for the textile garment sector. In this connection, the Polyester ismelted at a temperature of 280 deg. Celsius and then further processed to filament or staple fibres.

The fibre fineness ranges here from 0.6 dtex to 6.6 dtex. Today, the classic cotton-spinning mill handles fibrefineness from 0.9 dtex – 3.3 dtex with fibre lengths up to 60 mm.

Polyester fibre generally distinguishes itself by the following advantages;

High melting point

High breaking strength not only in a dry but in a wet conditionHigh elongation Abrasion resistantHigh UV resistantResistant to organic and mineral acidsCrease - resistant in textile fabricNo shrinkage and feltingGood dimensional stabilityEasy to wash

The characteristics of the raw material, compounded with a suitable fibre construction such as:

- Fibre count (micro fibre)- ideal combination to fibre length- shape of cross-section (round, trilobal etc.)- bicomponents

can produce an excellent textile fabric with specific textile characteristics. These textile characteristics, such asthe area optic, when compared to those produced from natural fibres, exhibit hardly any differences or withspecial fibre constructions, are even superior. Thanks to micro fibre, characteristics can be created which, forinstance, correspond to the advantages of natural silk.

H. Schwippl 17.11.06 22/56



Technology Handbook

4.2. Micro Polyester Fibre Processing

While the proportion of micro staple fibres in 1991 was merely approx. 3,000 – 4,000 tons per year, today thewhole micro staple fibre production of all raw materials amounts to approx. 600,000 tons per year.

Spinning yarns from micro fibres facilitates greater yarn strength in rotor spinning as well as good runningcharacteristics and ability to produce finer yarns thanks to a higher number of fibres in the yarn cross-section.

The following study was carried out to observe the processing performance of micro fibres in Ring spinning. Aswell known, today ring spinning can be subdivided into the conventional and compact technology. On the groundsof the unique production technology, Rieter offers compact spinning on the market under the registeredtrademark “COM4®”.

Advantages and areas of use of micro fibres are as follows:

Spin-ability:

Spinning finer yarns

Application:

Sport sector for waterproof, airproof and breathable clothingLow weight fabric with same functionalityOuterwear

Characteristics in textile fabric:

Silky appearanceSilky drapePleasantly soft to touchBetter lustre due to more uniform.

The following study refers to a micro fibre of 0.9 dtex with a cutting length of 40 mm. In particular with spinning ofmicro fibres and high cutting lengths, the “pliability of the fibre” is an important criteria. The relationship of the fibrelength to the fibre diameter is also described as slimness degree. The fibre diameter can be determined fromround cross-sections as follows:

h

md

××

×=

π δ

2

m

h

= Fibre mass [g]

= Related length [mm]

δ = Fibre density [g/cm ^3 ]

With a fibre density of 1.38 g/cm3, a slimness degree results of approx. 4400. Such a high slimness degreenecessitates very careful and gentle settings in the spinning process in order to counteract the tendency of fibreentanglement and formation of neps.

H. Schwippl 17.11.06 23/56



Technology Handbook

In addition, the drafting forces in the spinning process are strongly determined by the number of fibres in thecross-section. With the use of micro fibres, there are more fibres in relation to a cross-section than with fibres

which have a conventional fibre fineness like 1.2, 1.4 deniers. The drafting forces again have substantialinfluence on the size of production at the individual process levels in the spinning process, in particular with theCard.

For the production of fine yarns, micro fibres offer a particular advantage for good spinning performance. A yarncount of approx. 7.4 tex and a fibre fineness of 0.9 dtex gives with approx. 80 fibres in the cross-section asufficient number of fibres for a stable running behaviour, whereby the spinning boundaries for ring yarns are stillnot reached.

The Recron TM micro fibres exhibit a round cross-section. The fibre – fibre and fibre – metal friction and staticgeneration are fundamentally determined by the spin finish and influences the processing characteristics andfinally the yarn quality in the staple fibre-spinning mill.

The amount of the spin finish and its composition is a primary parameter for the friction and static conditions. Thespin finish amount should remain constant across the individual process levels. Spin finish deposits within thespinning process interfere with this and can also have negative effects on the spinning ability and yarn quality. Todetermine the amount of spin finish, the spin finish can be extracted from the fibres by using Methanol and theamount in relation to the fibre weight can thereby be determined.

4.2.1. Choice of raw material and experimental plan

An increasing trend towards textile end-products made of micro fibres such as Polyester is becoming apparent.RecronTM Micro fibres give a silky gloss and soft touch in textile knitting and weaving products. It has tenacity of6.8 – 7.0 gpd, elongation of 22 – 24 % and very low level of fibre shrinkage.

As final spinning system, compact and conventional ring spinning were chosen on the grounds of their yarn countand length. The choice of raw materials was made according to the raw material trends.

Raw material Fibre countdtex (den)

Fibre lengthmm

Polymer type Spinning system

Polyester 0.9 (0.81) 40 Semi dull Ring conventional andcompact

H. Schwippl 17.11.06 24/56



Technology Handbook

The following high-performance Rieter spinning machines are used:

1 UNIfloc A 102. Blending Opener B 3/33. Feed Chute A704. Card C 51 Hi – per5. Pre-Drawframe SB – D106. Finisher RSB – D307. Flyer F 108. Ring Spinning Frame G 339. ComforSpin® - K 44

Spinning plan for ring spinning when using micro fibres to achieve best quality is varied as follows:

Machine Type Feeding in[tex]

Doubl. Draft[

Run out[tex]

Delivery[m/min][U/min][kg/h]

Card C 51 4200 20 - 40

Pre-Drawframe D 10 4200 6 – 8.4 6.3 3000 + 4000 300 - 500

Drawframe RSBD 30

3000 + 4000 6 6.0 3000 + 4000 300 - 500

Flyer F 10 3000 + 4000 1 7.5 - 7.54 400 + 530 1200 mα 17 + 19.7

Ringconventionaland COM4®

G 33K 44

400 + 530 1 40 + 53 10 16500 1080 T/m + 10% lesstwisting with COM4®


G 33K 44

400 + 530 1 48 + 63 8.4 16000 1178 T/m + 10% lesstwisting with COM4®


G 30K44

400 + 530 1 54 + 72 7.4 15500 1255 T/m+ 10% lesstwisting with COM4®

H. Schwippl 17.11.06 25/56



Technology Handbook

4.3. Processing characteristics in the fibre preparation

4.3.1. Blowroom and Card

One opening stage has been used, although depending on the Polyester type, up to two openings could benecessary. For a technologically expedient fibre preparation, adjustments of the technological elements and thesettings are also necessary if the production speed of the card is increased. With regard to the wire for fibreopening on the card, over the years the needle rollers on the Rieter Card C 51 have proved very effective inrelation to quality and quality constancy. For the whole trial range, a needle roller with 36 points / 2 inch and aneedle angle of 58 deg. was used as licker-in on the Card.

In order to keep the carding force as low as possible, a cylinder wire as typically used today of 640 points and 30deg. working angle was at this stage applied for micro fibres. The beginnings of the processing of micro fibres on

the card showed in the 90’s the application of even finer cylinder wires, such as 1080 points per sq. inch. Withtime, however, it became apparent that in practice disadvantages often resulted.

The efforts to achieve a highest possible quality by higher point numbers or to keep the number of fibres in thetooth gaps constant against the coarser fibres led to excessive card force. The fibres could only reach the toothgaps with difficulty because of the high fibre metal friction. This caused the card force to massively rise without anoptimal carding being achieved.

A wire, which is too coarse, on the other hand, can tend to overload. Due to a higher number of fibres betweenthe teeth, in the extreme case the fibres can no longer be delivered from the cylinder wire. Added to this is thatwith the low single-fibre mass of micro fibres, the centrifugal force on the cylinder is no longer suffices for thedelivery, as the centrifugal force reduces linear to the fibre mass.

Consequently, with fibre counts from 0.9 dtex top figuresbetween 640 and 720 per sq. inch and 25 - 30 deg. workingangle have proved successful. The optimal wire dependsalso on the fibre characteristics, the spin finish and theclimatic conditions.

Setting parameter Card production 40 kg/h

Needle licker - inU/min

1430

CylinderU/min

400

Cylinder wire GrafR-2530x0.6 CS

720 Points30 deg. working angle

Flat wire GrafPT 43 / 0

Doffer wire M 5030 x 0.9 R340 points

30 deg working angle

The use of 640 points shows with this raw material that thefibres do not allow an optimal delivery from the cylinder tothe doffer. It was observed that the relatively fine fibre

became fixed in the wire grooves. A higher cylinderrevolution to achieve a higher centrifugal force was notchosen for reasons of a lowest possible fibre stress.

Therefore, the number of points on the cylinder underotherwise equal conditions was increased to 720 points persq. inch.The running characteristics and the fleece quality were subsequently to be described as very good.

In the fibre strength, the stress of the fibre appears clearly in the carding process. The fibre strength decreases

within this process by approx. 8 cN/tex. The reduction in fibre elongation amounts approx. 4%.

H. Schwippl 17.11.06 26/56



Technology Handbook

The climate showed following reaction:

Temperature Relative Humidity Reaction

23 deg. Celsius 58 % Poor fibre guidance on the fibre guidance and leadingelements due to fibre splitting.

25 deg. Celsius 68 % Adhesion of the fibres on the fibre guidance and leadingelements, in particular on the chute feed.

23 deg. Celsius 62 % Very good running performance

The card wire and climatic conditions certainly have a great influence on the optimal card forces and the quality.In order to substantially increase the card production with micro fibres, new methods such as the reduction of thefibre volume by increase of the carding working area must be realised. That means the conventionally workingwidth of 1 m must be clearly increased.

4.3.2. Drawframe

To determine the processing characteristics, the drafting force in the main drafting field on the first and seconddrawing passage was measured. The values relate to the respective optimal machine settings and thereforemerely relate to the feeding fibre mass. The whole drafting level of the draw frame lay respectively in a scale from6 – 6.3 fold. To obtain a comparison of the drafting force with micro fibres, two further fibre types of Polyesterwere used.

Based on the chosen fibre measurements, no excessively high drafting forces are exhibited with micro fibres. Thedrafting forces are here on both drawing passages with 14 to 25 much smaller than in comparison to the twoconventional fibre counts and fibre measurements. Under the assumption that the drafting force can play adecisive role for an even drafting, the feeding fibre mass in the drafting arrangement could also with Reliancemicro fibres quite easily amount to minimum 27 dtex. In further investigations in the area of the draftingdevelopment with the processing of micro fibres, it must still be clarified, however, whether the middle draftingforce for an even drafting or the diffusion of the drafting force is the dominating factor.

0

5

10

15

20

25

30

35

4045

50

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Feeding fiber mass [g/m]

D r a f t i n g f o r c e [ c N ]

PES 0.9 dtex 40 mmsemi dull

Pre-drawframe

PES 1.3 dtex 32 mm

bright whitePre-drawframe

PES 1.3 dtex 32 mm

Dope dyed blackPre-drawframe

Drafting force in main draft zone on the Pre-drawframe

Recron TM

H. Schwippl 17.11.06 27/56



Technology Handbook

0

5

10

15

20

25

30

35

40

4550

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Feeding fiber mass [g/m]

D r a f t i n g f o r c e [ c N ]

PES 0.9 dtex 40 mmsemi dullFinisher

PES 1.3 dtex 32 mmbright whiteFinisher

PES 1.3 dtex 32 mmDope dyed blackFinisher

Drafting force in main draft zone on the Finisher

Recron TM

4.3.3. Roving frame

With a feed count of 4000 tex and 3000 tex, an appropriate general drafting occurs at 7.5 fold.

The twist transmission from the spindle in the spinning triangle is an important criterion on the Roving frame.Despite optimal roving twist of 19.7 (530 tex, 27 T/m) for the following ring spinning machine drafting

arrangement, attention must be paid to a good twist transmission from the spindle in the spinning triangle on theflyer. The twist must thereby be optimally transmitted from the spindle to the spinning triangle and may not showperiodically any untwisted places between the flyer crown and delivery cylinder

mα

The twist transmission is strongly influenced by the fibre – metal friction of the particular raw material resp. itsspin finish. To this point attention must be paid with the processing of micro fibres.

A good twist transmission is achieved by the following points:Flyer quality which causes little fibre – metal friction

suitable Flyer attachment crownssuitable climatic conditions

The best climatic conditions for the Flyer could be established at approx. 23 deg. Celsius and a relative humidityof approx. 50%.

4.3.4. Yarn Spinning Process

As final spinning machine the conventional ring spinning system and the compact system COM4® were taken.The spinning positions are compiled in the following overview:

Yarn type Machine type Description Twist

Ring K 44 COM4® mα 108

Ring K 44 COM4® mα 97

Ring G 33 conventional mα 108

H. Schwippl 17.11.06 28/56



Technology Handbook

In order to show the influence of both final spinning methods as clearly as possible, a most gentle fibrepreparation resp. card performance of 30 kg/h and under consideration of stable running characteristics on the

Ring spinning frame and spindle speeds between 15’500 and 16’500 rpm with a ring diameter of 38 mm wereselected.

15000

15500

16000

16500

17000

7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0

Yarn count [tex]

S p i n d l e r o t a t i o n a l s p e e d [ U / m i n

Com4am 108

Com4am 97

Conventionalam 108

Spindle Speed over the Yarn Counts

Reliance Polyester 0.9 dtex 40 mm, Ring 38 mm

According to yarn structure and yarn count, influence parameters of the spinning process play a stronger orweaker role in the measurable quality criteria of the yarn. The yarn quality values achieved are, on the one handsubstantially influenced by the yarn structure and yarn count, on the other hand the influence of the fibre

preparation varies according to yarn structure and yarn count. To obtain an optical impression of the various yarnstructures, the yarn body with a yarn count of 10 tex is magnified 50 times.

H. Schwippl 17.11.06 29/56



Technology Handbook

4.3.5. Yarn evenness

On the COM4® system a better evenness of absolute 0.3 to 0.8 percentage points according to the capacitivemeasurement is given depending on the yarn count of both roving variations. Thereby, it is already apparent thatalso with Polyester micro fibres the fibre compaction has a positive influence on the fibre orientation. The yarntwist reduction from 108 to 97 on the compact system shows no negative influence on the evenness.mα mα

The roving count 530 tex mα 19.7 shows, against those with 400 tex mα 17, a worsening of 0.4 percent

primarily with conventional ring spinning systems and fine final spinning. This means that according to the finalspinning system with approx. 6000 fibres in the cross-section in combination with a 19, slight quality losses

are already to be reckoned with. Consequently, in the case of highest quality requirements, the number of fibresin the cross-section or the twist factor must be reduced. The tendencies are confirmed by the variation coefficientof the yarn diameter on the optical measuring module of the UT 4.

mα

13

13.5

14

14.5

15

15.5

16

16.5

17

6 7 8 9 10 11

Yarn count tex [g/1000m]

C V m [ % ]

9

10

11

12

13

14

15

16

17

C V 2 D [ % ]

Com4am 108capacity CVm


Conventionalam 108capacity CVm

Com4am 108optical CV2D


Conventionalam 108optical CV2D

Yarn evenness

Reliance Polyester 0.9 dtex 40 mm, Roving 400 tex

13

13.5

14

14.5

15

15.5

16

16.5

17

6 7 8 9 10 11


C V m [ % ]

9

10

11

12

13

14

15

16

17

C V 2 D [ % ]



Conventionalam 108capacity CVm




Yarn evenness


13

13.5

14

14.5

15

15.5

16

16.5

17

6 7 8 9 10 11


9

10

11

12

13

14

15

16

17

C V 2 D [ % ]

Com4am 108capacitive CVm


Conventionalam 108capacitive CVm




Yarn evenness


13

13.5

14

14.5

15

15.5

16

16.5

17

6 7 8 9 10 11


9

10

11

12

13

14

15

16

17

C V 2 D [ % ]



Conventionalam 108capacitive CVm




Yarn evenness


% ] % ]

[ [

C V m

C V m

H. Schwippl 17.11.06 30/56



Technology Handbook

The optical evenness, in addition to the capacitive evenness, makes the influence of the yarn twist visible. Areduction of the yarn twist factor from 108 to 97 results in a minimally higher variation of the yarn

diameter resp. the optical yarn evenness of approx. 0.2 percent.

mα mα

An improvement in the evenness of COM4® yarn is attributed to the improved fibre bonding on the spinningtriangle. A better bonding of the outer fibres in the yarn core favourably affects the evenness, even with this rawmaterial. Further, the improved evenness shows a positive effect on the IPI values through a better fibre bonding.Missing or less bonded fibres in the yarn body lead to higher thin and thick place values. In the extreme case,sporadically or inadequately bonded fibres “short thick places” also exhibit more neps in the yarn.

The differences in the yarn evenness with the same fibre sample between both spinning systems is therefore notfounded in an improved drafting performance from one to the other ring spinning machine drafting system or thedrafting performance on the final spinning machine but in an improved fibre bonding in the spinning triangleresulting from the compaction.

Due to the aerodynamic compaction of the fibres on the perforated cylinder, the spinning triangle is reduced to aminimum.

Operating Principle

4.3.6. Yarn Imperfection

As expected, the thin places in the yarn were reduced due to the compact spinning system COM4®. On bothrovings, according to the yarn count and taking into consideration the distribution, approx. 8% - 20% fewer thinplaces resulted. This result can be explained, as also mentioned with the evenness, by a better fibre bonding inthe spinning triangle. Here, the evenness as well as the IPI values have a direct correlation.

H. Schwippl 17.11.06 31/56



Technology Handbook

Roving with much lower drafting force of approx. max 760 cN (400 tex + mα 17) also results in a reduction of up

to 20% of the thin place values in comparison to roving with a higher drafting force of approx. max 1650 cN (530

tex + 19.7). To achieve lowest thin place values, the fibre number should next be reduced from 6000 fibresin the cross-section or the twist factor of 19.7 somewhat lowered.

mα mα

It can be recorded that the quality influence in this yarn count area, at least with the roving composition, turns outequally as big as by the final spinning systems. This means the negative influence of the roving can besuperimposed by the positive influence of the final spinning system.

0

100

200

300

400

500

600

700

800

6 7 8 9 10 11


T h i n p l a c e s - 4 0 % [ p e r 1 0 0 0 m

]

Com4

am 108

Com4

am 97

Conventional

am 108

Yarn Thin Places


0100

200

300

400

500

600

700

800

6 7 8 9 10 11


Com4

am 108

Com4

am 97

Conventional

am 108

Yarn Thin Places


0 m ]

1 0 0

[ p e r

0 %

a c e s - 4

l

T h i n p

H. Schwippl 17.11.06 32/56



Technology Handbook

In the thick places, clearly improved values of up to 20% as with conventional ring yarn also result from theCOM4® system. Further, with the production of the COM4® with the coarser roving (drafting power max. 1650 cN

with 530 tex + 19.7) as compared to the “softer roving” , no negative influence can be registered on the thickplaces.

mα

This means that the conventional spinning system reacts more sensitively to the roving characteristics with theprocessing of micro fibres than the COM4® system. The conventional ring yarn under the application of the “softerroving” has at least 10% fewer thick places. From this can be deduced that to achieve lowest values on theconventional spinning system, the number of fibres of 6000 fibres in the cross-section or the twist factor of

19.7 must be somewhat reduced.

mα

0

20

40

60

80

100

120

140

160

180

200

6 7 8 9 10 11


T h i c k p l a c e s + 5 0 % [ p e r 1 0 0 0 m ]

Com4am 108

Com4am 97

Conventionalam 108

Yarn Thick Places


0

20

40

6080

100

120

140

160

180

200

6 7 8 9 10 11


Com4

am 108

Com4

am 97

Conventional

am 108

Yarn Thick Places


]

1 0 0 0 m

p e r

5 0 % [

s +

a c e

c k p l

T h i

H. Schwippl 17.11.06 33/56



Technology Handbook

Between the spinning systems, no differences in the neps are apparent taking into account the distribution.Thanks to the coarser roving of 530 tex, the nep values were even better than those with the soft roving. The

greater roving mass results in a higher draft on the Ring-spinning machine, which positively affects the number ofneps.

0

15

30

45

60

75

90

105

120

135

150

6 7 8 9 10 11


N e p s + 2 0 0 % [ p e r 1 0 0 0 m ]

Com4am 108

Com4am 97

Conventionalam 108

Yarn Neps


0

15

30

45

60

75

90

105

120

135

150

6 7 8 9 10 11


Com4

am 108

Com4

am 97

Conventional

am 108

Yarn Neps


]

1 0 0 0 m

p e r

% [

2 0 0

e p s +

N

H. Schwippl 17.11.06 34/56



Technology Handbook

4.3.7. Yarn strength and elongation

Despite the relatively high yarn strength which occurs from a greater number of fibres in the yarn cross-sectionwhen processing micro fibres in comparison to coarser yarn count with the same yarn count, a strength increaseof approx. 1 cN/tex of the particular yarn counts through the better fibre bonding on the COM4® system is,however, apparent. The elongation here is inevitably reduced due to the high strength values. The elongationdifference between the two spinning systems can thereby be explained that by a very good fibre alignment andfibre bonding in the yarn thread, the fibres can assimilate fewer length changes in the fibre formation.

A lowering of the yarn twist by 10% on the COM4® shows no reduction of the average strength. With regard to theaverage strength, the twist factor of 108 to 97 could therefore be lowered which equals a production

increase of the final spinning machine.

mα mα

On the conventional ring spinning system, a strength increase of approx. 0.7 cN/tex from the coarser roving (530

tex + mα 19.7) to the very soft roving (400 tex + mα 17) could be recorded. With the COM4® System, thestrength increase which results from the softer roving lies at approx. 0.5 cN/tex.It can be seen that the yarn strength and elongation when using micro fibres already reacts negatively to therespective roving characteristics of 530 tex, however can be still described as satisfactory.

20212223242526272829303132333435

6 7 8 9 10 11


S t r e n g t h [ c N / t e x ]

88.258.58.7599.259.59.751010.2510.510.751111.2511.511.75

E l o n g a t i o n [ % ]

Com4

am 108

strength

Com4

am 97

strength

Conventional

am 108

strength

Com4

am 108

elongation

Com4

am 97

elongation

Conventional

am 108

elongation

Yarn Strength and Elongation Tensojet


202122232425262728293031323334

35

6 7 8 9 10 11

Yarn countt tex [g/1000m]

S t r e n g t h [ c N / t e x ]

88.258.58.7599.259.59.751010.2510.510.751111.2511.5

11.75


Com4

am 108

strength

Com4

am 97

strength

Conventional

am 108

strength

Com4

am 108

elongation

Com4

am 97

elongation

Conventional

am 108

elongation

Yarn Strength and Elongation Tensojet


H. Schwippl 17.11.06 35/56



Technology Handbook

4.3.8. Hairiness and abrasion

The low hairiness resulting with the COM4® system is clearly effective with Reliance micro polyester compared tothe conventional ring spinning system, measured according to Uster UT and Zweigle 1 + 2 mm. With increasingyarn numbers, the differences are smaller but are still obviously lower on the COM4® depending on the yarncount as when compared to conventional yarn. The coarser roving with 530 tex has a clearly negative influenceon yarn hairiness.

2.5

2.65

2.8

2.95

3.1

3.25

3.4

3.55

3.7

3.85

4

6 7 8 9 10 11


H a i r i n e s s U T

0

10

20

30

40

50

60

70

80

90

100

H a i r i n e s s Z w e i g l e 1 + 2

m m [ 1 / m ]

Com4am 108UT

Com4am 97UT

Conventionalam 108UT

Com4am 108Zweigle

Com4am 97Zweigle

Conventionalam 108Zweigle

Yarn Hairiness


2.5

2.65

2.8

2.95

3.1

3.25

3.4

3.55

3.7

3.85

4

6 7 8 9 10 11


0

10

20

30

40

50

60

70

80

90

100

H a i r i n e s s Z w e i g l e 1 + 2 m m

Com4am 108

UT

Com4am 97

UT

Conventionalam 108

UT

Com4am 108

Zweigle

Com4am 97

Zweigle

Conventionalam 108

Zweigle

Yarn Hairiness


U T

i n e s s

H a i r

H. Schwippl 17.11.06 36/56



Technology Handbook

By observing the long hairs of more than 3 mm according to Zweigle, one ascertains a very low absolute figure.Based on the low absolute figures, a statement seems inappropriate even when a clear trend to the advantage of

the COM4® system is obvious.

0

1

2

3

4

5

6 7 8 9 10 11

Garnfeinheit tex [g/1000m]

Z w e i g l e H a i r i n e

s s s 3 [ 1 / m ]

Com4

am 108Roving 400 tex

Com4

am 97Roving 400 tex

Conventional


Com4


Com4

am 97Roving 530 tex

Conventional


Yarn Hairiness

Reliance Polyester 0.9 dtex 40 mm

Ideally, no dependence of the COM4® yarn to the yarn number resp. no increase in hairiness with increasing yarnnumbers is shown. This means that the raw material in the yarn number area tested can be well compacted.

With the yarn winding and in the subsequent winding process, a lower hairiness also has a positive effect on thenep values through lower fibre suspension.

The yarn abrasion of ring yarns continues to be an indirect measurement for the yarn hairiness. Between the yarnhairiness and the pilling behaviour, experience has shown that generally a good correlation exists. High hairinessvalues lead to a higher unwanted pilling behaviour. Using the Staff tester, a measuring speed of 50 m/min over atime span of 10 minutes was recorded. By observation of the yarn abrasion per yarn weight unit, the abrasion

amount with yarns that become coarser must inevitably reduce logarithmically as the abrasion relates to the yarnweight and a smaller reference length results. As the influence of the yarn length on the abrasion is higher by farthan the influence on the yarn diameter, the reference length “abrasion in mg per 1000 m yarn” was selectedfor this reason.

Under the criteria of the yarn reference length, the abrasion values between the positions as well as with the S 3hairiness show too low absolute numerical values, so that under this quality criteria no explicit differencesbetween the spinning systems of the yarn twist and the roving characteristic are visible.

H. Schwippl 17.11.06 37/56



Technology Handbook

4.3.9. Yarn resistance against mechanical influence

Along with the mentioned yarn criteria, the yarn resistance in the down stream process and the usagecharacteristics in the textile fabric is an important criteria. For this purpose, the delaying tendency with a particularcycles of webtester cycles was examined using the Reutlinger Webtester. With the assistance of this measuringmethod, the resistance of the most important stress on the warp threads in weaving can be simulated. At thispoint, the measuring values should be applied as criteria for the precision of the fibre bonding in the yarn. Here,the presumption is that a resistant yarn not only shows advantages in the weaving process but in all furtherprocessing stages up to the textile fabric.

When comparing yarns with the same yarn twist factor of mα 108 it is evident that the COM4® yarn displays a

much higher number of abrasion revolutions before a thread break occurs. The sagging of the yarn overstressed

from cycles was already counted as yarn break.

This means the final spinning system can have a greater influence on the abrasion resistance than the yarn twist.This finding is remarkable and shows what potential can also exist with Polyester micro fibre in the yarn structurewith constant yarn twist.

0

400

800

1200

1600

20002400

2800

3200

3600

4000

0 1 2 3 4 5 6 7 8 9 10

Ends down results

C y c l e s o f W e b t e s

t e r T o u r s

Com4am 108

Com4am 97

Conventionalam 108

Yarn resistance with a Yarn Count of 10 tex


H. Schwippl 17.11.06 38/56



Technology Handbook

In addition, the surface roughness was also visually observed after the respective maximum number of cycles.The pictures clearly show with the example of a 10 tex yarn, the advantages of a yarn structure where the outer

fibres are better bound into the yarn body. Next to the very great influence of the yarn twist, a good binding of theouter fibres in the yarn body exerts a clear advantage on the yarn resistance. That means the combination of ayarn twist of mα 108 with a good binding of outer fibres leads to an excellent yarn resistance with the Reliance

micro fibres. A lower resistance tendency is advantageous for the subsequent winding process up to the followingdownstream process in the values of the textile fabrics. Conditional upon the greater fibre surface with microfibres, pilling has always been a big theme especially in the past. The improved fibre binding with the COM4® system will also here have a positive effect.

Com4, mα 108 Com4, mα 97 Conventional, mα 108

after 3550 cycles after 775 cycles after 1500 cycles

H. Schwippl 17.11.06 39/56



Technology Handbook

4.3.10. Conclusion

The yarn usage of synthetic staple fibre has increased enormously. The Polyester staple fibre production aloneamounts today to approx. 13 million tons per year. Within the Polyester staple fibre, the micro fibre has also wonin importance over the years.

When considering the fibre stress over the individual process stages, it is clear that the highest attention must bepaid to the Card and therefore offers the greatest challenge to increase performance in the spinning process withminimal fibre stress and good carding quality.

With increasing card production, a somewhat lower roving force and a higher variation of the roving force throughthe carding process can be ascertained.

Experience has shown that Polyester represents the greatest challenge with regard to a controlled fibre feed in

the compact technology on the final spinning machine. Clear advantages with the application of the final spinningtechnology COM4® could, however, be demonstrated.

The COM4® final spinning system shows also with the PES micro fibres used distinct advantages in the yarn thinand thick places thanks to the better fibre binding. The preliminary process from the Card to the rovingsignificantly influences the compacting results. Despite the relatively high yarn strength resulting from therelatively high number of fibres in the cross-section, the average strength, however, could be noticeablyincreased. The physically positive yarn measurements become very clearly apparent in the yarn resistance.

H. Schwippl 17.11.06 40/56



Technology Handbook

4.4. Processing characteristics of Tencel ® LF microfibres on high-performance machinery

4.4.1. Properties of cellulose fibres

Viscose

• Wet strength 12 – 14 [cN/tex]

• very good moisture absorption (higher than cotton)

• antistatic

• can be dyed in brilliant colours

• soft handle

• skin friendly

• easy – care

Modal

• same as viscose

• wet strength of 17 - 20[cN/tex]

Tencel ®

• same as viscose

• environmentally friendly manufacturing process

• better dimensional stability

• lower washing shrinkage

• wet strength of 31 – 37 [cN/tex]

4.4.1.1. Advantages of micro fibres

Spin-ability

• Spinning finer or stronger yarn Application

• sport sector for waterproof, airproof and breathable clothing

• low weight fabric with same functionality

• outerwearCharacteristics in textile fabric:

• silky appearance• silky drape

• pleasantly soft to touch

• better fabric lustre

• better humidity transport

Moisture transport in textiles is more efficient with increasing fibre surface. This effect can be amplified by approx.50% with the same yarn count, by using micro fibres of 0.9 dtex, compared with classical fibre counts of 1.3 - 1.5dtex.While the proportion of micro staple fibres in 1991 was merely 3’000 – 4’000 tons per year, today the total microstaple fibre production over all raw materials, amounts to approx. 600’000 tons annually.

H. Schwippl 17.11.06 41/56



Technology Handbook

4.4.2. New machine technologies

Carding System C 60

The new card-technology C 60, has totally changed the production limits. The entire geometrical conditions,especially the working width has changed from 1 m to 1.5 m, this results in much lower carding forces. Thecarding force between cylinder and flats has a large influence on overall productivity and quality.

The benefits become dramatically evident when working with man made fibres, especially with very fine fibressuch as micro fibres.

90 kg/hConventional card

90 kg/h

C 60 card

90 kg/hConventional card

90 kg/h

C 60 card

Fibre density on cylinder

Here we depict the fibre density onthe cylinder with the new cardingsystem C 60 in comparison with theconventional carding technology.

When the fibre density is too high, the carding force will increase. Excessive carding forces result in lower cardingquality. With the C 60 card, the fibres are spread out over a working width of 1.5 m. This results in a lower fibredensity, which enables a better carding quality and/or much higher productivity with the same quality.

H. Schwippl 17.11.06 42/56



Technology Handbook

Ring spinning frame K 44

The ComforSpin® system features non-wearing technology components such as;

• perforated drum,

• suction inserts and• air guide elements.

Technology components COM4 ®

Perforated drums plain fluted

Suction inserts primo linea

Air guide elements 46/0.5/2 52/0.5/2

COM4 ® twin

46/1.0/1

Perforated drums plain fluted

Suction inserts primo linea

Air guide elements 46/0.5/2 52/0.5/2

COM4 ® twin

46/1.0/1

Depending on the raw material and the number of fibres in the cross section, i.e. the yarn count, the technologycomponents and settings differ to achieve the best possible compacting results.

H. Schwippl 17.11.06 43/56



Technology Handbook

The R 40 Rotor spinning machine enables manufacturing of very fine yarns out of Tencel® LF, at the highestproductivity.

R 4R 4

0 Rotor spinning machine The SC-R spinning box0 Rotor spinning machine The SC-R spinning box

Standard opening unit

• Cotton

Opening unit for

• Synthetics• Blends (man-made rich)

• Cellulosics

Standard opening unit

• Cotton

Opening unit for

• Synthetics• Blends (man-made rich)

• Cellulosics

SPEEDpass

Standard channel insert

Channel insert with SPEEDpass

for additional airflowSPEEDpass

SPEEDpass

Standard channel insert

Channel insert with SPEEDpass

for additional airflowSPEEDpass

SPEEDpass channel

additional air flow for

constant fiber transport

SPEEDpass channel

additional air flow for

constant fiber transport

H. Schwippl 17.11.06 44/56



Technology Handbook

4.4.3. Processing study

0.9 dtex

34 mm

LF

Lenzing100%

Tencel ® microfiber

0.9 dtex

34 mm

LF

Lenzing100%

Tencel ® microfiber

Raw material:

Reasons for selecting this fibre type:

• Performance limits of the new C 60 card technology combined with the new fibre technology.

• Compact-ability using the new COM4® spinning technology combined with the new fibre technology.

• Yarn finness at high productivity using the new R 40 Rotor spinning technology combined with the newfibre technology.

4.4.3.1. Results in raw material

0

2

4

6

8

10

12

14

16

18

20

22

Bale 1 Opening

B 3/4

Card

Chute

Card

C 60

Pre draw

frame

D 10

Finisher

D 35

Roving frame

F33

450 tex

Roving frame

F 33

530 tex

S h o r t f i b e r c o n t e n t < 1 2 . 5 m m [ % ]

Short fiber Card 30 kg/h




Fiber length AFIS (n) over process steps + card production C 60

Tencel® LF 0.9 dtex, 34 mm, 1 opening place, ring application

At the beginning of the spinning process, the question of the number of opening positions arises. With only oneopening position in the fibre preparation, no increase in short fibre content is apparent, up to a carding productionof 53 kg/h with the C60.

With a production rate of 63 kg/h, the fibre stress and thus the short fibre content slightly increase, by 1 – 2 % inabsolute numbers.

H. Schwippl 17.11.06 45/56



Technology Handbook

0

2

4

6

8

10

12

14

16

18

2022

Bale 1 Opening

B 3/4

Card

Chute

Card

conv.

Pre draw

frame

D 10

Finisher

D 35

Roving frame

F 33

450 tex

Roving frame

F 33

530 tex

S h o r t f i b e r c o n t e n t < 1 2 . 5 m m [ % ]


TD 400


TD 400


TD 450


TD 450

Fiber length AFIS (n) over process steps + conv. card production


Based of short fibre content, higher fibre stress is apparent in the conventional carding system, when comparedto the new C 60 card. A slight decline in short fibre content with the conventional card can be observed, in spite an increase in cardproduction. This apparent contradiction can be explained by under-carding.

The system is already at its optimum quality level here. An increase in card production has adverse effects oncarding results, due to an already excessive mass of fibres on the cylinder. This reduces fibre stress again andresulting in a lower short fibre content of barely 1%. There is thus an interaction between carding intensity andfibre stress.

At a similar card production of 35 kg/h – 38 kg/h, there is a 3% reduction in short fibre content in absolute termswith the C 60 card, compared to the conventional card.

05

1015

2025303540455055606570

Bale 1 Opening

B 3/4

Card

Chute

Card

C 60

Pre draw

frame

D 10

Finisher

D 35

Roving frame

F 33

450 tex

Roving frame

F 33

530 tex

F i b

e r s t r e n g t h [ c N / t e x ]

0246

810121416182022242628

F i b e r e l o n g a t i o n [ % ]

StrengthCard 30 kg/h




ElongationCard 30 kg/h




Fiber strength elongation over process step + card production C 60


The fibres lose approx. 1 - 2 cN/tex and 1% elongation due to fibre stress during the entire spinning process. Thegreatest fibre stress usually occurs in the carding process.

H. Schwippl 17.11.06 46/56



Technology Handbook

05

101520253035404550556065

70

Bale 1 Opening

B 3/4

Card

Chute

Card

conv.

Pre draw

frame

D 10

Finisher

D 35

Roving frame

F 33

450 tex

Roving frame

F 33

530 tex

F i b e r s t r e n g t h [ c N / t e x ]

02468101214161820222426

28

F i b e r e l o n g a t i o n [ % ]

StrengthCard 20 kg/hTD 400




ElongationCard 20 kg/hTD 400




Fiber strength elongation over process step + conv. card production


Despite the far higher carding performance with the C 60, strength and elongation turn out the same as on theconventional card, which is an indication of gentle carding with the C 60 system.

0

10

20

30

40

50

60

70

80

90

100

Bale 1 Opening

B 3/4

Card

Chute

Card

C 60

Pre draw

frame

D 10

Finisher

D 35

Roving frame

F 33

450 tex

Roving frame

F 33

530 tex

N e p s [ 1 / g ]

0

100

200

300

400

500

600

700

800

900

1000

N e p s s i z e [ µ m ]

Neps [1/g]Card 30 kg/h




Neps size [µm]Card 30 kg/h




Neps AFIS over process steps + card production C 60


The nep count on the card was reduced by approx. 80% with only one opening position. When a second openingposition was added in the spinning process, the nep count before the card infeed, was increased by approx. 20%.

Additional opening positions always entail the risk of additional nep formation, when processing man made fibres,which may have an adverse effect on results in regard to cleaning in the subsequent carding process.

On the other hand, of course, the fibre material must be adequately opened to ensure good carding and good nepremoval. The nep count characteristics in fibre preparation indicate, that one single opening position is adequate,where bale opening is good, as being achieved with the UNIfloc A 11 bale opening system.

H. Schwippl 17.11.06 47/56



Technology Handbook

4.4.3.2. Results ring yarn

The number of opening positions depends on various factors, such as• bale opening system

• type of raw material and its respective fibre cohesion

• fibre count

• residual moisture in the bale

• bale weight and compression

8

9

10

11

12

13

1415

16

17

18

5 8 11 14 17 20 23 26 29 32 35

Yarn count [tex]

I r r e g u l a r i t y C V m

[ % ]

1 Opening30 kg/hCVm%




Yarn irregularity over amount of opening places

Tencel® LF 0.9 dtex, 34 mm, card C 60, COM4

®, ring 40 mm, αm 110

The number of opening positions, exhibits no differences in terms of capacitive or optical yarn evenness test.

Y

25

26

27

28

29

30

31

32

33

34

35

5 8 11 14 17 20 23 26 29 32 35

Yarn count [tex]

S t r e n g t h T e n s o j e t [ c N / t e x ]

1 Opening30 kg/h

1 Opening63 kg/h

2 Opening30 kg/h

2 Opening63 kg/h

arn strength over amount of opening places

Tencel® LF 0.9 dtex, 34 mm, card C 60, COM4

®, ring 40 mm, αm 110

At a very high card production of 63 kg/h and in a yarn count range of 7 tex to 30 tex, a second opening positionhas a positive effect on average yarn strength and elongation. Strength can thus be increased by approx. 0.7cN/tex in absolute terms and by 0.2% in elongation.

H. Schwippl 17.11.06 48/56



Technology Handbook

8

9

10

11

12

13

14

15

16

17

18

15 20 25 30 35 40 45 50 55 60 65 70

Card production [kg/h]

I r r e g u l a r i t y C V m [ % ]

conv. card7 tex

conv. card10 tex

conv. card15 tex

conv. card30 tex

C 607 tex

C 6010 tex

C 6015 tex

C 6030 tex

arn irregularity ring yarn conventional over card production

Tencel® LF 0.9 dtex, 34 mm, 1 opening place, ring 40 mm, αm 110

The limits in card performance are most evident when working with man made fibres, especially with micro fibresand high carding forces between the flats and the cylinder. A decrease in yarn quality, such as IPI and yarnevenness results from this. A drop in cylinder speed and more difficult fibre transfer from the cylinder to the doffer,can be a related symptom.

In order to achieve carding productions of just 35 kg/h with the conventional card system, various settings andtechnology components had to be selected, to cope with the high carding forces.The conventional carding system had reached its limits at 35 kg/h card production, despite

• higher cylinder rotational speed

• a 5° reduction in the front angle

•lower point density on the cylinder wire.

20

21.5

23

24.5

26

27.5

29

30.5

32

33.5

35

15 20 25 30 35 40 45 50 55 60 65 70

Card production [kg/h]


conv. card7 tex

conv. card10 tex

conv. card15 tex

conv. card30 tex

C 607 tex

C 6010 tex

C 6015 tex

C 6030 tex

Yarn strength ring yarn conventional over card production

Tencel® LF 0.9 dtex, 34 mm, 1 opening place, ring 40 mm, αm 110

The carding performance with the C 60 system was increased up to 63 kg/h. In regard to yarn strength, with thesame amount of fibres, a massive reduction in carding forces can ultimately only be achieved by reducing thefibre density, to avoid any negative drawbacks in carding quality.The C 60 system distributes the fibres over a larger carding surface due to the wider card design, which results in

a massive reduction in fibre density and thus in carding forces.

H. Schwippl 17.11.06 49/56



Technology Handbook

20

21.5

23

24.5

26

27.5

29

30.5

32

33.5

35

5 8 11 14 17 20 23 26 29 32 35

Yarn count [tex]


G 3330 kg/h

G 3338 kg/h

G3353 kg/h

G3363 kg/h

K 4430 kg/h

K 4438 kg/h

K 4453 kg/h

K 4463 kg/h

Yarn strength, conventional and COM4 ®

Tencel® LF 0.9 dtex, 34 mm, 1 opening place, card C 60, ring 40 mm, αm 110

The final spinning system has a very high influence on yarn strength and elongation. An increase of up to 3.5 cN/tex in yarn strength is achieved using the COM4® system compared with theconventional ring spinning system at a yarn count of 7 tex.

2

2.4

2.8

3.2

3.6

4

4.4

4.8

5.2

5.66

5 8 11 14 17 20 23 26 29 32 35

Yarn count [tex]

H a i r i n e s s U T

G 3330 kg/h

G 3338 kg/h

G 3353 kg/h

G 3363 kg/h

K 4430 kg/h

K 4438 kg/h

K 4453 kg/h

K 4463 kg/h

Yarn hairiness Uster, conventional and COM4 ®


As a result of the significant increase in yarn strength with the COM4® system, it was to be expected, that thiswas due to the improved integration of the fibers into the yarn structure.

The hairiness of COM4® yarn is 1.6 points lower than conventional ring-spun yarn, when measured according tothe Uster method.

The difference in favour of COM4® yarn declines with heavier yarn counts and significant differences are nolonger visible above a yarn count of 30 tex. This is due to the greater resistance of the fibres against the

compacting air.

H. Schwippl 17.11.06 50/56



Technology Handbook

0

1

2

3

4

5

6

7

8

9

10

5 8 11 14 17 20 23 26 29 32 35

Yarn count [tex]

H a i r i n e s s Z w e i g l e 3 m m [ 1 / m ]

G 3330 kg/h

G 3338 kg/h

G 3353 kg/h

G 3363 kg/h

K 4430 kg/h

K 4438 kg/h

K 4453 kg/h

K 4463 kg/h

Yarn hairiness Zweigle, conventional and COM4 ®


The yarn hairiness measured with the Zweigle method is also much lower for the COM4® system, especially thedisturbing long fibres of > 3 mm. Also in this case, the differences decline as the yarn becomes coarser and no longer exists from a yarn count ofapproximately 30 tex.

4.4.3.3. Results in rotor yarn

12

12.5

13

13.5

14

14.5

15

15.5

16

10 12.5 15 17.5 20 22.5

Yarn count [tex]

Y a r n i r r e g u l a r i t y C V m % + C V 2 D %

CVm%Card 30 kg/h

CVm%Card 38 kg/h

CVm%Card 53 kg/h

CVm%Card 63 kg/h

CV 2 D %Card 30 kg/h




Yarn irregularity rotor yarn over yarn count

Tencel® LF 0.9 dtex, 34 mm, 1 opening place, card C 60, rotor 130000 rpm, αm 110

By increasing the card production from 30 – 63 kg/h, only small differences were apparent in yarn evenness aswell as thick and thin places.

H. Schwippl 17.11.06 51/56



Technology Handbook

0

300

600

900

1200

1500

1800

2100

2400

2700

3000

10 12.5 15 17.5 20 22.5

Yarn count [tex]

Y a r n p u r i t y - 3 0 % ,

+ 3 5 % ,

+ 1 4 0 %

[ p e r 1 0 0 0 m y a r n ]

ThinCard 30 kg/h

ThinCard 38 kg/h

ThinCard 53 kg/h

ThinCard 63 kg/h

ThickCard 30 kg/h

ThickCard 38 kg/h

ThickCard 53 kg/h

ThickCard 63 kg/h

NepsCard 30 kg/h

NepsCard 38 kg/h

NepsCard 53 kg/h

NepsCard 63 kg/h

Yarn purity rotor yarn over yarn count


With higher card production, only an increase in the nep count of 10% to 25% is apparent.

10

11.5

13

14.5

16

17.5

19

20.5

22

23.5

25

10 12.5 15 17.5 20 22.5

Yarn count [tex]


5

5.5

6

6.5

7

7.5

8

8.5

9

9.5

10


Strength

Card 30 kg/h

Strength

Card 38 kg/h

Strength

Card 53 kg/h

Strength

Card 63 kg/hElongationCard 30 kg/h




Yarn strength and elongation rotor yarn over yarn count


Despite the high rotor speed of 130’000 rpm and a twist factor of mα 110, the running properties on the rotor-

spinning machine were excellent, even at a yarn count of 10 tex.

The advantages of the new machine technology, such as SPEEDpass in combination with Tencel® LF microfibres, enables spinning of very fine yarns with only 110 fibres in the cross section and very high productivity.

H. Schwippl 17.11.06 52/56



Technology Handbook

4.4.3.4. Yarn structure

15 tex, 50-times magnified

Card conventional, 25 kg/h, Ring yarn conventional, mα 110

Card C 60, 30 kg/h, ring yarn conventional, mα 110

Card C 60, 30 kg/h, ring yarn COM4 ®, mα 110

Card C 60, 30 kg/h, Siro yarn conventional, mα 110

Card C 60, 30 kg/h, COM4 ® twin, mα 110

Card C 60, 30 kg/h, rotor yarn, mα 110

H. Schwippl 17.11.06 53/56



Technology Handbook

4.4.3.5. Downstream processing

0.300

0.340

0.380

0.420

0.460

0.500

0.540

0.580

0.620

0.660

0.700

5 8 11 14 17 20 23 26 29 32 35

Yarn count [tex]

Y a r n d e n s i t y [ g / c m 3 ]

Yarn density over yarn count + end spinning systemTencel

® LF 0.9 dtex, 34 mm, 1 opening place, card C 60

R 4030 kg/h

R 4038 kg/h

R 4053 kg/h

R 4063 kg/h

G 3330 kg/h

G 3338 kg/h

G3353 kg/h

G3363 kg/h

K 4430 kg/h

K 4438 kg/h

K 4453 kg/h

K 4463 kg/h

• Yarn density in g/cm3 is influenced considerably by the yarn twist and the spinning process, more sothen the fibre preparation.

• Yarn density can thus be calculated by means of optical diameter measurement on the UT 4.

• Yarn density in turn, influences fabric handle in the textile fabric as well as dyeing.

• Yarn diameter influences the covering capacity of the textile fabric.

•

Covering capacity, therefore, turned out best with rotor-spun yarn, where as fabric-hand was softer withthe compact yarn.

Reutlinger Webtester

The abrasion resistance is an important criterion in downstream stages of yarn processing and service-ability oftextile fabric properties.

For this purpose, the abrasion tendency after a certain number of cycles was tested with the ReutlingerWebtester.This measuring method enables the simulation of the yarn resistance of the warp ends in weaving veryaccurately.

At this point the measured values should be consulted as a criterion for the accuracy of fibre integration into theyarn body.

H. Schwippl 17.11.06 54/56



Technology Handbook

0

60

120

180

240

300

360

420

480

540

600

0 1 2 3 4 5 6 7 8 9 10

Quasi yarn break

C y c l e s o f W e b t e s t e r T o u r s

conv. cardRing conv

Card C 60Ring conv

Card C 60Ring COM4®

Card C 60Ring convSiro

Card C 60Ring COM4® twin

Card C 60Rotor

Abrasion resistance over end spinning system

Tencel® LF 0.9 dtex, 34 mm, 1 opening place, 15 tex

Card production

C 60 = 30 kg/h

conv. card = 25 kg/h

The chart shows the number of cycles up to the yarn break. The highest number of cycles was measured with theconventional siro yarn and COM4®twin.

C 51, 25 kg/h, 62 cycles

Ring conventional


Ring conventionalC 60, 63 kg/h, 112 cycles

Ring conventional


COM4®


Ring conventional


Ring conventionalC 60, 63 kg/h, 112 cycles

Ring conventional


COM4®

Fibre preparation obviously has also an influence on the degree of abrasion resistance.

In the conventional Ring-spun yarn, the conventional card operating at 25 kg/h, recorded a short fibre content(SFC) (n) of 8%, which is more then twice the short fibres of the C 60 at 30 kg/h.

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Siro conventional


COM4®twin


Rotor C 60, 30 kg/h, 311 cycles

Siro conventional


COM4®twin


Rotor

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The Ring-spun Siro yarns recorded the highest resistance in abrasion. No fibre abrasion was apparent here, evenafter 330 abrasion cycles and 9 quasi yarn breaks.

The structure of Rotor-spun yarn is also very resistant to fibre abrasion, but the set limit for this test of 9 threadbreaks, was already reached after 49 abrasions passes.However, a positive influence can be exerted by means of yarn twist. But this changes other yarn properties and

the productivity of the Rotor spinning machine accordingly.

4.4.3.6. Summary

The following findings can be recorded on the basis of processing Tencel® LF 0.9 dtex /34 mm micro fibres:

• The C 60 carding technology sets new standards for productivity and quality when processing new fibretechnologies such as micro fibres. Card production is 80% higher than conventional carding systems.

• Tencel® micro fibres result in significant compacting success up to yarn counts of 30 tex. With fine yarns, the

hairiness was substantially reduced further. Strength increased accordingly by up to 3.5 cN/tex.

• With this raw material, the COM4®twin technology enables massive improvements to be achieved inhairiness, strength and abrasion resistance.

• The R 40 Rotor spinning technology enabled yarn counts of 10 tex to be achieved with Tencel® micro fibres,at rotor speeds of 130’000 rpm.



Technology Handbook

2. Laboratory Tests

1. GENERAL GUIDELINES FOR SPINNING TESTS 6

1.1. Fibre material required for standard tests 6

2. LABORATORY INSTRUMENT 7

2.1. Evenness testing Uster UT4 capacitive versus optical-measuring method 72.1.1. Yarn overview / Test conditions 72.1.2. Case „yarn system“ 100% Polyester 1,5 /38mm, yarn Ne 50 82.1.3. Case „back-winding“ 100% cotton 1 1/8“ combed, yarn Ne 30 10

2.1.4. Case „test parameter - reaction“ 100% cotton combed, yarns Ne 50 / Ne 30 122.1.5. Case „raw material staple“ 100% Polyester staple, yarn Ne 28..50 142.1.6. Summary 172.2. Detention-length measurement with “Cohesion-Meter Rothschild” 182.2.1. Situation 182.2.1.1. Task 192.2.1.2. Goal 192.2.2. Purpose of the testing method 192.2.2.1. Terms of measuring data from the Cohesion-Meter 202.2.2.2. Evaluation of the new drafting spectrum 212.2.2.3. Test conditions 242.2.2.4. Experience values 25

2.2.3. Test procedure / Feasibility 252.2.3.1. Raw material 272.2.3.2. Spinning plan 272.2.3.3. Position chart 272.2.4. Analysis / Examinations 282.2.4.1. Roving /Cohesive-length 282.3. Instruction to evaluate area-measured materials 302.3.1. Initial position 302.3.1.1. The path to evaluation method - 4/06 302.3.2. Criteria for the evaluation – 4/06 302.3.2.1. Sampling 302.3.2.2. Colour of the test specimen 312.3.2.3. Reference pattern 312.3.2.4. Group of patterns 312.3.2.5. Evaluation forms 312.3.2.6. Evaluation personnel 322.3.2.2. Criteria for fabric inspection table 332.3.2.3. Varieties of evaluation 332.3.3. Evaluation guideline - 4/06 342.3.3.1. Appearance of goods and imperfections 342.3.3.2. Covering factor 362.3.3.3. Fabric-hand 362.3.3.4. Surface-area of goods 37

2.3.3.5. Obvious fabric defects 382.3.3.6. Example of fabric evaluation - 4/06 38

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2.3.3.7. Comparison of evaluations 392.3.3.8. Forms 39

3. TEXTILE UNITS AND DEFINITIONS 40

3.1. Yarn count system 403.2. Classification of cotton 403.3. Yarn break standards 413.4. Spinning limits 413.5. Climatic guidelines 423.6. Quality values 42 3.7. Basic conversion charts 433.7.1. Textile conversion formulas 44

4. TEXTILE TESTING 48

4.1. Parameters for fibre testing / sorted by instruments 484.1.1. AFIS – Neps, Length & Trash 484.1.1.1. AFIS-N (Neps) 484.1.1.2. AFIS- L&M (Length and Maturity) 484.1.1.3. AFIS- L&D (Length and Diameter) 484.1.1.4. AFIS-T (Trash) 484.1.1.5. AFIS-S (Fibre length for man made fibres) 494.1.2. Almeter 101 - Capacitive fibre length measurement 494.1.3. Single Fibre Measurement – Manual Staple 494.1.4. FCT – Stickiness, Neps, Trash 49

4.1.5. FQT – Stickiness, Neps, Trash, Fineness 504.1.6. Fehling – Chemical determination of stickiness 504.1.7. Graf SCT- Stickiness Thermodetector 504.1.8. H2SD – High Speed Stickiness Detector - Stickiness 504.1.9. HVI – High Volume Instrument – Tenacity, Fineness, Color 504.1.9.1. HVI -910 (ICC-cal) Fibre length measurement, Bundle strength 504.1.9.2. HVI -910 (HVI-cal) Fibre length measurement, Bundle strength 514.1.9.3. HVI -920 Micronaire 514.1.9.4. HVI -930/35 Color and Trash 514.1.9.5. HVI - Spectrum (only HVI - Calibration) 524.1.10. MDTA3 / ITV – Trash content 524.1.11. NATI 524.1.12. Parallex - Parallelism in Sliver 534.1.13. Pressley – Bundle Strength 534.1.14. Rothschild – Adhesive length (Tenacity) 534.1.15. Shirley / Selecter – Trash content of raw cotton 534.1.16. Shirley FMT – Maturity via Airflow 534.1.17. Stelometer – Fibre Bundle Strength 534.1.18. UT3 / UT4 – Capacitive Sliver and Roving Unevenness 534.1.19. Vibrojet – Single fibre fineness and tenacity 544.1.20. Vibrotex – Single fibre crimp 544.1.21. Vibroskop / gravimetrical fineness determination 544.1.22. Zweigle – Twist in Roving 54

4.1.23. Zwick – Tenacity in Fabrics 554.1.24. Zwick – Adhesion Length (Tenacity) 55

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4.2. Parameters for yarn testing / sorted by instruments 554.2.1. Autosorter – Yarn fineness 55

4.2.2. OPTRA- optical trash content in yarn 554.2.3. Reutlinger Webtester - Simulation of yarn abrasion at the weaving loom 554.2.4. Uster Classimat – Yarn faults 564.2.5. Uster Tensojet - Tenacity 564.2.6. Uster Tensorapid / Tensokid- Tenacity 574.2.7. CBL Variation of length 574.2.8. Uster Tester – Evenness Tester 574.2.8.1. Uster Tester 3/4 - CS 574.2.8.2. Uster Tester 3/4 - OH 574.2.8.3. Uster Tester 3/4 - FA-Module 574.2.8.4. Uster Tester 4 - OM 584.2.8.5. Uster Tester 4 - OI 58

4.2.9. Zweigle D301 – Twist measurement 584.2.10. Zweigle G565/G566 – Optical hairiness 584.2.11. Zweigle G580 - Optische Unevenness 584.2.12. Zweigle G555 - Stafftester - Abrasion 59

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1. GENERAL GUIDELINES FOR SPINNING TESTS

The Rieter Technology laboratory recommends and requires the following amounts of fibre material, to perform allnecessary quality control tests.

Blowroom and card 500 – 600 kg fibre material (min. 2 bales) Blowroom and C60 card 800 – 1000 kg fibre material (min. 4 bales) Combing 250 – 300 kg card sliver Drawing 250 – 300 kg carded or combed sliver Roving frame 75 – 125 kg Drawframe sliver Ring spinning /COM4 35 – 50 kg roving (min. 24 roving bobbins) OE – Rotor 75 – 100 kg Drawframe sliver of Nm 50 and finer

150 – 200 kg Drawframe sliver of Nm 20 and finer250 – 400 kg Drawframe sliver of Nm 20 and coarser

1.1. Fibre material required for standard tests

Standard test per position for fibre tufts / slivers / roving:

Type of test Device Fibre tuft Sliver Roving Numberof tests

Min.amount gr.

Staple length Almeter 1 0.5 0.5 3 80

Strength /Fineness Spectru – HVI 0.5 - - 10 80

Trash content ITV or 1.5 1 1 3 120

Selecter 2 1.5 1.5 2 300

Neps AFIS 0.5 0.5 0.5 5 10

Total amount needed for standard laboratory work 500 g

Standard test per position for yarn:

Type of test DeviceNumber of cops /

bobbins

Min.amount per cops /

bobbin in mFineness Autosorter 3 3 80

Strength UTR 10 80

Evenness UT3 / UT4 3 120

Hairiness ÚT3 / UT4 2 300

Total amount needed for standard laboratory work 1425 m

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2. LABORATORY INSTRUMENT

2.1. Evenness testing Uster UT4 capacitive versus optical-measuring method

State of the art The yarn evenness is still measured to the largest extent with the Uster tester on the "capacitive" basis. Theexpressed CVm% value is well known around the whole world.With the introduction of the Uster tester 4 (UT4), the possibility exists to capture the yarn evenness also through the"opto-electronic" measurement principle. The yarn diameter is determined two-dimensional with a reference length of0.3 mm and the received value is expressed as CV 2D-0.3.

It is not the purpose to embrace the measuring systems here, but the measured data and their dependence.

If we compare the two evenness values of the capacitive and optical method, we can determine discrepancies rankedfrom none to very large.

The optical value can practically correspond to the one of the capacitive. There are measurements were cleardeviations are registered, i.e. the optical value can be better or worse in relation to the capacitive result. This pointsout, that the optical method assesses in addition to the IPI variables, further dependencies.

These dependences are listed thereafter based on test results.

2.1.1. Yarn overview / Test conditions

The compositions are based on data from four projects. The conditioned yarns were examined in our textilelaboratory.

This projects consist of:- Yarn Ne 50, 100% Polyester „Grisuten“ 1,5 dtex / 38 mm- Yarn Ne 30, 100% cotton 1 1/8“ combed- Yarn Ne 50 / 30, 100% cotton combed- Yarn Ne 28..50 100% PES „Tergal“ with two different staple lengths

One compares always between the capacitive and the optical-electronic measuring system within a project, startingwith the UT4 tester.

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2.1.2. Case „yarn system“ 100% Polyester 1.5 /38mm, yarn Ne 50

It concerns three types of ring yarn, produced with different spinning systems.The optical CV 2D-0.3 shows lower values with all three types of yarn, therefore better values compared to thecapacitive CVm:

- with yarn A -0.5 %- with yarn B -1.1 %- with yarn C -1.8 %

Why is the CV 2D-0,3 better than the CVm and will the span continue to increase?

The variations of the yarn types B and C to the reference type A are specified in the following graph. The test parameters are, the Uster CVm%, CV2D-0.3 and the hairiness.

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The variations of the yarn types B and C to the reference type A are specified in the following graph. The test parameters are, the Uster CVm%, CV2D-0.3 and the thin and thick places.

With yarn B the capacitive CVm value is unchanged compared to yarn A. The optical CV 2D-0.3 value showshowever a descending tendency, although the thin and thick places are increasing. The hairiness - analysed with UT4and Zweigle - exhibits an equivalent decrease. Here the optical CV 2D-0.3 reacts stronger to the hairiness than to thethin and thick places. With the capacitive CVm the reverse holds true, the thin /thick places affects the mass deviationquadratic, substantially more than the hairiness difference.

With yarn C the CVm value drops moderately, however the CV 2D-0.3 value clearly improves compared to the yarn B.The thin and thick places experience a noticeable improvement and therefore affect the CVm value positively.The optical CV 2D-0.3 achieves a solid decrease compared to the capacitive CVm. This is due to the clear reductionof the visual hairiness, measured with the Zweigle method. As contrast, the hairiness of the optically captured UT4-Hvalue, experiences a noticeably smaller reduction.

The capacitive evenness CVm, starting with the UT4, is clearly affected by the thin and thick places. But also to bementioned, that even the hairiness variability interferes easily with the capacitive evenness, which until now, alwaysrepresented an uncertainty. The optical-electronic evenness CV 2D-0.3, starting with the UT4, is affected primary by the visual hairiness(based on Zweigle) and secondary by the thin and thick places. The CV 2D-0.3 values exhibit a very close similarityto the Zweigle S3 data.

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All test characteristics are represented again in the following graph, with the yarns B and C in relation to the yarn A.The yarn C exhibits a very effective compacting, measured by Zweigle.

2.1.3. Case „back-winding“ 100% cotton 1 1/8“ combed, yarn Ne 30

Two equal ring yarns are concerned here, however in cops and back-wound condition.Unlike in the preceding example, the optical measurement indicates higher CV 2D-0.3 values, thus worse values inrelation to the capacitive measuring system CVm:- with yarn from cops + 0,9 %- with yarn from package + 1,9 %

Why is here the CV 2D-0.3 worse than the CVm and is the span widening?

In this case, the optical-electronic evenness lies clearly above the capacitive evenness, because the hairiness - andin particular the visual part - of these yarns is elevated.As comparison between yarns from cops versa yarns from package the capacitive CVm value remains almost thesame. The optical CV 2D-0.3 value behaves very different, as it significantly increases with the yarn from package,versus yarn from cops.

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What is the reason for the difference? The thin and thick places behave like the CVm value between the yarns fromcops respectively package and remain almost unchanged. However, the hairiness increases modestly whenexamined by Uster and very strongly when tested with Zweigle, between the yarns from cops vs. the yarns frompackage. The capacitive evenness is not substantially affected despite the moderate respectively strong increase ofthe hairiness. In opposite, the optical-electronic measurement reacts very sensitive to the increase in visual hairiness – and as already determined - with the yarn from package, the CV 2D-0.3 value is clearly worse.



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The variations between the yarn from cops (Ref.) and from package (back-wound yarn onto a cross-wound package)are shown in the following graph. The test parameters are, the Uster CVm%, CV2D-0.3 and the hairiness.

The variations between the yarn from cops (Ref.) and from package (back-wound yarn onto a cross-wound package)are shown in the following graph. The test parameters are, the Uster CVm%, CV2D-0.3 and the thin and thick places:

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Judging by the capacitive measuring system, the yarn hairiness between the cops and package, might not changesubstantially.

However as generally known, an unwanted significant increase in the hairiness results during the rewinding process.This visual change in the S3 value, of the 2.2..3-fold, is particularly recognizable with the Zweigle measuring method.The hairiness increase after rewinding according to the capacitive principle, amounts to "only" the 1.2..1.35-fold.

This significant increase of the visual yarn hairiness is only captured with the optical-electronic measurement atthe UT4.

2.1.4. Case „test parameter - reaction“ 100% cotton combed, yarns Ne 50 / Ne 30

In this case, it concerns back-wound ring yarns of two yarn counts from similar raw material. Here it predominantly

concerns the reaction of the test parameters and not about the data numbers.In this example, the optical measuring method (CV 2D-0.3) shows a lower and a higher value, as compared to therespective capacitive CVm values:- with yarn Ne 50 from package - 1.3 %- with yarn Ne 30 from package + 1.9 %

Why is in this case the CV 2D-0.3 better and worse than the CVm at a large span?

The variations of the test parameters with yarns Ne 50+30 are specified in the following graph.The test parameters are, the Uster CVm%, CV2D-0.3 and the hairiness.

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The variations of the test parameters of the yarns Ne 50+30 are specified in the following graph.The test parameters are, the Uster CVm%, CV2D-0.3 and the thin and thick places.

Judged by the capacitive measuring method no considerable difference in the CVm values exist between the twoyarns. This is to be attributed to the similar amount of thin and thick places. In this case, the relatively large increasein hairiness with the UT4, affects the CVm value only insignificantly.

However the optical-electronic evenness (CV 2D-0.3) exhibits a serious increase in contrast to the capacitivemethod, which has unchanged values. The large increase of the CV 2D-0.3 value, originates from the significantdeterioration of the visual hairiness, expressed in the S3 value.

The crossing-over effect between the capacitive and optical-electronic evenness, is clearly contingent on the largechange in the visual hairiness, whereby only the optical evenness changes. With low yarn hairiness, the CV 2D-0.3value is clearly below the CVm value, but worsens very significant with increasing visual hairiness, so that it ends upto be higher then the CVm value.

Judging by the capacitive CVm value, the yarn hairiness should not have changed substantially. Since this is not thecase, we must assume, that the hairiness has only a minimum influence on the capacitive measurement. We oftenrecognise, that with a descending CVm value the hairiness index H slightly increases.

The visual hairiness S3 affects the optical evenness always at a constant rate and intensive. The capacitive CVmvalue shows however no substantial effect. The hairiness H from the UT4 is obviously less sensitive, it follows at the same rate as the visual hairiness,however with a substantially smaller factor. It affects the CVm value only slightly and varies in intensity. Again, it shows remarkably how the optical evenness follows the results from the Zweigle S3.

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2.1.5. Case „raw material staple“ 100% Polyester staple, yarn Ne 28..50

This case demonstrates ring yarns in three counts, of polyester with staple length 38 mm (blue) and staple length <38 mm "variable" (green).

Depending on the staple length, the optical-electronic evenness is better or worse in comparison to the capacitiveevenness.Values in comparison to the CVm:- Staple length 38 mm - 0,4..0,7 %- Staple length < 38 mm + 0,7..1,2 %

Why is in this case the CV 2D-0.3 better and worse than the CVm?

The development over the yarn count is identical between the two measuring methods and the two staple lengths.

With Polyester yarns of rectangular staple (A: 38 mm = blue) the optical curve is positioned below the capacitiveone. The values of the optical measurement are better compared to those from the capacitive.

The Polyester yarns with triangular staple (B: < 38 mm = green) behave exactly in reverse. The values of the opticalmeasurement are worse compared to the capacitive. They are even slightly above the optical curve of the rectangularstaple. In addition, the deterioration of the optical measuring data of the finer yarns is larger, compared to theimprovement with the rectangular staple.

The variations of the test parameters with the two staple lengths are specified in the following graph.The test parameters are, the Uster CVm% and CV2D-0.3.

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To conclude from the previous realizations, the hairiness of the yarns from the triangular staple (< 38mm = green) hadto be expected to increase significantly.

The examinations with the UT4-H and Zweigle S3 actually result in higher hairiness values. The amount of theincrease in hairiness should however not be sufficient for the serious deterioration of the optical values. Apparently,additional not mass relevant variations must have been captured in the optical measurement.

In dependence of the yarn count, the development of the evenness vs. hairiness is opposite; i.e. with smaller mass,the evenness gets worse and the hairiness decreases.

With the capacitive examination the capacitive CVm values of the triangular staple yarns (< 38mm = green) areclearly better than the values of the yarns with the rectangular staple (38mm = blue).This is to be attributed to the changed number of thin and thick places in dependence of the staple length, i.e. themass-measuring method reacted very accurate to the reduction in defects.

The test parameters are, the Uster CVm% and thin- / thick places.

With the optical-electronic examination this large advantage of the yarn is completely lost with the triangular staple.The CV 2D-0.3 values from the triangular staple are even minimal worse, thus slightly over the CVm values incomparison to the yarn with rectangular staple.The optical CV 2D-0.3 values of the two staple lengths develop almost identical in dependence of the yarn count.In contrast, the values of the capacitive measurement deviate within the staple length very significant to each other.

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Why does the optical evenness suffer this loss with the triangular staple?Fact is that:

- the capacitive-measured thin and thick places of the triangular staple are better- the hairiness increase according UT4-H, moves only in the middle range- the visual hairiness increase according Zweigle S3, is also only moderate

However these facts might not be entirely sufficient, for the serious deterioration of the optical values.Apparently additional none-mass relevant faults must have been captured in the optical measurement.A hypothesis is, that the number of capacitive measured thick places is better, but perhaps more voluminous andhence reflected negatively with the optical-electronic examination.

In the textile technology, not all questions can be explained at the first attempt. However with this example, we gain afirst reference and are more sensitise to this fascinating technology.

The test parameters are, the Uster CV2D-0.3 and thin- / thick places.

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2.1.6. Summary

• The capacitive evenness "CVm" is still an ideal indicator for the changes of the IPI values.

• Approx. responsible: Thin places to 50%, thick places to 35% and neps to 15%

• The variation in hairiness affects the capacitive evenness only slightly, thus not in the full degree.

• The optical-electronic evenness "CV 2D-0.3" is a meaningful indicator for the actual variation in hairiness,i.e. tracks the visual hairiness.

• Therefore the optical evenness trails the hairiness "S3" measured with Zweigle very accurately.

• The optical measuring method of the UT4, can probably also capture voluminous thick places, which are hardly

noticeably with the capacitive method, however visually appear in the final product.

Therefore the optical evenness should be considered more, so that with sufficient experience, even a declarationabout the variation in visual hairiness could be made.

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2.2. Detention-length measurement with “Cohesion-Meter Rothschild”

The Cohesion Meter type R-2020 measures dynamically the cohesive-length of slivers and roving. The measuringinstrument was developed by the mid 70’s (rotor development) by Ems and Rothschild.This equipment was therefore predominantly used at that time, for the rotor development and for the measurement ofthe sliver cohesion in the chemical fibre application. With the help of the established cohesive length, someconclusions on the fiber / fiber friction could be made by chemical fibres and hence the opening behaviour at theRotor spinner.

Meanwhile - and in particular at Rieter - all raw materials and predominantly roving are tested, in order to findconclusions for the drafting behaviour at the Ring spinning frame.

2.2.1. Situation

Testing of roving shall:establish the cohesive-length respectively the cohesive-load between the different raw materials, evaluatethe draft ability of the roving-mass and roving-twist amount and to develop experience values, therefore thesame draft selection must remain for all tests,

on the other hand, the progression of the cohesive-load will become evident, with the various draftselections at the Cohesion meter and as a result, the setting with the highest value is assigned as theoptimal draft for the Ring spinning break draft area.

Drafts up to 2,5-fold are tested. But exactly within the draft range 1,1 to 1,25-fold - where Ring spinning operates inthe real world - the research values are missing, i.e. lack of adjustment possibilities.

Cohesion measurements with Cohesion-Meter

Cotton - Roving

With so many missingmeasurement points, thecohesive-load diagramshould not be representedwith a direct line.

If the measuring points are

merely connected,assumptions are madewithin the relevant range forRing spinning, whosevalues are uncertain andabove all unknown.

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2.2.1.1. Task

For the technologist the "cohesive-slide phase" is of importance, thus the range before the maximum cohesive-load.The break draft at the Ring spinning machine must be selected from the upper cohesive-slide phase, i.e. before themaximum strength, in order to achieve the optimal yarn results.The drafts at and after the highest point are for Rosining no longer of importance. Within this range the roving isalready drafted, which leads to uncontrolled false drafts and accordingly, the variation is much too wide. The Ringspinning break drafts from this range, would lead to a degradation of the yarn IPI values and the count range.To eliminate the above-mentioned uncertainties, the possibility to setup the Cohesion meter with the break draft range1,14 and 1,19, which is relevant for Ring spinning, must be achieved.

2.2.1.2. Goal

Assessing the cohesive-strength of roving, in smaller draft increments, which are representative of the Ring spinningbreak drafts.

2.2.2. Purpose of the testing method

The Cohesion-Meter was developed for the sliver evaluation within the MMF application, to attain know howconcerning the fiber / fiber friction. This was a very important fibre parameter for Rotor spinning, which gave suitableinformation about the fibre opening.Meanwhile predominantly roving - consisting of all types of raw material - is tested in the Rieter textile laboratory. Alsohere, it concerns the cohesive length, which is dependent on the fiber / fiber friction in the lightly twisted fibre ribbon.

The draft-ability in the Ring spinning drafting system depends greatly on the cohesive-strength of the applied roving.The roving strength affects the drafting performance in the Ring spinning drafting system and functioning of rovingand spinning frames.

At the roving frame, the roving strength can be optimized only based on the measuring data from the Cohesion-Meter;hence the ideal roving twist must be evaluated. The roving strength between front and rear row on the roving frame,can vary at times very strongly. These variations can be minimized only, with appropriate adjustments based on thedata from the Cohesion-Meter.

Excessive deviation in the cohesive-length of the roving, negatively affects the running behaviour of the roving andRing spinning frames. The yarn quality is influenced only insignificant by the cohesive-length deviation of the roving.However, insufficient drafting action will have a negative affect. With the ideal cohesive-length in control, a large

portion of drafting problems can be eliminated during the spinning process.

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2.2.2.1. Terms of measuring data from the Cohesion-Meter

Cohesive-strengthThe cohesive-strength in cN is the absolute strength of the roving, independent of the roving size. Therefore thecohesive-strength increases with increasing roving mass. Hence, no constant and ideal recommendation value canbe specified.

Cohesive-lengthThe cohesive-length in m is a relative strength of the roving, because it stands in relation to the roving mass.The cohesive-length in m concludes from:

m = cohesive-strength cN * delivery m/min * testing time min / sample weight g

Since the cohesive-length represents a strength in relationship to mass, a value within the roving size can berecommended.The following graph shows the cohesive-strength development, in dependence of the roving size and an assumedconstant cohesive-length on 1850 m.

From this it is evident, that for the cohesive-strength, no constant ideal experience value can be assumed over theentire count range. This value has to be calculated for each roving count.

Rel. StrengthThe relative strength in cN/tex originates from a dynamic testing method, however it can be used as relativecomparison to the yarn strength.

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2.2.2.2. Evaluation of the new drafting spectrum

In the two graphs, the old data curve without the drafts relevant to Ring spinning and the new curve with thecompleted drafting spectrum are shown.

Drafting spectrum oldWith the old drafting spectrum (approx. to Dec. 04) the measuring points in the draft range 1.1 up to 1.25 are directlyconnected. The maximum strength for all raw materials is reached with a 1,25-fold draft. As a result, a 1,25 breakdraft would be selected for the Ring spinning frame. This could apply for chemical fibres however, not for carded orcombed cotton in the middle staple range.Since uncertainty exists concerning the development of the curve, it is necessary to measure the drafts, which lay inbetween these points.

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Draft spectrum new The new draft spectrum was extended with the drafts 1.15 / 1.19 and 1.35. The additional measuring points exhibit

now a substantially changed development of the curve.The maximum strength is reached between the drafts 1.15 and 1.25. The short staple, carded cotton lies at the draft1.15 and the long staple combed cotton at the draft 1,25.This allocation according to the quality of the raw material makes now sense.

In the following graph exhibits the new draft spectrum.

From these curves the recommendations for the ideal break drafts at the spinning machine can be derived:- Cotton 1 3/32" carded VV = 1.14- Cotton 1 1/8" combed VV = 1.19

- Cotton 1 7/16" combed VV = 1.19... 1.24- Blends: 65% Polyester 35 % Cotton comb. VV = 1.19... 1.24- 100% Polyester 1,5” / 38 mm VV = 1.19 (1,24)

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Recording of the cohesive-strengthThe development of the curves corresponds naturally to the cohesive-length. The heights of the curves are

significantly changing in the cohesive-length recording. The lowest cohesive-length curve, of the carded cottonroving, becomes now the highest curve. Because this roving exhibits the highest mass, therefore the highestcohesive-strength results.When the ideal values - converted from 1850 m cohesive-length – are compared to the actual values, it also becomesevident with the cohesive-strength, that the raw materials B / D and E are on target. The roving strength of the rawmaterial A could be slightly stronger and those of the raw material C would have to be considerable weaker.

With the roving strength too low, no drafting disturbances are to be expect however, an increase in roving breaks andsporadic sliding apart of the roving in the break draft zone can lead to long thin places.

With the roving strength too high, as shown with raw material C, draft disturbances occur and lead to increased IPIvalues. This case is often found in practical applications and especially with Compact-Spinning substantially more

sensitively.In the following graph shows the cohesive-strength in connection with the new drafting spectrum.

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2.2.2.3. Test conditions

Test extent/pos: 3 roving bobbins per each test.Deviation CV%: To collect representative experience values for comparisons, the CV value should be < 10%,otherwise the test must be doubted,carded cotton is slightly higher < 13%.

Drafts: To visualize the development of the strength-curve, the complete draft spectrum must be tested,but only drafts up to a decreasing strength are meaningful, because as soon as the rovingribbon slides apart the spread increases severely; i.e. maximum draft of 1,35-fold.

Bobbin-DM: Even the diameter of the roving bobbin can change the strength up to 10%, depending on theroving frame settings, the strength is general higher on the smaller diameter (beginning of coil).The tests should be done predominantly with the smaller diameter with a notation of thediameter.

Setup: the settings on the Cohesion meter are made according the existing instruction.

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2.2.2.4. Experience values

The experience values are based on a draft of 1.10-fold. This draft was selected initially, because this was thehighest possible draft with the smallest scattering.Since the cohesive-length represents a strength related to fineness, this data can be collected as experience values.Recommendations within the Roving fineness result from this data. From some long-term studies in practicalapplications, the ideal cohesive-length - with a draft of 1.10 - can be established within the following ranges:- Roving with 100% cotton 1750 ... 1900 m (for Com4 rather within the lower range)- Roving with 100% chemical fibres 1800 … 2000 m.

These values are guidelines, for a trouble-free draft the actual condition of the Ring spinning drafting system must beconsidered.

2.2.3. Test procedure / Feasibility

The following diagram shows the desired draft spectrum with the existing and the new suggested drafts.

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To adjust the desired draft spectrum on the Cohesion meter, - while maintaining the gear train - the feasibility with theexisting and possible new change gears was examined. The following table shows draft, which can be realized.

Drafts between 1.05... 1.35 are accomplished with the driver-gear 22 teeth (blue) and the draft 1.50 with the driver-gear 33 teeth (red). For the drafts 1.50 and 1.35 the gears from the gear combination "red", must be used.

Gearing diagram of the Cohesion Meter R2020 (~1980) with the new gear combination.

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2.2.3.1. Raw material

The draft spectrum was tested with the following raw materials.

Position A B C D E

Raw Material Cotton 1 3/32“carded

Cotton 1 1/8“combed

Cotton 1 7/16“combed

Polyester GrisutenCotton combed

Polyester Tergal1,3dtex / 38mm

Blend 100% 100% 100% 65% / 35% 100%

2.2.3.2. Spinning plan

The roving of the raw materials positions A .. D, were collected from customers.

Pos. Machine Type

Feed

[tex]

Doubling

[fold]

Draft

[fold]

Delivery

[tex]

Delivery

[ Ne ]

Twist

[ T/m ]

A Roving 1 1180 0.5

B Roving F33 1 695 0.85

C Roving Zinser 1 420 1.4

D Roving F33 1 770 0.77

E Roving F10 1 590 1.0

2.2.3.3. Position chart

Draft Material A Material B Material C Material D V E Gear Driver Gear

Change

1,05 A1 B1 C1 D1 E1 22 67

1,10 A2 B2 C2 D2 E2 22 64

1,15 A3 B3 C3 D3 E3 22 61

1,19 A4 B4 C4 D4 E4 22 59.0

1,25 A5 B5 C5 D5 E5 22 56.0

1,35 A6 B6 C6 D6 E6 22

1,50 A7 B7 C7 D7 E7

52

33 70

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2.2.4. Analysis / Examinations

The analysis was performed in the Rieter textile laboratory. Three roving bobbins of each raw material were tested.Bobbins of ¾ full and larger were examined.

2.2.4.1. Roving /Cohesive-length

The following table contains all strength data from the Cohesion meter.

The strength data are: Cohesive load in cNCohesive length in mCoefficient of variation in CV%

The data of the cohesion-strength is summarized in the graph Ideal Roving Cohesion Strength in relation to rovingfineness under point 2.2.2.1.

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2.3. Instruction to evaluate area-measured materials

2.3.1. Initial position

During the evaluation of a finished blend-fabric, polyester /cotton for Job-wear, it was recognized that the existingevaluation method of fabric samples was not especially suited with the existing tools. In addition, no written guidelinesor instructions were present.Therefore the existing method was developed further. The goal of this advancement was to simplify the evaluationand to document the process in an official directive (instruction).

2.3.1.1. The path to evaluation method - 4/06

The path to the new evaluation method arrived from experience, i.e. based on the above mentioned fabricevaluations. One can state that the fabric from conventional ring yarn is to be viewed as the most pleasant.This is not sufficient for the evaluation of the quality of fabrics. Because not only the fabric appearance is decisive, butalso the fabric-hand.The “fabric-hand“ is considered one of the most important quality parameters for apparel. The hand is based on thereaction to the sense of feeling, to estimate the quality of a fabric.The fabric-hand of textile goods was not considered in the existing (old) fabric evaluation. Also an evaluation of thecondition of the surface area of goods was missing.For these reasons an evaluation was established, which corresponds with the finished goods and which contains themost important characteristics. The explanation for implementing the newly developed fabric evaluation is pointed outwithin.

2.3.2. Criteria for the evaluation – 4/06

This fabric evaluation is meaningful in comparing textiles between each other. The evaluation of a textile depends onthe requirements in the finished goods and therefore, the implementation of such an evaluation should be consideredup front. It is possible to provide evaluations tailored for the finished goods.

2.3.2.1. Sampling

The ideal size of the sample to be evaluated is 1m x 1m. This size embodies a reasonable compromise, to representa sufficiently large space, however a still manageable surface area. The fabrics frequently lack on sufficient length,however, with this method also longer sections can be viewed on the fabric inspection table.The sample size A3 and smaller, was clearly rated too small by the evaluation team, because the range withinevaluations is getting wider.In each case the test samples are taken out of the centre part of the fabric course, therefore the fabricated textile areamust have a minimal length of 10m.

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Two test specimens are cut per position, one serves purely for the optical evaluation and the other one for theevaluation of the fabric-hand. The selected fabric sections must be representative; they may not contain an

accumulation of fabric defects.To examine the surface of the goods, a fabric section of the size DIN A4 is prepared for each position.

2.3.2.2. Colour of the test specimen

The surfaces area, which is being judged, must always be dyed. A blue test-colour defines the best. Raw or whitesamples are not suitable for an acceptable evaluation, since those glare the eyes. Also a raw sample does notcorrespond to an actual situation, because the yarns as well as the surface area react to the dyeing process verysensitive and in different ways.

2.3.2.3. Reference pattern

For the evaluation of surfaces with several variations, the technologist should always include a reference-pattern withan anonymous designation for the examiners. This reference pattern must be recorded in the evaluation form.

2.3.2.4. Group of patterns

When a project contains more than five pattern variations, the technologist must divide the many variants intomeaningful groups of maximum five patterns.For the most part “less is more “.This allocation into groups must be registered in the evaluation form at this point.

2.3.2.5. Evaluation forms

The general data and most important properties are registered in the head of the form. If not all data of the settingsare known, or if uncertainties exist, then these have to be determined in the textile laboratory by utilizing theevaluation sheet.

The visual evaluations of an area-measured surface are registered into the appropriate columns of the form. Thecolumns contain the following test parameters, whereby the terms of the score are already defined.

• Evenness, keenness and imperfectionsScore definitions 1 = very low

2 = low3 = middle4 = intense5 = very intense

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• With dyed areas, the colour intensity is evaluatedScore definitions 1 = lustre

2 = semi dull3 = dull

• By fabrics with patterns, the contrast is evaluated additionallyScore definitions 1 = sharp

2 = floating3 = hazy / blurred

• Covering factorScore definitions 1 = opaque

2 = low translucent3 = semi translucent4 = high translucent

5 = transparent• The fabric-hand “softness”Score definitions 1 = very soft

2 = soft3 = middle4 = harsh5 = very harsh

• The fabric-hand “stiffness”Score definitions 1 = very flexible

2 = flexible3 = middle4 = stiff

5 = very stiff• The fabric surface “fuzzy /hairiness”Score definitions 1 = very low

2 = low3 = middle4 = intense5 = very intense

An evaluation from is available for the normal fabrics, the Gedrebe and for the knitted fabric.

2.3.2.6. Evaluation personnel

Three authorized persons, usually out of the textile laboratory, should perform the surface evaluations. The evaluationpersonnel must go through the evaluations one after the other, since as a group, the evaluators could cross influenceeach other. The evaluations are based on a defined scale of scores (see previous point).During the evaluation the scores are registered in the appropriate form. An average value per column is formed fromthe combined results of assessment personnel.

• The scores may not be changed after the evaluation, except with extreme values, the person in charge forthe surface evaluation must decide.

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2.3.2.2. Criteria for fabric inspection table

The most important aid is a functional fabric inspection table. The fabric inspection table consists of a frame and theinspection table.The fabric inspection table should represent a „combination apparatus“, with which the surface area of the materialscan be examined as well as the transparency and the Fabric hand can be judged.

The criteria to conduct an appropriately optimal evaluation are listed below.• The frame of the inspection table must be inclinable, just like the principle of a blackboard,• the table must accommodate two samples of 1m each, for side by side evaluation,• the samples are fixed to the inspection table with Velcro tape,• the height of the inspection table axis should be adjustable (to accommodate the size of the examiner),• the luminous intensity of the lighting source must be selectable, to adjust for the evaluation of surface view or

transparency,

• for surface viewing, the position of the light source has to be movable,• a large empty space of at least 3m must be available in front of the fabric inspection table.

The light fixture on the inspection table is of high importance. The illumination inside of the table may not form shadeson the diffusion screen and for the surface viewing, it must illuminate the fabric surface evenly.

The location of the inspection table must be flexible. The setup should provide for daylight as well as for dark roomviewing conditions, to achieve optimal evaluation. This is provided on the first floor of the Trainings Centre for daylightand in the basement for the dark room conditions.

2.3.2.3. Varieties of evaluation

In transparency In transparency, the examination requires an illumination from within the inspection table. The size of the surface areathat can be illuminated must be sufficient to accommodate two samples hanging next to each other. Whereby the lightsources within the table, must illuminate very evenly without forming any shadows.The brightness of the illumination must be adjustable. Consideration has to be given, that the room illumination willnot interfere with the fabric transparency

In surface view In surface view, a very demanding lighting condition is required for examination. In most cases the daylight is theideal evaluation light. However the daylight behaves rarely even over a longer time span and often is not reproducibly.Therefore an additional external, even illumination of the test specimen is required - the so-called ambient light – as arequirement for surface viewing.

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Various evaluations Additional to the fabric appearance and imperfections

• the fabric-hand and• the covering factorare evaluated at the fabric inspection table with the appropriate angle of slope.

The surface area of goods is examined basis on an A4 sample, away from the inspection table.

Transparency with background The evaluation of fabrics against a white or black background on the inspection table is considered as specialevaluations.

2.3.3. Evaluation guideline - 4/06

For each distinct evaluation, the sample must be evaluated by at least three predetermined persons, whereby thepersons must originate from the evaluation team. The procedures are described under the following points, to simplifythe evaluation process.The evaluation form contains the columns with the respective evaluation criterion to be judged. The scale of scoring isillustrated on the form for the fabric (Gedrebe is always included under fabric), or knitted fabric for the evaluationunder the respective column.

2.3.3.1. Appearance of goods and imperfections

The ideal height of the inspection table is, when the midpoint of the sample height is on eye level and can be judgedwithout body distortion. The fabrics are attached to the inspection table, which is at an angle of less then 50° to thehorizontal axis.The test fabrics are fastened to the upper edge of the inspection table by means of a Velcro tape, so that they areevenly distributed and without folds or waves for evaluation on the inclining surface.

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When evaluating transparency restrained room illumination and without daylight.When evaluating in surface view constant daylight or so called ambient light, whereby the room illumination

has to be switched off.

Appearance of goods

Evenness:The first visual impression is here decisive. The overall impression is to be evaluated over the complete fabric patternwithin a short time. Position yourself at a sufficient distance to the object and in a natural pose, without headmovement.The fabric section is to be judged like a picture in the museum, first impression, overview, in wide angle, for a shorttime, unlike the objective testing of a UT4 device, but open-minded and subjectively.

Keenness:How obvious are un-even areas in the fabric noticeable. In “keenness”, an area of an accumulation of thin- and thickplaces is portrayed. The thin places show up much more pronounced and particularly in transparency view, they aremore recognizable to the human eye, therefore the designation „keenness“.

ImperfectionsThe evaluation of imperfections is the complete opposite versa the appearance of goods. Here the imperfections are judged with the utmost care, from close up and substantially longer time frame.

Thin placeAll thin places in the fabric are considered, independently of their length and/or size.

Thick placeMass increases of all kinds, regardless of length and size.

NepsNo assessment is made according size, simply consider all neps.

Caution With frequent appearance of imperfections of certain length or size-class, please note on the evaluationform under remarks.

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2.3.3.2. Covering factor

To evaluate the covering factor, it’s necessary to place a contrast underneath the fabric, i.e. a white background witha black cutout. The fabrics are draped on top.The more distinct the transitional contrast is from black to white on the woven /knitted fabric, the lower the coveringfactor of the fabric. That means the more diffused this line, the higher the covering factor.

2.3.3.3. Fabric-hand

This evaluation is performed on the inspection table again, whereby this is adjusted upright, to allow the fabric sampleto hang freely.Two test samples are positioned vertically next to each other in such a way, that the area-measured material canreturn into its initial position after grabbing, to recover its shape. On one hand the softness and on the other hand thestiffness of the fabric is evaluated.

To the fabric-hand „softness “ On one hand the softness and on the other hand the stiffness of the Textilearea-measured material are evaluated. Whether a fabric exhibits a soft orrather a harsh hand, can be establish through touch with the hands.

The definition for the score ranges from very soft to very harsh in fiveincrements.

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To the fabric hand „stiffness “ To evaluate fabric stiffness, one must - always with the same hand - reach

into the fabric from underneath. According to the resistance and the numberof folds developed, one can establish, which of the fabrics has whatstiffness.

The definition for the score ranges from very flexible to very stiff in fiveincrements.

2.3.3.4. Surface-area of goods

To evaluate the surface area of goods, test samples withthe size of DIN A4 are prepared.They are placed next to each other (maximum numberof four) on a special board with a width of 60 cm, whichis set at an angle of 45° to a horizontal table area.

For a reliable evaluation, the upper edge must be shaped „knife like“ to develop a sharp break in the surface of thefabric. By examining the upper edge of the fabric, along the intended break line, a statement concerning hairiness ofthe fabric can be made.No more then 3..4 samples should be placed next to each other.

To the evaluationOne can easily assess whether a surface area is fuzzy or less fuzzy. Depending on the intensity of the yarn hairiness,a pronounced “furry“, or a less hairy surface develops. One must proceed as described above to methodicallyexamine this.If none, or very few hairs stand out, the fabric goods are less fuzzy. When many fibres are raised, the goods appearconsiderably fuzzy. Again the scores are defined within a range of five increments, from very intense to very low hairiness.

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2.3.3.5. Obvious fabric defects

All fabric defects must be considered in the evaluation. The obvious defects have to be noted in the evaluation form.Please indicate the type, the number and if possible, the reason of the defects.In general, everything particularly obvious should be noted during the evaluation, even if it doesn’t appear relevant atthe moment. This can be recorded under the column; noticeable problems / fabric or knitted fabric defects.

2.3.3.6. Example of fabric evaluation - 4/06

An evaluation of an area-measured material is depicted in the following example.This form (table) corresponds to the master form for evaluating normal woven fabrics. Three individuals performedthis evaluation and in conjunction, the averages were established and entered into the evaluation form.This form is based on the version Nov. 2005

Finished goods: Yarn Area-measured ma terial Date Name / Initials

22045 Material PES / CO 10.11.2005 A.W.

Positions CA1 - CA4 Count warp /filling

P.T Spin. System conventional / COM4 Fabric binding

Surface area

of goods

Position No. Evenness Keenness

Intensity

of colour

(dyed)

Contrast

(pattern)

Thin

places

Thick

placesNeps Softness Stiffness Fuzzy/ Hairiness

1: very low 1: very low 1: opaque 1: very soft 1: very flexible 1: very low

2: low 2: low 2: low translucent 2: soft 2: flexible 2: low

3: middle 3: middle 3: semi translucent 3: middle 3: middle 3: middle

4: intense 4: intense 4: highly translucent 4: harsh 4: stiff 4: pronounced

5: very intense 5: very intense 5: transparent 5: very harsh 5: very stiff 5: very pronoun.

CA1 4 2.7 2.7 2.7 3.3 2.7 3.7 3.0 2.7

CA2 5 2.7 3.0 2.7 3.7 4.3 3.0 2.0 4.0

CA3 6 2.7 2.3 3.0 4.0 3.0 1.4 1.7 1.4

CA4 7 4.0 4.0 4.3 3.0 3.3 3.7 3.7 4.0

Position Covering factor

CA1 1 very good 2.7

CA2 2 good 4.3

CA3 3 acceptable 3.0

CA4 4 sufficient 3.3

5 insufficient

CA2: Yarn piecing approx. 3.0 cm long; Fibre fly appears as thick place 2x

CA3: -

CA4: Short thick place 0.5 - 1.5 cm long

Noticeable problems / Fabric defects

CA1: Yarn piecing approx. 3.0 cm long; Fibre fly elevated nep level; One piecing in direction of warp

3.0 1.5

3.8 3.8

2.9 3.1

3.0 3.0

Score

Assessment score Appearance / Imperfections Fabric hand / Surface area of goods

Covering factor

Fabric hand

Scoring /

Assessment

Intermediate score of evaluation

Criteria Appearance of goods Imperfections

Project no.

Customer

Ordering Party

Setting [Warp/Filling per cm]

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2.3.3.7. Comparison of evaluations

A comparison of the preceding evaluation method and the new evaluation 4/06 is illustrated in the following table.

PositionResult of the old evaluation

method RieterResult of the new evaluation

method 4/06

CA1 4 3.0

CA2 6 3.0

CA3 7 2.3

CA4 7 3.8

When comparing the results of the existing evaluation method at Rieter Machine Works and the recently establishedfabric evaluation version 4/06, the following contradiction develops.The best position CA3, with the score 2.3, received one to the worst evaluation within the overall score under Rieter.The reason lies in the fact, that the surface area of goods and the fabric hand, were not considered in the existingevaluation, although essential for the assessment of the fabric quality.

2.3.3.8. Forms

The master forms to record the evaluations are partitioned as follows• Normal fabric

• Gedrebe• Knitted fabric

The evaluation forms are available as Excel files in the document folder.

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3. TEXTILE UNITS AND DEFINITIONS

3.1. Yarn count system

The Weight Systemtex

m

l=

g

km

dtex for fibrestex for yarnktex for slivers

The unit tex reveals how many Grams per1000 m, a product weighs.

= usw.,kg

km

,mg

mm

,g

m

m

l

Nm

i.e. Nm 10 defines, that 10 m Material weigh

1 Gram.

The Length System

NeHank (

pound (lbc =

840 yd)

)

i.e. Nec 60 defines, that 60 Hank ( 840 yd)

weigh 1 Pound (lb)

Conversion Nm

tex tex

Ne Nm Nm Ne

=

= ⋅ = ⋅

1000

0590541 169336

Ne =590.541

. .

dtex g in g in Micronaire= ⋅ =µ µ/ , ( /0 394 )

3.2. Classification of cotton

Length [Inch]

13/16" to 15/16"31/32" to 11/8"15/32" to 1 1/4"19/32" to 13/8"113/32" to 13/4"

short staplemedium staplemedium to long staplelong stapleextra long staple

Fineness [Microgram/inch =µg/in] =Micronaire

below 3,03,0 - 3,94,0 - 4,95,0 - 5,9

6,0 and higher

very finefineaveragerather coarse

coarseBreaking Strength

[Pressley 1000 lbs/inch2]

93 and higher87 - 9281 - 8675 - 8070 - 74below 70

excellentvery strongstrongaveragepassableweak

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Maturity[% Causticaire]

82% and higher76% - 81%

70% - 75%below 70%

maturemedium-mature

immaturevery immature

Uster Statistics 5% - 10%10% - 25%25% - 50%50% - 75%75% - 95%

Very goodgoodaveragebelow averagemuch below average

Shirley-Analyse[Rieter Standard]

- 1.2% Trash1.21% - 2.0%2.01% - 4.0%4.01% - 7.0%7.01% and more

Very cleancleanaveragedirtyvery dirty

3.3. Yarn break standards

Yarn breaks / 100 Spd/h or R/h Yarn break /100 h =hSpd Nohtime Run

break Yarn

/../

1000

×−×−

CO combed Ringyarn

CO carded Ringyarn

Long staple100%

Rotor yarn

12

2348

14

2858

38

75150

20

3055

good

averagepoor

3.4. Spinning limits

Spinning Limit Number of Fibres Ø =texFibre

texYarn

Long staple Material (Wool and Blends)Staple fibre 3.3dtex / 50-60-80mm

Staple fibre 1.3-1.7dtex / 38-40mmCotton – Ring yarnCotton – Rotor yarn

40 Fibres Ø55 Fibres Ø

70 Fibres Ø70 – 80 Fibres Ø120 – 150 Fibres Ø

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3.5. Climatic guidelines

Room conditions in the combing preparation = conditions on the comber

Temperature Humidity

Degrees Celsius relative % Water content g/kg

Guideline 24 50-52 8-12

Range of Short term (Month) ±2 ±3

operation Long term (year) 22-28 45-55

With high stickiness of the Fibre material = low absolute water contentWith low stickiness of the Fibre material = high absolute water content

3.6. Quality values

A% Mean deviation of the count from the set value as determined with reference to adefined duration (almost shift)

U% count variation = out-of-dateCV U% . %= ⋅125

CV% Coefficient of variation of evenness

Meanvalue=x deviationStandards

=

= x

sCV

CVL x m Coefficient of variation of count for the set cut length xx = 1m, 3m, 10m, 100m, or yards

Sliver count spectrogram Graphic depiction of periodically occurring unevenness(Peak) = Poisson distribution

Range or wavelength, which the data system can measure: a few cm to several100m

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3.7. Basic conversion charts

Name of the unit Symbol Metric unitLength units 1 inch

1 foot (=12 in)1 yard (= 3 ft)1 mile

inftyd

2.54 cm0.3048 m0.9144 m

1609.344 m

Area units 1 square inch1 square foot1 square yard

sq insq ftsq yd

6.4516 cm2

929,030 cm2

0.836127 m2 Mass units 1 grain

1 ounce

1 pound (= 10 oz)

groz

lb

0.064799 g28.3495 g

0.453592 kgForce units 1 ounce-force

1 pound-force (= 16 ozf)ozflbf

0.278014 N4.44822 N

Pressure units 1 pound-force per square inch1 pound-force per square foot

lbf/in2

lbf/ft2

6894.76 N/m2 47.8803 N/m2

Tenacity 1 kilogram-force Nec

1 gram-force per denier

1 kgf Nec

1 gf/den

0.579 cN/tex8.838 cN/tex

Temperature 1° Fahrenheit °F

[ ]C F

°−°8.1

32

1° Celsius °C [ ] F C x °+° 328.1

°F 50 60 65 70 75 80 85 90 100°C 10 16 18 21 24 27 29 32 38

Sliver weight from metric to imperial units

g/m 20 30 40 50 55 60 65 70 75 80 85 90 100gr/yd 282 423 564 706 776 847 917 988 1058 1129 1199 1270 1411

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3.7.1. Textile conversion formulas

texα mα eα

texα -- mα ×6.31 eα ×957

mα 6.31

texα -- eα ×3.30

eα 957

texα

3.30

mα --

from

to

T/“ = Nee×α

T/m = Nmm×α

T/m =tex

texα

T/m = 4.39/"×T

T/“ = 0254.0/ ×mT

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tex dtex den yard

grains

inch

g Nm ton Necot

L Ne

tex -- 1.0×dtex 111.0×den 86.70× yard

grains

4.25

inch

g µ Nm

1000

ton Necot

5.590

L Ne

5.1653

dtex 10×tex -- 11.1×den 6.708× yard

grains

54.2

inch

g µ

Nm

10000

ton Necot

4.5905

L Ne

16535

den 9×tex 9.0×dtex -- 7.637× yard

grains

82.2

inch

g µ

Nm

9000

ton Necot

9.5314

L Ne

14882

yard

grains

86.70

tex

6.708

dtex

7.637

den --

4.1801

inch

g µ

Nm

1.14

ton Necot

33.8

L Ne

33.23

inch

g 4.25×tex 54.2×dtex 82.2×den 4.1801×

yard

grains --

Nm

25400

ton Necot

15000

L Ne

42000

Nmtex

1000

dtex

10000

den

9000

yards

grains

1.14

inch

g µ

25400 -- 693.1cot ×ton Ne 605.0× L Ne

ton Necot tex

5.590

dtex

4.5905

den

9.5314 yards

grains

33.8 inch

g µ

15000 693.1

Nm --

8.2

L Ne

L Ne tex

5.1653 dtex

16535

den

14882 yards

grains

33.23 inch

g µ

42000 605.0

Nm 8.2cot ×ton Ne --

w Ne tex

5.885

dtex

8858

den

3.7972 yards

grains5.12

inch

g µ

22500 13.1

Nm 5.1cot ×ton Ne

87.1

L Ne

Y.S.W.tex

7.1937 dtex

19377 den

17439 yards

grains

34.27 inch

g µ

49218 516.0

Nm 28.3cot ×ton Ne 172.1× L Ne

from

to






Technology Handbook

4. TEXTILE TESTING

Common test parameters for fibre and yarn testing / sorted by instruments

4.1. Parameters for fibre testing / sorted by instruments

4.1.1. AFIS – Neps, Length & Trash

4.1.1.1. AFIS-N (Neps)Weight [g] Sample weightNep [µm] Average nep sizeNep [Cnt/g] Number of neps per gramSCN [µm] Mean Size of Seed Coat NepsSCN [Cnt/g] Number of Seed coat neps per gram

4.1.1.2. AFIS- L&M (Length and Maturity)N By numberW By weightL (n/w) [mm / in] Mean Fibre lengthL (n/w) CV [%] Coefficient of variation of Fibre lengthSFC (n/w) [%] Short Fibre Content, fibres that are shorter than ½ inch or 12.7 mmUQL (n/w) [mm / in] Upper Quartile Length = Fibre length, that 25% of fibres have – 25% are

longer than this value

5% (n) [mm / in] Fibre length, 5% are longer than this value (by number)2.5% (n) [mm / in] Fibre length, 2.5% are longer than this value (by weight)Fine [mtex] Fibre finenessIFC [%] Immature Fibre ContentMat Ratio [ ] Maturity Ratio

4.1.1.3. AFIS- L&D (Length and Diameter)D (n) [µm] Fibre diameter (sometimes in mm!)D (n) CV [%] Coefficient of variation of diameter

4.1.1.4. AFIS-T (Trash)Total [Cnt/g] Number of all trash particlesMean Size [µm] Mean trash particle sizeDust [Cnt/g] Dust particles per gram (< 500 µm)Trash [Cnt/g] Trash particles per gram (> 500 µm)V.F.M. [%] Visible Foreign MatterT.F.M. [%] Total Foreign Matter = visible trash content

Same as VFM (dep. of software version)

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4.1.1.5. AFIS-S (Fibre length for man made fibres)L (n) [mm / in] Mean fibre length

L (n) CV [%] Coefficient of variation of Fibre lengthM-L (n) [mm / in] Mono Length = Cut length of fibresM-L (n) CV [%] Coefficient of variation of Mono Length% short X [%] Percentage of fibres that are shorter than the length X (selectable)

Y % [mm / in] Fibre length that Y % of fibres exceed (selectable)D (n) [µm] Mean fibre diameterD (n) CV [%] Coefficient of variation of fibre diameterFine [mtex / den] Fibre finenessFine CV [%] Coefficient of variation of fibre fineness

4.1.2. Almeter 101 - Capacitive fibre length measurementN By number -> Hauteur in woolen areaW By weight -> Barbe in woolen areaML (N) [mm] Mean Fibre length by numberCV (N) [%] Coefficient of variation of fibre length by numberSF (N) <12.5mm

[%] Percentage of fibres that are shorter than 12.5 mm (by number)

L (N) 1% [mm] Fibre length by number that 1% of fibres exceedML (W) [mm] Mean fibre length by weightCV (W) [%] Coefficient of variation of fibre length by weightSF (W) < 12.5mm

[%] Percentage of fibres that are shorter than 12.5 mm (by weight)

L (W) 25% [mm] Fibre length by weight, that 25% of fibres exceed – Classer’s Staple

4.1.3. Single Fibre Measurement – Manual StapleMax. Fibrelength

[mm] Longest fibre in mm

Mean Fibrelength

[mm] Mean fibre length in mm

CV Fibre length [%] Coefficient of variation of fibre length

4.1.4. FCT – Stickiness, Neps, TrashStickiness [1/g] Number of sticky points per gramNeps [1/g Number of neps per gramSCF [1/g Number of seed coat neps per gram (Seed Coat Fragments)Trash [1/g Number of trash particles per gramCV Neps [%] Coefficient of Variation on Neps per gram

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Technology Handbook

4.1.5. FQT – Stickiness, Neps, Trash, FinenessMic [µg/inch²] Micronaire

Fin [mtex] Fibre fineness in mtexMat [ ] MaturityStickinessCnts/gr

[1/g] Number of sticky points per gram

StickinessGrade

[ ] Grading of sticky points (combination of number and size)

Neps Cnts/gr [1/g] Number of neps per gramS.C.NepsCnts/gr

[1/g] Number of seed coat neps per gram

S.C. NepsArea/gr

[ ] Area of seed coat neps in mm² per gram

Trash Cnts/gr [1/g] Number of trash particles per gram

Trash Area/gr Area of trash particles in mm² per gramDust Cnts/gr [1/g] Number of dust particles per gram

4.1.6. Fehling – Chemical determination of stickinessHoneydew [mg/100g] Sugar content in mg

4.1.7. Graf SCT- Stickiness ThermodetectorNumber ofSticky points

[ ] Number of counted sticky points per measurement (per 2.5g)

4.1.8. H2SD – High Speed Stickiness Detector - StickinessTotal [1/g] Total count of sticky points per gram (all sample sizes)Small [1/g] Number of sticky points of the size 1.7 - 9.0 mm²Medium [1/g] Number of sticky points of the size 9.0 - 18.0 mm²Large [1/g] Number of sticky points larger than the size 18.0 mm²

4.1.9. HVI – High Volume Instrument – Tenacity, Fineness, Color

4.1.9.1. HVI -910 (ICC-cal) Fibre length measurement, Bundle strength

Len 1 orSL 50% [mm/in] 50% span length: Fibre length, that 50% of fibres exceed

Len 2 orSL 2.5%

[mm/in] 2.5% span length: Fibre length, that 2.5 % of fibres exceed~ Classer’s Staple

Unif [%] UR: Uniformity Ratio, Relation of Len1/Len2 *100 = UR - (Value around 50)Strength [gf/tex] Breaking force of the fibre bundle divided by fibre fineness on ICC levelElong [%] Breaking elongation of fibre bundle

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Technology Handbook

Additional values for HVIAmount [ ] Parameter describing the optically measured number of fibres in the bundle

at the time of breakWork peak [J] Work to peak (area below stress-strain-curve up to peak point)Work Tot [J] Work total = complete area below stress-strain curveCrimp [%] Fibre crimpModulus [N] Material constant describing the tensile behavior of the fibre bundleS.F. or SFI [%] Short Fibre Index (calculated)SCI [ ] Spinning Consistency Index – Calculated out of various parameters by

multiple regression. = Value for raw material and spinnabilityCSP [ ] Count Strength Product – theoretical skein strength of an Ne 16 yarn

4.1.9.2. HVI -910 (HVI-cal) Fibre length measurement, Bundle strengthLen 1 [mm/in] ML: Mean Length - mean fibre lengthLen 2 [mm/in] UHML: Upper Half Mean Length = Mean Length of the longest half (50%) of

fibresUnif [%] UI: Uniformity Index, Relation of Len1/Len2 *100 =UI - (Value around 80)Strength [gf/tex] Breaking force of the fibre bundle divided by fibre fineness on HVI levelElong [%] Breaking elongation of fibre bundle

4.1.9.3. HVI -920 MicronaireMic [µg/inch] Micronaire – Parameter describing fibre fineness and maturity (via air flow

determined)

4.1.9.4. HVI -930/35 Color and TrashRd [ ] Reflectance of the fibres, higher Rd values mean a higher color grade+b [ ] Yellowness of the fibres (Nickerson/Hunter Scale)C-G [ ] Color-Grade= Classing according given standard (e.g. US-Upland, US-Pima

or individual user specific standard)Area [%] Area of the sample covered with trash particlesCnt [ ] Number of trash particles on surfaceTrash / Leaf [ ] Trash-Grade= Classing of trash content. Higher value -> more trash

particles

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Technology Handbook

4.1.9.5. HVI - Spectrum (only HVI - Calibration)Micronaire [µg/inch] Micronaire – Parameter describing fibre fineness and maturity (determined

via air flow)Maturity [ ] Maturity of cotton (calculated with algorithm)Len [mm/in] UHML: Upper Half Mean Length = Mean Length of the longest half (50%) of

fibresAmt [%] Parameter describing the optically measured number of fibres in the bundle

at the time of breakUnf [%] UI: Uniformity Index, Relation of Len1/Len2 *100 =UI - (Value around 80)SFI [ ] Short Fibre Index (calculated)Str [g/tex] Breaking force of the fibre bundle divided by fibre fineness (Mic) on HVI

levelElg [%] Breaking elongation of fibre bundleRd Reflectance of the fibres, higher Rd values mean a higher color grade

+b Yellowness of the fibres (Nickerson/Hunter Scale)C Grade Color-Grade= Classing according given standard (e.g. US-Upland, US-Pimaor individual user specific standard)

Tr Cnt [Cnt] Number of trash particles on surfaceTr Area [%] Area of the sample covered with trash particlesTr Area Trash-Grade= Classing of trash content. Higher value -> more trash

particlesMoist [%] Moisture content of measured cottonSCI [ ] Spinning Consistency Index – Calculated out of various parameters by

multiple regression. = Value for raw material and spinnabilityCSP [ ] Count Strength Product – theoretical skein strength of an Ne 16 yarn

4.1.10. MDTA3 / ITV – Trash contentLint content [%] Percentage of lint fibres referring to whole sample after testingTrash content [%] Percentage of removed trash particles (>500 µm)Dust content [%] Percentage of dust particles (< 500 µm)Fibre Fragments [%] Percentage of fibre fragments (250 - 500 µm)

4.1.11. NATI

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Neps [Total] [Cnt] Number of all neps of all sizes (≠ Neps per gram,depends on sample size!)

Neps[ > 0.5 mm]

[Cnt] Number of neps with the size of 0.5-0.7 mm(depends on sample size!)

Neps

[ > 0.7 mm]

[Cnt] Number of neps with the size of 0.7-1.0 mm

(depends on sample size!)Neps[ > 1.0 mm]

[Cnt] Number of neps with the size larger than 1.0 mmdepends on sample size!)

Trash[Total]

[Cnt] Number of trash particles(depends on sample size!)

Trash[> 0.25 mm]

[Cnt] Number of trash particles with the size of 0.25 -0.5 mm(depends on sample size!)

Trash[> 0.5 mm]

[Cnt] Number of trash particles larger than 0.5 mm(depends on sample size!)



Technology Handbook

4.1.12. Parallex - Parallelism in SliverL x [mm] Useable fibre length in mm

4.1.13. Pressley – Bundle StrengthPressley-Index [P.I.] Bundle strength in lbs per bundle weight in mgPressley [1000 lbs/inch²] Specific bundle strength per square inch

4.1.14. Rothschild – Adhesive length (Tenacity)Adhesive length [m] Resistance of the material whilst drafted. Length at which the sample would

tear below its own dead weight. [g/ktex]Adhesivestrength

[cN] Mean Force during drafting

CV [%] Variation of adhesive length

4.1.15. Shirley / Selecter – Trash content of raw cottonStart Weight [g] Sample weight before testingLint content [%] Percentage of LintTrash content [%] Percentage of TrashShort fibres anddust

[%] Percentage of fibre fragments and dust

Cage loss [%] Loss between the weight before and after testing

4.1.16. Shirley FMT – Maturity via AirflowMaturity [ ] Maturity of cotton fibresPM [%] Relation of lumen to diameter gives percent maturity

4.1.17. Stelometer – Fibre Bundle StrengthTenacity [g/tex] Breaking force of the fibre bundle divided by fibre fineness on ICC levelElongation [%] Breaking elongation of fibre bundle

4.1.18. UT3 / UT4 – Capacitive Sliver and Roving UnevennessCVm with 25m/min

[%] Coefficient of variation of mass unevenness

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Technology Handbook

4.1.19. Vibrojet – Single fibre fineness and tenacityFineness [dtex] Fibre fineness in dtex

Strength [cN/tex] Fibre tenacity in cN/tex (Force divided by fineness)

Force [cN] Breaking force of single fibres

Elongation [%] Fibre elongation before break

Work done toBreak

[cN.cm] Work to break (area below stress-strain-curve up to break point)

Ten @ x % [cN/tex] Material constant on elongation behavior at e.g. 10% elongationYoung-M. [cN/tex] Young Modulus (Specific force at a certain point)

4.1.20. Vibrotex – Single fibre crimpRemoving Crimp [%] Removing crimp is length extension divided by straightened length

RecoveringCrimp

[%] Fibre length difference between extension at 1 cN/tex and extension at 0.01cN/tex divided by straightened length

Stability of crimp [%] Crimp stability is ratio of recovering crimp and removing crimp

Mk / Md Modulus values of crimp

Number ofbows [1 / cm] Number of crimp bows per cm

Min Minimal value

Max Maximal value

4.1.21. Vibroskop / gravimetrical fineness determinationFineness [dtex / mtex] Fiber fineness in dtex or mtexCV [%] Coefficient of variation of fibre fineness

4.1.22. Zweigle – Twist in RovingClamp length [cm] Length that is clamped for twist determinationTwist [m-1] Turns of twist per 1 meterCV [%] Coefficient of variation of twist measurement

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Technology Handbook

4.1.23. Zwick – Tenacity in FabricsChain Determination of values in chain direction

Weft Determination of values in chain directionClampingdistance

[cm] Clamping distance for tenacity determination

Force [cN] Max Force at fabric breakTenacity [cN/tex] Max Tenacity (Force per fineness) at fabric breakCV [%] Coefficient of variationElongation [%] Elongation at fabric breakCV Elongation [%] Coefficient of variation of Elongation

4.1.24. Zwick – Adhesion Length (Tenacity)Clamping

distance

[cm] Clamping distance for tenacity determination

Force [cN] Max Force at BreakTenacity [cN/tex] Max Tenacity at BreakCV [%] Coefficient of variationElongation [%] Elongation at BreakCV Elongation [%] Coefficient of variation of ElongationAdhesive Length [m] Resistance of the material whilst drafted. Length at which the sample would

tear below its own dead weight. [g/ktex]

4.2. Parameters for yarn testing / sorted by instruments

4.2.1. Autosorter – Yarn finenessYarn count [Ne/tex/Nm] Value in Ne [Hanks/lb = 768 m / 453 g], in tex [g/1000m] or in Nm [m/g]CV t [%] Coefficient of variation between the different yarns

4.2.2. OPTRA- optical trash content in yarnParticles /1000m

Sum of particles in the yarn of all size per 1000 m

Class A [0.05 - 0.3 mm²] Number of Trash particles in the size of Class A

Class B [0.3 - 0..7 mm²] Number of Trash particles in the size of Class BClass B [0.7 - 3 mm²] Number of Trash particles in the size of Class C

4.2.3. Reutlinger Webtester - Simulation of yarn abrasion at the weaving loomTours untilbreak x

[U/min] Number of tours until yarn no. x. breaks (x = 1-9)

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Technology Handbook

4.2.4. Uster Classimat – Yarn faultsFault / 1000 m Length of fault in cm Change of mass in %

A1 < 1 cm + 45 to- +100 %A2 +100 to +150 %A3 +150 to 250 %A4 +250 to 400 %

B1 1 to 2 cm +45 to +100 %B2 +100 to +150 %B3 +150 to 250 %B4 +250 to 400 %

C1 2 to 4 cm +45 to +100 %C2 +100 to +150 %

C3 +150 to 250 %C4 +250 to 400 %

D1 4 to 8 cm +45 to +100 %D2 +100 to +150 %D3 +150 to 250 %D4 +250 to 400 %

E < 8 cm > 100%F 8 to 32 cm +45 to +100 %G > 32 cm +45 to +100 %

H1 8 to 32 cm -30 to -45%H2 8 to 32 cm -45 to -75 %

I1 > 32 cm -30 to -45 %I2 > 32 cm -45 to -75%

4.2.5. Uster Tensojet - TenacityB-Force [cN] Breaking force= tensile force measuredTenacity [cN/tex] Breaking force divided by the yarn count in texCV Fmax [%] Variation of the breaking forceB-ForceElongation E

[%] Breaking elongation = elongation at maximum force

CV B-Force E [%] Coefficient of variation of elongationB-Work [cN.cm] Work to Break = work at breaking force (area below the force-elongationcurve to the point of breaking force)

Min values Minimum value of force, elongation, tenacity or work within one test seriesMax values Maximum value of force, elongation, tenacity or work within one test seriesP: 0.01 0.01% of all measurements are below this reported value

(also possible for 0.05%, 0.1%, 0.5% and 1.0%)

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Technology Handbook

4.2.6. Uster Tensorapid / Tensokid- TenacityPretension Force applied to straighten yarn, normally 0.5 cN/tex

Time to break [s] Time elapsed between the start of the measurement and the breakage ofthe specimenB-Force [cN] Breaking force= maximum tensile force measuredTenacity [cN/tex] Breaking force divided by the yarn count in texElongation [%] Breaking elongation = elongation at time to breakB-Work [cN.cm] Work to Break = work at breaking force (area below the force-elongation

curve to the point of breaking force)

4.2.7. CBL Variation of lengthCV 10 m [%] Variation of yarn count at different cut length values, e.g. 10m, or 50, 100,

250, 500, 1000, 2000m

4.2.8. Uster Tester – Evenness Tester

4.2.8.1. Uster Tester 3/4 - CSCVm400 m/min

[%] Coefficient of variation of yarn mass with chosen speed (for Yarns common400 m/min)

Index [ ] Ratio between the ideal and actual evenness of staple fibre strandsCV [%] x m [%] Coefficient of variation for cut lengths of 1, 3, 10, 50 or 100 mImperfections [ 1/ 1000m /

1/1000y ]Number of thin places, thick places and neps at selected sensitivity levels(staple yarns only) per unit length (1000m or 1000y)

Thin places [ ] Number of thin places at selected sensitivity levels, e.g.: -30%, -40%, -50%,

-60%Thick places [ ] Number of thick places at selected sensitivity levels, e.g.: +35%, +50%,

+70%, +100%Neps [ ] Number of neps at selected sensitivity levels, e.g.: +140%, +200% (Ring),

+280% (Rotor), +400%Rel. count [%] Count deviation relating to the length of yarn tested, the mean corresponds

to 100%DR [ ] Deviation Rate

4.2.8.2. Uster Tester 3/4 - OHH [ ] The hairiness corresponds to the total length of protruding fibres divided by

the length of the sensor of 1cm. Therefore without unit.

Sh [ ] Standard deviation of H, related to measurement within 1 cmsh (x) [ ] Standard deviation of H, related to cut lengths of 1,2,10, 50 or 100mh(max)/ h(min) Deviation of the hairiness H (maximal or minimal)

4.2.8.3. Uster Tester 3/4 - FA-ModuleAbs. Count [Ne/Nm/tex] Determination of the yarn count (only with FA-Module)

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Technology Handbook

4.2.8.4. Uster Tester 4 - OMD [g/cm3] Yarn density related to nominal count

2Dø [ ] Two dimensional yarn diameterCV 2D, 8 [ ] Two dimensional optical evenness, cut length 8 mmCV 2D, 0.3 [ ] Two dimensional optical evenness, cut length 0.3 mm (=sensor length)CV FS [ ] Fine Structure = assessment of short wave variations (Difference of CV 0.3

und CV 0.8)Shape [ ] Value that describes roundness of yarn form, ⊕ = 1; ⊂⊃ = 1:2 ⇒ 0.5SD [ ] Standard deviation

4.2.8.5. Uster Tester 4 - OITrash [1/km or

1/1000y ]Number of Trash particles (>500µm) per Unit length

Trash countspec. [1/g] Number of Trash particles (>500µm) per 1 gram YarnTrash size [µm] Size of Trash particles in µmDust [1/km or

1/1000y ]Number of Dust particles (<500µm) per Unit length

Dust count spec. [1/g] Number of Dust particles (<500µm) per 1 gram YarnDust size [µm] Size of Dust particles in µm

4.2.9. Zweigle D301 – Twist measurementT/m [m-1] Twist per 1 m YarnCV% [ ] Variation of yarn twist

4.2.10. Zweigle G565/G566 – Optical hairinessDistance x mm [ ] Numbers of fibres that are protruding out of the yarn body at a certain

length, e.g.: 1, 2, 3, 4, 6, 8, 10 mmS1+2 [ ] Sum of fibres, that have 1 and 2 mmS3 [ ] Sum of fibres, that have are longer than 3 mm

Please note the tested length and check if values are comparedaccording to the same test length (at Rieter per 1m yarn!)

4.2.11. Zweigle G580 - Optische UnevennessYarn diameter [mm] Optical yarn diameterO-CV [%] Optical Coefficient of variation of evennessThin places [1/1000m ] Count of thin places at –30% per 1000mThick places [1/1000m ] Count of thick places at +35% per 1000mNeps [1/1000m ] Count of neps at +50% per 1000m

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Technology Handbook

4.2.12. Zweigle G555 - Stafftester - AbrasionAbrasion [mg/10g Yarn] Yarn abrasion in mg, based to 10g of yarn

Abrasion [mg/1000mYarn] Yarn abrasion in mg, based to 1000m of yarn

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Technology Handbook

3. Opening / Cleaning

1. General information 3

1.1. Introduction 3

1.2. Functions of the blowroom 3

1.2.1. Opening 3

1.2.1.1. The need for opening 3

1.2.1.2. Opening methods 3

1.2.1.3. Observations about fibre opening 4

1.2.2. Cleaning 4

1.2.2.1. The need for cleaning 4

1.2.2.2. Factors influencing cleaning 5

1.2.2.3. Degree of cleaning in the blowroom 5

1.2.3.

Blending 6

1.2.3.1. The need for blending 6

1.2.3.2. Blending options 6

1.2.3.3. Manual feeding 6

1.2.3.4. Automatic feeding 7

1.2.3.5. Bale blooming 7

1.2.3.6. Waste blending 7

1.3. Pneumatic Transportation 8

1.3.1. Transport air and exhaust air 8

1.3.2. Measuring air speed and under pressure 8

1.3.3. Air-conditions in the blowroom 8

2.

OVERVIEW OF PRECEDING PROCESSES 9

2.1. Bale laydown 9

2.2. Fibre feeding 9

2.3. Air requirements of B11 9

2.4. VarioSet cleaning field 10

2.4.2. Definition to be used 10

2.4.3. Results from plant 10

2.4.3.1. Effect of cleaning settings 11

2.4.3.2. Undesirable practices 11

2.5. Bale Laydown and Fibre Feeding 12

2.5.2. General Information 12

2.5.3.

Bale laydown for cotton 12

2.5.4. Bale laydown for man made fibres 13

3. UNIFLOC A 11 14

3.1. Overview of proceeding process 14

3.2. Principal features 14

3.3. Air requirements 15

3.3.2. Undesirable practices 15

3.4. Start up suggestions 15

3.4.1. Take – Off – Roll penetration 15

3.4.2.

Arm lowering steps 16

3.4.3.

Arm traverse speed 16

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3.4.4. Take off roller speed 16



Technology Handbook

3.4.5. Gearing plan A11 UNIfloc 17

3.5. Troubleshooting 18

3.5.1.

Production rate too low 18 3.5.2. Chokes in the fibre transport line 18

3.5.3. Excessive neps in the opened material 18

3.5.4. Trash in the opened material is too high 18

4. UNICLEAN B 11 19

4.4. General Information 19

4.5. Principal Features 19

4.6. Mode of operation 19

4.6.1. Fibre transportation 20

4.6.2. Cleaning process 20

4.6.2.1.

Cleaning intensity 21

4.6.2.2. Relative waste rate 21

4.6.2.3. Cleaning characteristic diagram 21

4.6.3. Waste disposal 22

4.7. Determining the amount of waste 22

4.8. Trouble shooting 23

4.8.1. Neps too high in the material downstream 23

4.8.2. Trash too high after the UNIclean 23

4.8.3. Blockages in the system 23

4.8.4. Waste not being removed from the trash chamber 24

5. UNIMIX B 70 25

6. UNIFLEX B 60 25

7. UNIBLEND A 80 25

8. UNISTORE A 77 25

9. MINIMIX B 3/3 25

10. MIXOPENER B 3/4 25

11. WASTEOPENER B 2/5 25

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Technology Handbook

1. General information

1.1. Introduction

To enable fibre to be transported and stored economically, it must be compressed into bales. It is important thatthe fibre in the bales be allowed to relax before the spinning plant can process it. The pressure must be releasedso that the bales can “bloom”, that is, expand to a stable height. Additionally, the fibre should be given time toabsorb moisture so as to be tough enough to withstand the actions of the subsequent processes.

1.2. Functions of the blowroom

1.2.1. Opening

1.2.1.1. The need for opening

To clean, mix and blend fibres they have to be brought into the smallest aggregate form. The baledmaterial has to be re-opened and fed in small tufts as part of the overall preparation process.Only well opened material can be effectively cleaned,

To enable the fibres to be blended they must be thoroughly opened,

To prepare the fibres for the carding and subsequent operations they must be opened to the pointwhere there will be minimal fibre damage.

1.2.1.2. Opening methods

Opening is usually the first step in the spinning process and includes removal of the fibres from the bale byplucking followed by further opening using pinned cylinders and pinned lift aprons.Opening to a fine degree is normally performed using a feed roll/feed plate combination to restrain the cottonwhilst it is opened into very small tufts by wire wound cylinders, pinned beaters or blade beaters. At each stage ofopening a cleaning operation can be performed.

Cotton has to be opened more than once because trash is removed only from the surface of tufts and multipleopening actions are needed to expose all the trash.

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Technology Handbook

In the blowroom cotton tuft size vary from 5 mg to not more than 150 mg.Throughout the processing steps in the spinning plant the density of the fibre assembly changes in the following

way:

Processing step Density

In the bale 0.30 - 0.70 g/ cm3

In mixer or blender 0.10 g/ cm3

In the sliver can 0.10 g/ cm3

On the roving bobbin 0.25 - 0.35 g/ cm3

Yarn on the bobbin 0.50 g/ cm3

1.2.1.3. Observations about fibre opening

Opening and cleaning machines should constitute a unit, so that the tuft surfaces are cleaned before theyare consolidated in the transportation system,

Opening must be performed effectively with the least number of machines, More than four opening operations, prior to carding, will usually not improve the fibre quality. Excessive

opening increases the number of neps in the cotton. Feeding tufts in “free motion” permits cleaning but no opening Feeding the material in a firmly held state is used for intensive opening. Pins, spikes and teeth open fibres more effectively than bars or slats. The higher the degree of opening in the blowroom, the cleaner can be the material fed to the card and

consequently a cleaner sliver is produced.

The material flow rates through each machine in the blowroom should be adjusted to minimize standing timewaiting to feed the next machine. The machines should run between 85% and 90% of the time

1.2.2. Cleaning

1.2.2.1. The need for cleaning

The trash and other impurities contained in cotton received by the spinner must be removed as completely aspossible to enable an effective spinning operation to be performed at high speeds.The exception to the above statement applies to spinners of novelty yarns and those who spin “low end” very

coarse yarns.

Well-cleaned cotton enables the spinner to,- minimize ends down in spinning,- reduce the weak places caused by trash in the yarn,- spin fine yarns,- produce a more uniform yarn and fabric,- obtain a clean yarn and fabric,- improve downstream processing efficiencies.

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Technology Handbook

1.2.2.2. Factors influencing cleaning

Normally trash is separated from the cotton by centrifugalforce.

The material is moved at high speed in a circular motion. The trash tends to sling out from the fibre surface. Grid bars are provided to allow the trash to escape and

separate from the fibre that passes over the grid bars. The grid bars are adjustable to vary the angle and open

space allowing more, or less trash to be removed.

With an increase in the grid bar opening, there is an increasein the amount of good fibre that goes into the waste with thetrash.

Good fibre in the waste is normally kept to a minimal amount.However, if maximum cleaning is required there will be goodfibre in the waste.

The figures show the amount of trash, fine waste collected atthe filter drum and cotton fibre in the waste. The accumulatedwaste percentage removed is shown as a function of the gridbar angle settings at two beater rotational speeds.

This is the basis of the VarioSet control system developed byRieter for the UNIclean and UNIflex.

New tuft surfaces must be created continuously to facilitate cleaning. Larger, heavier particles are relatively easy to remove, Beating devices tend to break large trash particles making them smaller and more difficult to remove. Large

trash should be removed at the beginning of the cleaning process. For this reason, cotton removed from thebales should be in small tufts for effective cleaning.

Very small trash particles tend to be carried with the cotton in the transport air and it is difficult to obtainseparation. Condensers and fibre separators help with the removal of dust sized particles.

1.2.2.3. Degree of cleaning in the blowroom

The trash content of cotton varies greatly, from 1% to as high as 15%. It is much more difficult to remove trashfrom cleaner cotton than it is from dirty cotton.

The following table shows how much trash is normally removed from cottons with different trash levels.

Original trash content Quantity of trash removed

< 1.2% < 40%

1.3 – 2.0% 40 – 50%

2.1 – 4.0 % 50 – 60%

4.1 – 7.0 % 55 – 65%

>= 7.1 % 60 – 75%

Trash, filter waste and fibreremoved at beater speed 550 rpm

Trash, filter waste and fibreremoved at beater speed 740rpm

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Technology Handbook

As mentioned above some good fibre is lost with the trash. The appearance of the waste indicates the selectivityof the cleaning machine. The cleaning machines have to be carefully set to avoid excessive loss of good fibre but

yet obtain the necessary trash removal action. An analysis of the waste using the Shirley Analyzer can give an objective measurement of the amount of goodfibre in the waste. This can be expressed as a percentage of the waste material or as a percentage of the totalmaterial fed. Care has to be taken to avoid confusion when discussing the “good fibre %” of the waste.

1.2.3. Blending

1.2.3.1. The need for blending

Natural fibres properties vary widely with differences in varieties, countries, regions, climatic conditions, farming

methods, harvesting and storage techniques. Even the fibres in one cotton-boll have varying properties.

The fibres vary in length, fineness, strength, colour and maturity. Plus there are impurities of various kinds in thebaled cotton. It is the goal of the textile plant to produce yarn and fabric that is as uniform as possible and,additionally, the plant tries to run at consistently high levels of efficiency. Care has to be taken to ensurehomogeneous and consistent blending to meet these criteria.

Another factor affecting the composition of the raw materials is cotton price. Every yarn quality has market value.Consequently, some lower quality fibres are used for reducing the spinning costs and enable the spinner tocompete. These special “low cost “ materials usually require careful handling and blending to avoid occasional,unexpected processing problems.

1.2.3.2. Blending options

Blending results in the intimate combination of the various fibres to obtain a homogeneous product. The firststeps in the blending procedure are, mixing the various components and this starts by feeding fibres from thebales in the laydown.

1.2.3.3. Manual feeding

Where the fibre is manually removed from the bales and placed onto a feeding belt or into feeding hoppers, therole of the operator is extremely important. Normally, several bales are fed to one of several hoppers. The hoppershould be fed with thin layers of each bale so that material from every bale is included in the mixing process.Unfortunately, un-supervised operators sometimes feed large portions from only a few bales, which preventsthorough mixing and subsequent blending is compromised. This can result in the blend varying and ultimatelycausing temporary increases in the spinning ends-down rate and possibly fabric defects such as filling bands,streaks or colour shade differences.One benefit of manual feeding is that the operators perform a visual inspection of the cotton and removeundesirable foreign material.

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Technology Handbook

1.2.3.4. Automatic feeding

With automatic machines many operator problems are solved. Once the bale laydown has been correctlyarranged the feeding and mixing can be performed with much more consistency. Care has to be taken to arrangethe bales so that quality waves do not occur due to an accumulation of similar bales in one location in thelaydown. One particular problem can occur when waste bales are placed at the end of the laydown. The machinefeeds some of the waste bale as it comes to the end in one direction and then again feeds waste as it reverses itsdirection of travel.

1.2.3.5. Bale blooming

It is important to remove the bale ties and allow the bales to bloom before the cotton is used. Blooming enables

the cotton to relax and absorb moisture that increases the fibre strength and reduces subsequent fibre damage.

1.2.3.6. Waste blending

There are several kinds of waste produced in spinning plants. Some waste has to be disposed of whereas; otherwaste can be used in small proportions and blended with the normal cotton.

When the waste is in bale form it can be incorporated into the bale laydown, but must be careful placed inthe middle so as to minimize its impact.

Loose waste such as sliver, pnuemafil and roving has to pre opened before it can be mixed with the normalcotton. A waste hopper-feeding unit is used to meter the waste into opening/cleaning line. One problem withthe use of the waste hopper system is that operators can over feed the waste to reduce their job load. Thiscreates an excessively high surge in the percentage of re-usable waste and this frequently leads toproblems in spinning and with yarn quality.

It is also bad practice to abruptly change from feeding one type of waste to a different type. For example, ifthe waste component is changed from combed sliver waste to comber noil, the short fibre content of thecotton in process will change significantly.

Warning: Card flat strips and grid waste should not be re-used. They create excessive yarn defects andprocessing stops.

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Technology Handbook

1.3. Pneumatic Transportation

1.3.1. Transport air and exhaust air

When the fibre passes through a fan there can be fibre damage and excessive nep formation. Additionally, thesystem should be correctly installed to avoid the following problems:

A material handling fan must be used to minimize fibre entanglement. Run the fan as slow as practical to reduce the energy consumption, Avoid excessive high vacuum in the cleaning machines otherwise the trash will tend to stay with the fibre or

waste will be sucked back into the transport air. The exhaust fan must draw more air than the transport fan delivers. Backpressures in air systems usually

create problems.

The ideal fan speed must be determined by tests. After every transfer of cotton from one machine to another, air and fibre must be separated. The duct cross-

section and filter surface must be sufficient to ensure back pressure does not occur.

1.3.2. Measuring air speed and under pressure

To be added later.

1.3.3. Air-conditions in the blowroom

To be added later.

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2. Overview of preceding processes

2.1. Bale laydown

The effective operation of the UNIclean depends upon the condition of the cotton delivered to it. Bales that havenot been allowed to bloom will tend to be fed as lumps rather than tufts and it will be more difficult to remove thetrash.

Problematic bales should be carefully distributed throughout the laydown Multiple assortments reduce the go/stop ratio of the UNIfloc. This means that the instantaneous material

flow rate is much greater than the average rate. The cleaning is performed at the instantaneous rate.

2.2. Fibre feeding

The UNIfloc should feed fibre as consistently as possible. Small tufts, uniform density, with a stop/goratio of 85 to 90%.

Small tufts can be cleaned more effectively than large tufts. However, if the opening by the UNIfloc istoo fine, the over opened material can create problems in air transportation.

The UNIfloc “run-in run-out” program should be set to maintain a consistent fibre flow rate throughoutthe laydown.

2.3. Air requirements of B11

Fibre transportation, waste and dust control

Airflow volume Pressure Condition

Material entry 0.6 - 0.8 m3/s+50 …+150 Pa

(+5 ….+15 mm WC)Continuous

Dust extraction 0.4 - 0.5 m3/s-400…-700 Pa

(-40….-70 mm WC)Continuous

Open Transfer

Waste removal

0.5 m3

/s

-700 Pa

(- 70 mm WC) Intermittent

Material exit 0.6 - 1.0 m3/s-50 …-200 Pa

(-5 ….-20 mm WC)Constant.

Including Supplementary Air

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Technology Handbook

2.4. VarioSet cleaning field

The following illustration graphically shows the amounts of trash and good fibre removed as waste with a range ofcleaning settings.

2.4.2. Definition to be used

“Degree of Cleaning” - refers to the percentage of trash removed by a cleaning machine.

Degree of cleaning = Trash in input material – Trash in output material Trash in input material

X 100

“ Cleaning Efficiency” – Refers to the percentage of trash contained in the waste removed by a cleaning machine.Low fibre content in the waste gives a high cleaning efficiency

Cleaning efficiency = Total waste percentage – Fibre content percentageTotal waste percentage

X 100

2.4.3. Results from plant

Customer in Spain

A series of cleaning function tests were performed to demonstrate the full range of trash removal and theassociated fibre loss. The material used was relatively clean cotton with 1.7 % trash, 1 3/32” staple from a varietyof origins.

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Technology Handbook

2.4.3.1. Effect of cleaning settings

To find the optimal machine setting on the UNIclean, the entire range of the VarioSet field was evaluated. A significant difference in degree of cleaning and especially, the composition of the extracted waste was realized.

19.8 % cleaning degree 40.1%

87.4% trash in waste 61.5%

12.6% fibre in waste 38.5%

33.0%

79.8%20.2%

16.5% 38.3%

91.5% 67.6%

8.5% 32.4%

The final adjustment of the VarioSet was; Cleaning intensity = 0.6 Relative amount of waste = 4

This setup resulted in a very good cleaning efficiency, together with a superior fibre yield. The Customer realizeda 1.52 % increase of the fibre utilization, compared to the conventional blowroom environment.

2.4.3.2. Undesirable practices

Bad cleaning settings. VarioSet use not understood by customer. Stop/Go ratio of the UNIfloc too low.

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2.5. Bale Laydown and Fibre Feeding

2.5.2. General Information

Fibre feeding from the bales is extremely important. Quality control and process control starts with careful fibreselection for consistent fibre properties and the correct location of bales in the bale laydown.The removal of the fibres from the bales is the first step in the opening, cleaning, and mixing/blending of thematerials. Additionally, the feeding rate must meet spinning plant needs at every processing step. The fibrefeeding should not limit the plant’s production capacity.

2.5.3. Bale laydown for cotton

Spinning plants use cottons of various types and qualities from different regions throughout the world. It is veryimportant to arrange the bales to minimize “Quality Waves” created by fibre variations found between bales. HighVolume Instrument (HVI) testing is now widely used and can enable the spinner to better controlconsistency of the material in process.

Preferred guidelines: Lay down the maximum number of bales. Laydown bales for 24-hour production if space is available. Laydown bales on the first shift. Laydown bales when supervisor is available. Arrange bales in small groups (mini – laydown). The average fibre properties of each mini-laydown should

be the same as the overall blend average.

Problematic bales should be spaced apart and not placed at either end of the laydown. Bales should be opened and allowed to “Bloom” and condition for 24 hours if possible. At the run-out of the bales at one side, new bales should be moved into place and the remaining bale

ties removed as soon as possible.

The “Rest” of the fibre left from the previous laydown should be picked up and either, Be formed into a mixed bale and the placed in the middle of the next laydown, or

Be packed as pieces between the bales of the next laydown. Avoid placing the remaining layers of fibre on the top the bales of the next laydown.

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When manually levelling the tops of the bales, push the excess material between the bales. Warning! Grouping bales in the laydown by bale height, to avoid manual levelling, can lead to

concentrations of fibre properties. This creates quality waves that cannot be eliminated in the subsequentoperations and can cause “blow-ups” in spinning.

Remove most of the bale ties in a preparation area before moving the bales to the laydown position.Carefully remove the last ties and be sure to avoid metallic parts contaminating the fibre. Parts of bale tiesare a major cause of fire.

2.5.4. Bale laydown for man made fibres

The different fibre types, such as polyester, nylon, viscose /rayon, acrylic, polypropylene and several special

technical fibres are produced for specific applications and end uses. The length, denier, crimp, cross-section,strength /elongation and fibre finish are some of the properties normally controlled by the fibre producer.

Care should be taken to follow the producer’s bale laydown recommendations. For example, fibres formdifferent batches and lots should not be mixed for critical end products.

Warning! Some plants use low cost “un-branded” fibres for some applications. However, this can lead toproblems in high production spinning operations.

If the fibre finish does not have sufficient antistatic agent, the fibres will tend to tag and choke in thetransportation pipes, chutes and in the blowroom and carding equipment. Additionally laps will increase inthe drafting zones resulting in quality problems and a loss of machine efficiency.

If the fibre finish has insufficient lubrication, excessive wear can occur in all processing machines. This canlead to major problems in rotor spinning where opening rolls, rotors and nozzles can prematurely wear out.

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Technology Handbook

3. UNIfloc A 11

3.1. Overview of proceeding process

The control of the bale laydown directly affects the performance of the UNIfloc. The number of assortmentsdetermines the maximum production rate.

The positioning of bales should be performed to obtain consistent mixing and, ultimately, blending of the fibres. The waste bales and bales of unusual colour should be carefully located so as to avoid an undue influence on

the consistency of the blend. Wherever possible mix the bale location in the laydown.

Regions of origin should not be separated. Fibre properties should be averaged in mini-blends. The presence of sticky cotton quickly contaminates the equipment. Care should be taken to control the number of

sticky bales in the laydown.Fibre appearance can indicate troublesome cotton.

3.2. Principal features

The UNIfloc is a unique machine designed to remove small tufts of fibre from the top of bales in preparation foroptimal cleaning, mixing and blending. The principal features are:

Production up to 1400 kg/hr with the 2300 mmwide frame feeding from a single laydown.

Production up to 950 kg/hr with the 1700 mmwide frame.

Laydown length up to 50 m. Up to 130-bales/ laydown on each side A laydown “run-in run-out” program to

automatically compensate for variations in baledensity from top to bottom by adjusting “take offstep depth” to maintain a constant productionrate.

A laydown transition program automaticallyswivels the tower to remove fibres from the newbales during the run-out phase of the old bales(bottom 50 cm).

i.e. several cycles of - 8 passes on the oldbales and 2 passes from the new laydown

Minimum of 18 bales when feeding cotton or 12bales of man made fibres are required forsatisfactory mixing.

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3.3. Air requirements

Transport air from the UNIfloc: 0.85 – 1.20 m3/sec Suction in the pipe: 400 Pa (40 mm water)

3.3.2. Undesirable practices

Go/stop ratio - Too low. - Production rate and fibre quality affected Laying bale parts on top of the new laydown. - Creates chokes and loss of blend control. Incorrect location of waste bales. – Waste bales should not be concentrated in one area or located at the end

of the laydown. Inadequate bale blooming time and the variation in blooming time between bales.

Warning: Spiral pipes should not be used for fibre transportation because of excessive swirling and fibreentanglement. Where fibre passes through a fan, be sure that a “material-handling fan” is used.Where fibre is transported from one building to another it is necessary to insulate the pipes in cold climates, toprevent condensation in the pipes, which causes fibre chokes.

3.4. Start up suggestions

The production rate of the UNIfloc should meet the needs of the blowroom. It is very important to balance thedelivery rate with the needs of the rest of the line. The effective running time or GO / STOP ratio should be 85%to 90%.

A starting guideline is to use the basic default values and then adjust the settings to optimize the degree of fibreopening and the production rate.

There are four settings that can be adjusted:

3.4.1. Take – Off – Roll penetration

Controls tuft size.

For cotton bales normal settings are: 2 mm for low production rates with soft bales, 3 mm for low production rates with hard bales, 3 mm for high production rates with soft bales, and 4 mm for high production rates with hard bales.

For bales of man made fibres normal settings are 0 to 2 mm.

Illustration of Roll Penetration

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3.4.2. Arm lowering steps

Controls the production rate and is automatically varied during the run-in / run-out program which has to beprogrammed depending upon the variation of bale density.

A guide line of take off depths /production rates for the middleportion of cotton bales is:

1 mm for 200 to 350 Kg/hr 2 mm for 350 to 600 Kg/hr 3 mm for 600 to 900 Kg/hr 4 mm for 800 to 1200 Kg/hr 5 mm for 1000 to 1500 Kg/hr

Key:Level 1: very hardLevel 2: hardLevel 3: mediumLevel 4: softLevel 5: very soft

3.4.3. Arm traverse speed

The travelling speed of the arm affects the production speed. Care has to be taken to avoid overloading theopening rollers, which can cause unopened fibre to be fed resulting in chokes in the transportation system.Normal traverse speeds are between 9.5 and 11 m/min.

3.4.4. Take off roller speed

The take off roller speed can be adjusted to feed smaller tufts, but care has to be taken to ensure that neps are

not created or the tufts are not too small. When the tufts are too small the material is too bulky and is difficult totransport without choking in the pipes.

1500 rpm is normal for cotton1300 rpm is normal for man-made fibres

Suggested set up steps to increase the production rate for cotton.

Progressive production increase

Traverse speed 9.5 m/min 9.5 m/min 10.5 m/min 10.5 m/min 11 m/min 11 m/min

Roller speed 1600 1600 1600 1600 1600 1600

Roller penetration 3 mm 3 mm 3 mm 3 mm 3 mm 4 mm

Arm step depth 3 mm 4 mm 4 mm 5 mm 5 mm 5 mm

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Illustration of the variation in step depth during therun-in / run-out program



Technology Handbook

3.4.5. Gearing plan A11 UNIfloc

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3.5. Troubleshooting

3.5.1. Production rate too low

Check and adjust if necessary. Arm lowering step distance – too low Take-off roll protrusion - too low Traverse speed - too low. Run-in / run-out not optimized Excessive assortments or tower swings. Change of material, particularly bulky man made fibres such as acrylics.

3.5.2. Chokes in the fibre transport line

Remove loose fibre from the tops of the laydown and pack it between the bales. Check the air speed in the different points in the line. Check the condition of pipes. Seams, joints, surfaces and bends can cause fibre chokes. Check the condition of the fan inside the UNIfloc. All material, including trash, pass through this fan. Ensure correct fan speeds. Reduce the penetration of the take-off roll. If chokes occur after the fibre has passed from one building to another, check to see if condensation

is occurring in the pipes between the buildings. Insulation may be necessary in cold climates.

3.5.3. Excessive neps in the opened material

Check the airflow from the UNIfloc. Insufficient airflow can cause an increase in the nep level. Check nep levels throughout the system to determine where the change in nep level occurs. Throughout the laydown and look for problematic bales, Take several samples immediately after the UNIfloc, Take several samples at the entry to the machine following the UNIfloc. Check the condition of the teeth on the take-off roll. If damaged they should be replaced. If worn or rounded

they should be replaced or sharpened if the replacement parts are not available. Reduce the take-off roll speed.

3.5.4. Trash in the opened material is too high

Check the go/stop ratio and correct if not close to 85%. Increase take-off roll speed to reduce tuft size.* Reduce the penetration of the take-off roll to reduce tuft size.* Reduce traverse speed.Note: Some of the above actions may reduce the production rate. Production rate of the UNIfloc should bechecked for several shifts. One check is not enough.

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Technology Handbook

4. UNIclean B 11

4.4. General Information

The UNIclean is an outgrowth of Rieter’s experience in removing trash from cotton while it is airborne as the firstcleaning point in the blowroom and is consistent with the cleaning philosophy:

a minimum number of cleaning positions maximum working efficiency optimum fibre preservation

high raw material yield

Removal of foreign matter during the first cleaning stage in the blowroom.

UNIclean B 11

4.5. Principal Features

Production up to 1'200 kg/h (2'600 lbs/hr) Selective trash removal High dedusting effect Gentle fibre treatment VarioSet for easy operation Change waste amount in a range of 1:10

4.6. Mode of operation

In contrast to conventional pre-cleaners, i.e. single-cylinder cleaners or horizontal cleaners, material transportinside the UNIclean takes place mechanically by means of special pins, independently of the conveying air. Theraw material is forced over the cleaning grid bars where trash is removed and an integrated de-dusting unit toremove fine particles.The waste is collected inside the machine and is automatically released to the waste suction system.Since dust and sand cause considerable problems in the spinning operations, the UNIclean has been equippedwith an integrated dedusting unit. Dust, sand, some pepper trash and fibre fragments are separated from thecotton by a perforated plate and released to the filter system. Only some 0.5 cubic m/s of dust laden exhaust airhas to be removed in the dedusting function.

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H. Schwippl 17.11.06 20/25

Exhaust air (dust)

Waste air

1

2

3

1

2

3

1

2

3

Material feed

Waste extractionroller

Material outlet Pin roller

Grid bars with electro cylinder control

To control the cleaning action of the UNIclean both the “cleaning intensity” and the “waste rate” have to beprogrammed into the machine. The cleaning intensity controls both the speed of the drum and a compensatorysetting of the grid bars. Increasing the “cleaning intensity” increases the trash removal. The “waste rate” changesthe grid angle to remove more or less material. These setting are made on the machine control panel or in theVarioSet program if it is available.

4.6.1. Fibre transportation

The material is blown to the UNIclean, and is circulated seven times inside the machine by the hooks on thedrum. The cleaned fibre is sucked from the machine by the transportation fan. Careful adjustment of the airflow isessential to the effective operation of the machine.Part of the feed transport air is sucked through the perforated plate by the dust waste fan. Fine particles areremoved and discharged to the filter system.The quantity of air required to transport the fibre to the next machine exceeds that amount passing through themachine.To minimize the volume of air passing through the machine, a supplementary air inlet is provided to allow extraair to be sucked into the system as needed.

4.6.2. Cleaning process

As the fibres enter the machine they are carried in a circular motion by the tines.The fibres are directed by the guide plates to make seven revolutions before leaving the machine. In eachrevolution the fibres pass the grid bars and the perforated plate.The “Cleaning Intensity” can be adjusted step-less, to changing the rotational speed of the drum. The adjustmentcan be done while the machine is running. Additionally, the angle of the grid bars is automatically changed incombination with the speed.The “Waste rate” can be varied by changing the grid bar angle with an electrically controlled cylinder.The settings of the cleaning intensity and waste rate can be recalled and used again at a later date.



Technology Handbook

4.6.2.1. Cleaning intensity

Production Setting Drum speed0.0 (low) 480 rpm

Step-less adjustment toUp to 1'200 kg/h

1.0 (high) 960 rpm

4.6.2.2. Relative waste rate

Setting «1» (Low): Setting «10» (High):

Grid closed, lowest waste rate Grid open, highest waste ratedark waste composition light-colored waste composition

4.6.2.3. Cleaning characteristic diagram

The typical amount of waste to be removed byvarying the settings is shown in the following chart.The influence of the cleaning intensity settingincreases as the waste rate is increased.

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As a guideline, the following table gives values of the cleaning intensity and the waste rate according to the trashcontent of the cotton to be cleaned.

Trash in cotton Applications Cleaning intensity Waste rate

0.5 to 2,0 % Clean cotton finecombed yarns

0.5 to 0.9 0.5 – 0.8 %

1.0 to 3.5% Ring spun cardedyarns

0.6 to 0.9 0.8 – 1.5 %

1.5 to 4.5% Rotor yarnsNe 10/1 to 24/1

0.7 to 0.9 1.0 – 2.0 %

3.0 to 6.0% andmore

Rotor yarnscoarse counts

0.2 to 0.7 1.5 – 4.0 %

4.6.3. Waste disposal

The waste is removed periodically through the airlock roller. The interval is determined by the waste transportsystem.The waste extraction roll incorporates an airlock with seals in waste chamber to prevent excessive good fibrebeing pulled out with the waste.

4.7. Determining the amount of waste

To determine the amount of waste extracted, the waste has to be removed by hand, weighed and compared withthe production rate to calculate waste %.

Follow the instructions on how to isolate the trash chamber from the suction system and manually operate the airlock roller to remove the trashTake at least three (3) tests, each of at least half an hour.(For a provisional test, collect the waste for more than one complete cycle of the UNIfloc.)Record the running time of each test.

Calculate the production (kg) during the test time = Carding production rate from the line kg/h x test time in min60

Waste % = Amount of waste removed x 100Production during test + waste

Note:The system should be operating with an acceptable stop/go ratio otherwise when the system is optimized theactual waste % will vary from the tested value.Stop/go ratio = Running time of the UNIfloc (operating hours counter)

Actual time

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4.8. Trouble shooting

4.8.1. Neps too high in the material downstream

Neps can be created at many points. Carefully check the nep levels throughout the system. Immediately after the UNIfloc. At the entry to the UNIclean. At the exit of the UNIclean At the entry to the UNImix.

Check and correct the volume and speed of the airflow in the system. Check the condition of the fans

Frequently a nep increase occurs in the transportation pipes because of, Rough pipe surfaces, Tagging and roping, Rolling of stock, Bad joints

4.8.2. Trash too high after the UNIclean

First check the cleaning effectiveness of the UNIclean. Normal levels depend upon the type of cotton and theamount of trash in the cotton.

Check and correct the stop/go ratio of the UNIfloc. If it is too low than the instantaneous fibre flow ratethrough the UNIclean will be too high.

Adjust the cleaning settings of the UNIclean. Check to see if there is trash being pulled back from the waste chamber through the grid bars and into the

cotton. If so correct, 1) the airflow through the UNIclean or, 2) the trash extraction system. Check the bale laydown to see if there is a grouping of bales with a high level of trash or waste. This produces

surges of material with high trash content that can appear to be a problem with the UNIclean. Distribute thebales throughout the laydown.

4.8.3. Blockages in the system

Incorrect airflow in the system – check air speed and volume. A backpressure from the UNImix can occur if it is too full. Check the air pressure switch on the UNImix. Check the condition of the fibre transport fans, they could be loaded, damaged or not running at the

correct speed. Be sure that the fan belts are in good order and tight. The air opening for the supplementary air may not be set correctly and allowing excessive false air into

the pipes. The pipes may be damaged or contaminated causing the fibres to stick and choke. Long transportation distances

and/or multiple pipe bends are problematic. Check the stop/go ratio of the UNIfloc. If it is too low, than the actual material flow rate can overload the system

and cause chokes. It is important to maintain a ratio of 85 to 90%

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Check the performance and settings of the UNIfloc to be sure that it is not over feeding un-opened, largepieces,

of cotton from soft bales or bale tops.

4.8.4. Waste not being removed from the trash chamber

The waste extraction roll does not turn, the drive system may be jammed, The control from the filter system may be out of order, The filter may be overloaded and a back pressure built up, Waste exhaust fan may not be operating correctly. Note: If a damaged waste extraction roll has to be replaced, the plant can continue to operate

without using waste extraction roll with continuous waste removal system. It is necessary to closethe grid bars to prevent excessive fibre being pulled out along with the waste. This is only atemporary measure.

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5. UNImix B 70

To be added later.

6. UNIflex B 60

To be added later.

7. UNIblend A 80

To be added later.

8. UNIstore A 77

To be added later.

9. Minimix B 3/3

To be added later.

10. Mixopener B 3/4

To be added later.

11. Wasteopener B 2/5

To be added later.

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Technology Handbook

3.4. Flats 293.4.4. Direction of flats movement 29

3.5. Doffer 293.6. Cylinder plates and tongue 303.7. Hook formation 303.8. Sliver formation 313.8.4. Sliver coiling 323.9. Autolevelling 323.10. IGS-classic 33 3.11. IGS top 353.12. Flat setting 35 3.13. Trash removal and classification 363.13.4. Effect of overall system cleaning 36

4. RECOMMENDATIONS 37

4.1. Process recommendations 374.1.4. Matt weight and condition 374.1.5. Feed plate setting 384.1.6. Licker-in and cylinder speeds ranges by fibre types 384.1.7. Basic settings around the cylinder 394.1.8. Doffer 404.1.9. Delivery section 414.1.10. Carding synthetic fibres 414.1.10.1. Fibre crimp 424.1.10.2. Speeds and settings on the card 424.2. Air requirements 434.2.1. Air pressure 434.2.2. Exhaust air / Suction 434.2.3. Room conditions 43

5. TROUBLESHOOTING 45

5.2. Impact of machine settings 455.1.1. Feed roller to licker-in 455.1.2. Feed trough (plate) nipping distance (D) 455.1.3. Licker-in to cylinder 455.1.4. Flats to cylinder 455.1.5. Cylinder to doffer 465.1.6. Tongue to cylinder and doffer 465.2. Reasons for sliver breaks 465.2.1. Trash accumulations at the condenser 465.2.2. Irregular fibre transfer between doffer and stepped rollers 465.2.3. Bad doffer condition 465.3. Neps in the sliver are too high (Corrective actions) 475.3.1. Material being fed to the card 475.3.2. Consider the card room! 475.3.3. Suggested procedures and corrective actions 475.4. Trash in the sliver is too high 48

5.4.1. Suggested procedures and corrective actions 485.5. Short fibre content of the sliver is too high 49

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5.5.1. Suggested procedures and corrective actions 49



Technology Handbook

5.6. Improving the sliver uniformity 495.6.1. Suggested procedures and corrective actions 50

5.7. Impact of preceding processes 515.7.1. Bale laydown 515.7.2. Opening and cleaning 515.7.3. Fibre transportation 525.8. Interpretation of spectrogram information 52

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Technology Handbook


1.1. Introduction

The carding operation is the most important phase of short staple spinning. “Well carded is half spun” is an oldexpression that applies equally today. In the modern carding process there are three basic functions that have tobe considered, namely: lap formation using the chute feeding system, the carding steps to produce a sliver and the control systems to facilitate the production of high quality sliver at increased production rates.

1.1.1. Carding functions

The chute should supply a matt to the card which is uniform in mass and consistent in fibre openness, the card opens the fibre tufts into individual fibres, removes a high proportion of the neps, in the case of cotton, removes a majority of the trash, blends fibres in the short term, initiates fibre orientation, produces a continuous sliver of controlled mass.

Needless to say, for the card to perform well it must be provided with well opened, well cleaned and adequatelymixed/ blended material.

Cards that are set and operated correctly are the most effective machines in the line for removing trash and neps,but it is erroneous to leave all of the work to the card.

The blowroom should function to: mix and open the fibres, remove an optimal amount of trash, minimize nep formation minimize fibre damage. minimize the loss of good fibre in the waste.

A goal of the blowroom is to: remove 70 to 75% of the trash in the bales, not increase the nep level by more than 100%, not increase the short fibre content (SFC). not reduce the staple length of the fibre.

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Technology Handbook


1.2.1. Current carding machines

The C 60 and C 60-H Cards represent the current line of Rieter’s carding concepts. With this revolutionary newcarding technology of wider and smaller diameter cylinder, in conjunction with single or triple Licker-In andvarious sliver delivery concepts, the current models have evolved and proven themselves in recent years.

The C 51 and the C 51 Hi•Per•Cards represent the older line of carding technology that had evolved throughmany models.

C 51 Card C 60 Card

Chute and card form a single unit:

The production features of the integrated chute system are:The chute system is designed for cotton, man-made fibres and blends up to 65 mm (2.5″). Matt weight - of Cotton from 500 to 1’100 g/m.

- of Man made fibres from 400 to 900 g/m.

Production up to 220 kg/hr (= C 60H, 120 kg/hr = C 60) Preliminary opening is gentle on the fibers, thus ensuring optimum batt feed.

The features of the older A70 chute were:

The aerofeed A 70 chute for cotton, man-made fibres and blends up to 65 mm (2.5″). Matt weight - of Cotton from 400 to 800 g/m.

- of Man made fibres from 300 to 700 g/m. A 70 Chute production rate up to 120 kg/h Double chambers with fibre opener feeding the lower chute chamber to produce a controlled matt with

feeding functions integrated with the carding requirements.

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Technology Handbook

1.2.2. Aerofeed system

In the Rieter blowroom one or two fine opener / cleaners open the fibres and feed them into the distributionsystem.The fibres pass through the fan and are blown into the transportation ducts that pass over the tops of the chutes.The top chamber of the chute has a perforated side sheet though which the transporting air flows. All of the transportation air has to pass through the perforated sheets, and depending upon the degree of chutefilling the fibre passes to the chute with the least resistance to air flow.

When all top chambers of the chutes are full, there is reduced airflow and the over-pressure increases in thefeeding ducts. A pressure sensitive switch, between the fan and the first chute detects the pressure increase andstops the feeding machine.

Similarly, when the air pressure drops to a pre-set low level the feeding machine is again started.

1.2.2.1. Function of the integrated Chute

The chute is integrated into the card and thus is a vital component of the card for ensuring optimal overalloperation of the card.Compared to the A 70 chute, the chute of the C 60 has an opening unit with a feed plate and feed roller.

The chute is part of the aerofeed pneumatic card feeding system. It can be used in a linear arrangement or in the“U” form.

Feed plateFeed roll

Removal kniveOpening roller

A cross-sectional view of a typical chute is shown in theillustration.

The fan blows the fibres through the fibre duct (1). Gravityand the airflow cause the fibres to fill the upper feedchamber (2).

The transport air passes through the perforated sheet into

the extraction air duct.

As fibre is fed to the lower chute, the perforated sheet isexposed allowing more air to flow bringing additional fibre tothe upper chute.

The upper feeding chamber is equipped with a single feedroller (3), a feeding plate with a defined nipping point tocontrol the fibre flow to the opening roller (4), which opensthe material into tufts and transport the lower chute (5).

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Technology Handbook

Fibre batt compression in the chute:The standard version has a closed air circulation system, which ispowered by a fan.The integrated fan controlles the air flow and effects even fibrecompression across the width.

A set of light scanning sensors monitors the material level in the lower chute and regulates the speed of the upperfeed roller to maintain a controlled level and batt mass.

The batt weight is primarily governed with the lower light sensor, which is in control during normal productionspeed. The upper light scanner keeps the filling level slightly higher during the “creep speed” operation of the C60 card.

By adjusting the positions of the chute walls inward or out, the batt weight and volumne can be influenced.

The batt is taken from the bottom of the lower chute by the feed rollers (6) and fed to the card.

1.2.3. Features of the C 60 Card

Carding production rate is up to 220kg/h with the C 60 H Card are possible, depending upon the type of fibresbeing processed, the sliver weight and the end uses.

A short selection of some elements of the C60 carding system is shown in the following.

1.2.3.1. Unidirectional feeding to Licker-In

The card C 60 is fitted with state-of-the-art unidirectional feed. The distance between nipping point and combingpoint ( 1st roller of the of the triple Licker-In unit, or on single Licker-In) can be adapted to the staple. Thisconserves the natural properties of the fiber.This gentle material opening helps to counteract any fiber damage.

The new design of feed trough (2) is slightlyflexible at the tip. This prevents the levellingbeing affected by any variations occurring in thebatt density over the width.

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Technology Handbook

1.2.3.2. Licker-in options: Triple / Single roll unit

The triple licker-in unit is recommended for highest performance and for cotton with high trash content. Thematerial tufts are opened even more, and coarse trash and dust is extracted.

At the cotton and the swing version, the first and third rollerhave a directly suctioned trash mote knife assigned to them.If the card is specified for man-made fibers the trash moteknife at the 3rd licker-in are substituted by an aluminumprofile.

The single licker-in opens the material tufts even more withabsolutely minimum loss of sound fibers, and extracts gentlycoarse trash and dust.

The licker-in has a suctioned trash mote knife assigned to it.

With the effective opening in the chute, the card C 60 with single licker-in has a much better opening thanprevious modles A 70 / C 51.

The modular construction allows rapid maintenance since the unit can be dismantled as a whole and replacedimmediately by a unit prepared in the shop.

1.2.3.3. Speed ratio cylinder / licker-in

The cylinder has a diameter of 814 mm. The carding speed ( circumferential speed of cylinder ) is basically thesame as with conventional cards. Therefore the rotational speed is accordingly higher by the C 60.

The load remains unchanged as regards the fibers. What has altered is the about 60% higher centrifugal forcewhich is used to extract trash.

Rieter's technological concept also includes the material-optimized speed ratio between licker-in and cylinder. Adapted according to the trash content in the raw material, the licker-in speed can be increased in order toachieve the maximum trash extraction level.

1.2.3.4. Cylinder drive

Depending on the material feed, the speed of the cylinder can be set to a range of between 600 and 900 rpm foroptimum carding.

Standard is the version with a frequency converter.The frequency inverter allows a speed between 600 and 900

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Technology Handbook

1.2.3.5. Multi-range card clothings

Multi-range clothings have an enormous number of possible applications in six clearly defined areas,guaranteeing the customer maximum flexibility. The six defined ranges of application are:

• Rotor ≤ Ne 30

• Rotor / Ring carded

• Ring combed ≤ Ne 60

• Ring combed

• Synthetics (MMF) ≤ Ne 90

• Blends cotton/MMF ≤ Ne 90

• Sawtooth flats.

1.2.3.6. Flat movement

The flats move in the opposite direction to the directional rotation of the cylinder. This way, the coarsest trash isremoved immediately, as the flats enter the working range / carding zone.

The flats are atatched to a belt and thue moved in acircular motion. The flat segments can be changed veryquickly as each flat unit is simply pushed onto theclamping nubs of the flat belts and secured with a holderclips.

The flats are driven with a belt and pully drive, directlyfrom the cylinder shaft.

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Technology Handbook

1.2.4. Features of the C 51 Card and C 51 Hi•Per•Card.

Carding production rate is up to 120kg/h with the Hi•Per•Card option depending upon the type of fibres beingprocessed, the sliver weight and the end uses.

The following diagram shows some the elements of the card: Primary features include.

Modular licker-inunidirectional feed 1.2.4.1. Unidirectional feed and licker-in

Unidirectional feed to minimize fibre damage at the licker-in,

Adjustable nipping distance for short staple fibre, Matt feed trough controls the fibres. Any change of matt

thickness is detected as a movement of the trough and thelevelling system responds by changing the card draft.

Modular licker- in section for all applications, High performance trash separating knives and carding

segments under the licker-in.

Flats with ground down heel1.2.4.2. Cylinder wire and flats

Cylinder clothed with high performance wiredepending upon fibres and applications.

Improved setting and carding action using revolving flatswith ground down heel,

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Technology Handbook

1.2.4.3. TREX and TREXplus

TREX and TREXplus with stationary carding plates on thecylinder in positions before and after the flats cardingzone.

Improved suction and flats cleaning,

“Cleanmaster” fixed flats system as an option insteadof revolving flats. Currently used only for man-made fibres.

1.2.4.4. IGS-Classic on C 60 and C 51

(IGS – classic) programmable system to automatically sharpen the cylinder wire during production.Maintaining sharp wire extends the lifetime of the wire and maintains an effective nep removal performance.

1.2.4.5. IGS-Top on C 60 and C 51

(IGS – top) automatic system to periodicallysharpen the flats during production to minimize thedeterioration of the carding action due to dull flats,

Improved consistency of carding quality with theuse ofIGS – classic and IGS – top,

No machine down time or loss of production due togrinding the card clothing. (The flats have to beperiodically reset to the cylinder to maintaincarding performance)

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TREXplus for Hi•Per•Card

IGS -classic Automatically maintains the sharpness of the cylinder wire with up to 400 cycles.

400 x

3........4 x

400 x

3........4 x

Automatically maintains the sharpness of the Flats.



Technology Handbook

1.2.4.6. Automatic waste removal

Separation of the licker-in waste from the flats and fly waste in an automatic waste removal system tomaximize the value of the waste.

1.2.4.7. Autolevelling

Autolevelling of the sliver weight using both open loop and closed loop techniques.

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Technology Handbook

2. Technological Functions

The complex functions of the card will be described in detail in the following sections.

2.1. Opening the fibre tufts

Opening the fibre tufts into their individual fibres is the primary purpose of the card. As a result of the actions ofthe ginning process, the cleaning steps in the blowroom and the fans used to transport fibres between machines,entangled and knotted fibre bundles are created. These bundles are frequently referred to as – horseshoes,starfish, buttons, slubs and neps.

If these bundles are not eliminated, the spinning process will be limited to coarse counts and the yarn quality willbe low.

2.2. Neps reduction

A distinction is made between two basic types of neps: Fibre neps: small knots of entangled fibres, often with immature fibres at their core Husk or seed coat neps: consist of tangled fibres attached to a fragment of seed coat.

In general, cotton neps are associated with fine fibres, but in particular with immature low micronaire cotton.

The susceptibility to neps is typically:With micronaire 5.0 - 1With micronaire 4.5 - 5With micronaire 2.5 - 40.

Investigations of causes of neps in general showed that:60% due to immature fibres,35% due to normal fibres,5% due to seed coat fragments.

However it should be pointed out that certain cotton varieties and growing regions produce a cotton seed that hasa relatively fragile coat. The coat breaks off with the cotton fibre during the ginning operation.

Owing to the design of blowroom machinery and the nature of fibres, the nep count progressively increases up tothe card and is then reduced considerably. During the rest of the preparation processes the nep count increasesslightly with the exception of the combing process in which again the neps are removed.

It is normal for the nep count in the card matt to be double the count in the raw cotton. The card nep removal ratecan be between 80 and 90 percent of the neps in the matt, i.e.

Very good / medium / low grade cotton Manual count AFIS - VFM

Neps in raw cotton 10 / 30 / 50 per 100 mgNeps in card matt - 15 / 40 / 80 per 100 mg

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Neps in card sliver 4 / 9 / 16 per 100 mg



Technology Handbook

A decisive factor is not only the number of neps but also the size. Small neps are often not visible in rotor yarn orin coarse ring yarns, but are of major concern in fine-combed yarns. Small neps are difficult to remove even by

the comber.Neps may be reduced in two ways: by removing them or by opening them. It has demonstrated that 75% of allneps can be opened, but normally it is no more than 60%.The majority of the unopened neps either passes into the sliver or is removed by the flats. A small percentage isremoved in the waste.

Opening / removing of neps at the card is primarily accomplished by: Close settings of the clothing, Sharp clothing Low doffer speeds Light sliver weight

Increasing production rate increases the nep level in the sliver.Reducing production rate reduces the nep level.

Every plant should establish upper tolerable nep levels. When these levels are approached the cylinder and flatsshould be re-ground.

- All points on the cylinder should be sharpened,- 90% of the flat points should be touched up.

The frequency between grindings is dependent upon the amount of material processed, the abrasive nature ofthe fibre dust or finish and the requirements of the end product.

2.3. Separating short fibres by using flats

The mean staple length of the fibres in the flat strips is much shorter than that of the delivered card sliver. Thatthere are many more short fibres in the flat strips is explained by the fact that the cylinder easily holds the longerfibres that pass into the sliver. The short fibres tend to float into the flats and some become pressed into theclothing and are ultimately stripped. This can possibly be seen as performing a valuable function of the card, i.e.eliminating short fibres. This is only partially correct: Flat strips can be in the range of 1 to 2% of the fibre processed. Approximately 50% of the fibres in the flats are short fibres,

The short fibre removed by the flats is 0.5 to 1.0% of the total fibre processed. The carding action breaks some fibres and creates short fibres that amount to as much if not more than the

flats remove. Driving the flats at a higher speed can increase the amount of flat strips. While this increases the quantity of

the flat strips, considerably more good fibres are removed. Each spinning plant has to determine the value ofincreasing the rate of flat strip removal.

NOTE: The primary functions of the flats are to remove and open up neps plus eliminate foreign matter.

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Technology Handbook

2.4. Separating short fibre by suction

High pressure points are generated by the various rotating surfaces. When these pressure zones are released byapplying a slight suction there is a tendency for the dust and short fibres to be withdrawn.Suction channels are located throughout the card, some primarily for dust / air control and others to perform acleaning function.

Suction over the licker-in and at the licker-in / cylinder transfer zone remove dust and fly, Suction at the TREX and TREXplus is applied to remove trash and short fibres. The design, incorporating

the fibre-guiding segment, minimizes the loss of good fibre while allowing the trash and very short fibre to beextracted.

Suction inside the flats encourages the collection of dust and fly released at the cylinder / flats pressurezone.

At the cylinder / doffer zone a suction duct is provided to extract short fibres, fibre fragments and dust.

The suction levels have to be correctly controlled to enable the devices such as the TREX and TREXplus toperform their functions.

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Technology Handbook

3. Machine elements

3.1. Card clothing

Card wires are manufacturaed with a variety of rib-base designs depending on the application and machineconcept. Some of the designs include surface wound, camlock and groove installation.

A brief overview of the wire design features, which have a profound influence in the success or failure of cardingdelicate fibres, at high surface speeds with a minimum of fibre damage.

Some of the technical descriptions and wire angles are as follows:

1 = Shoulder thickness2 = Front Angle3 = Total height4 = Pitch5 = Height of tooth6 = Web height

1. The sholder thickness is the width of the rib or camlock and determans the distance from tooth-row totooth-row. This influences the number of points per square inch and contributes to the strength of thesurface area.

2. The front angle is the fibre-carding angle, which is the main influence factor in the aggressiveness of thecarding action. This angle limits the number of teeth per linear inch and placed demands on the cylinderspeed. In addition, it determans the fiber holding capacity of the wire.

3. The total height of the wire contributes to the amount of fibres carried by the wire. It also contributes to

the outer diameter of the clothed carding element.

4. The pitch is the distance from the tip of one tooth to the next. This determains the number of linear teethper inch, the smaller the pitch the more teeth per linear distance.

5. The height of the cut tooth defines the capacity of the maximum fibers carried. On the cylinderapplication, the tooth height defines also the remaining web and fiber crossblending factor within thecard.

6. The web height is the amount of the tooth left above the rib, which is not puched out. Trash particals canbuild up in this space, but air currents can also aid in the lift of fibers from the cylinder.

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Technology Handbook

• The back angle will affect the tooth strength. It will aid or hinder the release of the fibres from the wire.

• The included angle is the result between the front and back angle and is the measurement of the tooth

shape. The sum of the front, back and included angles is always 90 degrees.• The tooth side angle is the tilt from the tooth-point to the shoulder and defines the strength of the tooth.

This wedge can aid or reduce the amount of trash build-up; cotton plant particles tend to be speared.

• Point thickness. The sharper the point, the better the separation of fibres, but the easier it can bedamaged. The wire must be rolled, punched, hardened and wound onto a reel without being damaged.

• The radius contributes to the release of the fibres and the life of the wire.

Blade width

T o o t h d

e p t h

T o t a l h e i g h t

R i b

h e i g h t

B l a

d e

h e i

g h t

Rib

Blade width

T o o t h d

e p t h

T o t a l h e i g h t

R i b

h e i g h t

B l a

d e

h e i

g h t

Rib

Pitch

Back angleRadius

Included

angle

Pitch

Back angleRadius

Included

angle

Front angleFront angle

Additional details about tooth shapes and side grinding is available from the technical department or the clothingsuppliers.

When the card is to be used for a range of different fibres types, the clothing has to be selected as a compromiseor combination, which will perform satisfactorily on each fibre type.

3.1.1. Card clothing for Microfibres

Microfibres are define as fibres with a fineness of < 1.0 dtex.Compared to fibres with conventional fineness, the production rates must be significantly reduced, for the reasonthat high fibre to fibre friction can cause extreme carding forces. Consequently the optimal card wires must bechosen when processing Microfibres.

With regard to the wire for fibre opening on the C 51 Card, the needle rollers have proven over the years, to bevery effective in relation to quality and quality consistancy. For the following trial range, a needle roller with 36points / 2 inch and a needle angle of 58 deg. was used as licker-in.

To keep the carding force as low as possible, a typical cylinder wire as used today, of 640 points and 30 degreesfront angle was applied for the Microfibres.

At the beginning of Microfibre processing in the 90’s, much finer cylinder wires were selected, such as 1080points per sq. inch. Over time, however, it became evident that in practice real disadvantages often resulted.Efforts to realize the highest possible quality with higher number of points, or to keep the number of fibres in thetooth gaps constant, as to the coarser fibres, resulted in excessive carding forces. The fibres could reach the

tooth gaps only with difficulties, due to high fibre to metal friction. This caused the carding forces to increasemassivly without achieveing an optimal carding.

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Technology Handbook

On the other hand, a wire that is too coarse, tends to overload the wire. This is due to a higher number of fibresbetween the teeth and in extreme cases, the fibres can no longer be delivered from the cylinder wire. Especially

with the low single-fibre mass of Microfibres, the centrifugal force on the cylinder is no longer sufficient to lift offthe fibre, as the centrifugal force is reduced linear to the fibre mass.

Therefore, with fibre counts of 0.9 dtex, a cylinder wire between 640 and 720 points per sq. inch and 25 - 30degrees front angle have proven to be successful in achieving the highest quality values. The optimal wiredepends also on the fibre characteristics, the fibre finish applied and the climatic conditions.

With this raw material, the 640 point wire showed, that the fibres do not allow an optimal delivery from the cylinderto the doffer. It was observed, that the relativly fine fibres became trapped in the wire grooves. An increase ofcylinder speed to achieve higher centrifugal forces was not chosen, for reasons of lowest possible fibre stress.

Consequently, the number of points on the cylinder, under otherwise equal conditions, was increased to 720

points per sq. inch. The running characteristics and the web quality were subsequently described as very good.

The card clothing is supplied in sets depending upon the applications. The following tables l ist some of thecharacteristics of typical card clothing.

3.1.2. Clothing C51 Technical data

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C51 Card Clothing (Points / sq. inch - Front angle)

Fibres

Very fine Yarn

combed Ring

Med-Fine Yarn

combed Nm 100

Coarse Yarn

Carded / OE

Man Made

> 1.0 dtex – 3.3

Man Made

< 1.0 dtex – 0.6

Yarn count> Nm 80

( >Ne 48 )Nm 40 …. 100( Ne 24 …. 60 )

< Nm 35( < Ne 20 )

Production 50 kg/h > 70 kg/h

Licker-in- points 41 41 - 61 41 - 61 32 36 pin roller

- angle 10 deg. 10 deg. 10 to 15 deg. 0 to 5 deg. 58 deg.

- rpm 900 - 1300 1000 - 1450 1300 - 1700 800 – 1100 1430

Example Graf VE-5010V- -8 Graf VE-5010V- -8 Graf VE-5010V- -8 Graf VD-5005V- -8 ?

Cylinder

- points 800 - 1080 800 to 1000 600 - 865 450 to 650 720- angle 30 deg. 40 deg. 30 deg. 30 deg. 30 deg.

- rpm 350 - 450 400 - 500 450- 600 400 - 450 400 - 450

ExampleGraf P-2030 x 0.4

CS Graf P-2040S x 0.4

CS Graf R-2030 x 0.5 Graf R-2530 x 0.6 CS Graf R-2530 x 0.6

CS

Flatclothing 550 480 410 350 430

Example Graf RSTO F55/0 Graf RSTO M48/0 Graf RSTO C41/0 Graf ILXT M35/0 Graf PT 43/0

Doffer- points 340 - 365 340 - 365 280 - 340 280 - 340 340 - 365

- angle 30 deg. 30 deg. 30 deg. 30 deg. 30 deg.

Example Graf N-4030B x 0.9 Graf N-4030B x 0.9 Graf L-4030B x 1.0 Graf L-4030B x 1.0 Graf M-5030 x 0.9



Technology Handbook

3.1.3. Clothing C60 Technical data

C60 Card Clothing (Points / sq. inch - Front angle)

FibresVery fine Yarncombed Ring

Med-Fine Yarncombed Nm 100

Coarse YarnCarded / OE

Man Made> 1.0 dtex – 3.3

Man Made< 1.0 dtex – 0.6

Yarn count> Nm 80

( >Ne 48 )Nm 40 …. 100( Ne 24 …. 60 )

< Nm 35( < Ne 20 )

Production 50 kg/h > 70 kg/h

Licker-in- points 41 41 - 61 41 - 61 32 41

- angle 10 deg. 10 deg. 10 to 15 deg. 0 to 5 deg. 0 to 5 deg.

- rpm 1000 - 1350 1200 - 1600 1400 - 1800 ? 1430

Example Graf VE-5010V- -8 Graf VE-5010V- -8 Graf VE-5010V- -8 Graf VD-5005V- -8 Graf VE-5005V- -8 Cylinder- points 800 - 1080 965 to 1080 600 - 865 450 to 650 720


- rpm 750 - 850 800 - 850 850 - 900 600 - 750 600 - 700

ExampleGraf P-2030 x 0.4

CS Graf R1535 x 0.4 Graf R-2030 x 0.5 Graf R-2520 x 0.7 Graf P-2025 x 0.5

Flatclothing 550 550 410 350 430

Example Graf RSTO F55/0 Graf RSTO F55/0 Graf RSTO C41/0 Graf ILXT M35/0 Graf PT 43/0

Doffer- points 340 - 365 340 - 365 280 - 340 280 - 340 340 - 365


Example Graf N-4030B x 0.9 Graf M-5030 x 0.9 Graf L-4030B x 1.0 Graf L-4030B x 1.0 Graf M-5030 x 0.9

3.1.4. Clothing sets

The clothing, with its wide scope of use is divided into five spheres of applications. Carded rotor yarns,

Carded ring yarns and combed rotor yarns, Combed ring-spun yarns, Man-made fibres of 1 to 2 dtex Blends of cotton and MMF of 1 to 2 dtex. (Also as combination or swing cards)

Suitable clothing wires have been developed for the Rieter cards in conjunction with the clothing suppliers ECC,Graf and Hollingsworth of Germany.

The specifications of the kits are reviewed periodically and upgraded when necessary. The exact details areissued with the machine specifications and can be checked by contacting the service or technical department.

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Technology Handbook

3.1.4.1. Wire recommendation C51

Effective January 1 2005, the following specification sheets are approved by Rieter Machine Works, ECC andGraf as wide-range clothing sets for our C51 and C51 Hi-Per-Card.

The strategy of the sales and service departments concerning the wire sets is as follows.• Definition Set contains specifications for: Cylinder (C), Flat (F), Doffer (D)

Card C 51 – ECC wire, Specification Sheet for „Wide-Range“ Clothings

Set A B C (F) C (EF) D (F) E

OE-yarn

coarse

OE- yarn fine

Ring yarn

Ring yarn

fine

Ring yarn

extra fine

Manmade

fibers

Blends /

Swing

Application

< Nm 35(< Ne 20)

Nm 25 ..... 50(Ne 15 .... 30)

Nm 40 .... 100(Ne 24 .... 60)

> Nm 80(> Ne 48)

1 - 2Dtex 1 - 2Dtex

Cylinder 5095D 5095D 5695D 5695D 666D 686D

Doffer 7300R2 7300R2 7300R2 7300R2 7300R2 7300R2

Flats Alpha 35Gradutecc

Alpha 45Gradutecc

Alpha 55Gradutecc

Alpha 55Gradutecc

Alpha 35Gradutecc

Alpha 45Gradutecc

C 51 ‚Hi·Per·Card‘ – ECC wire, Specifications for Productions > 70 kg / h

Set AH BH CH (F) DH EH

OE-yarncoarse

OE- yarn fineRin arn coarse

Ring yarnfine

Ring yarnextra fine

Manmade fibers Application

< Nm 35

(< Ne 20)

Nm 25 ..... 50

(Ne 15 .... 30)

Nm 40 .... 100

(Ne 24 .... 60)

1 - 2 dtex 1 - 2 dtex

Cylinder 5095D 5095D 5695D 666D 686D

Doffer 7300R2 7300R2 7300R2 7300R2 7300R2


Alpha 45Gradutecc

Alpha 55Gradutecc

Alpha 35Gradutecc

Alpha 45Gradutecc

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Card C 51- Graf wire, Specification Sheet for „Wide-Range“ Clothings


OE-yarncoarse

OE- yarn fineRing yarn

coarse

Ring yarnfine

Ring yarnextra fine

Manmadefibers

Blends / Swing Application

< Nm 35(< Ne 20)

Nm 25 ..... 50(Ne 15 .... 30)

Nm 40 .... 100(Ne 24 .... 60)

> Nm 80(> Ne 48)

1 - 2 dtex 1 - 2 dtex

CylinderP-1840S x 0.4

CSP-2040S x 0.4

CSP-2030 x 0.4

CSP-2030 x 0.4

CSR-2520 x 0.7

R-2530 x 0.6CS

Doffer M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R

Flats RSTO M-48/0 RSTO M-48/0 RSTO F-55/0 RSTO F-55/0 ILX M-40/0 RSTO M-48/0

C 51 ‚Hi·Per·Card‘ – Graf wire, Specifications for Productions > 70 kg / h

Set AH BH CH (F) DH EH

OE-yarncoarse

OE- yarn fineRing yarn coarse

Ring yarnfine

Ring yarnextra fine

Manmade fibers Application

< Nm 35(< Ne 20)

Nm 25 ..... 50(Ne 15 .... 30)

Nm 40 .... 100(Ne 24 .... 60)

1 - 2 dtex 1 - 2 dtex

Cylinder P-1840S x 0.4 CS P-2040S x 0.4 CS P-2030 x 0.4 CS R-2520 x 0.7 R-2530 x 0.6 CS

Doffer M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R

Flats RSTO M-48/0 RSTO M-48/0 RSTO F-55/0 ILX M-40/0 RSTO M-48/0

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3.1.4.2. Wire recommendation C60

Effective January 1 2005, the following specification sheets are approved by Rieter Machine Works, ECC andGraf as wide-range clothing sets for our C60 card.

The strategy of the sales and service departments concerning the wire sets is as follows.• Defined sets contain the specifications for: Cylinder (C), Flat (F) and Doffer (D)• Rieter makes a „house-recommendation“ according the latest findings of technology. Specific customer-wishes

in regard to supplier and/or wire type are considered during the wire selection process.

Card C 60 – ECC wire, Specifications for Production up to 120 kg/hr


OE - yarncoarse

OE – yarnfine

Ring yarncoarse

Ring yarnfine

Ring yarnextra fine

Manmadefibres

Blends /Swing

Application

< Nm 35(< Ne 20)

Nm 25 ..... 50(Ne 15 .... 30)

Nm 40 .... 100(Ne 24 .... 60)

> Nm 80(> Ne 48)

< 2 dtex < 2 dtex

C linder 5095D 5095D 5695D 5695D 472D 5586D

Doffer 7300R2 7300R2 7300R2 7300R2 7300R2 7300R2


Alpha 45Gradutecc

Alpha 55Gradutecc

Alpha 55Gradutecc

Alpha 35Gradutecc

Alpha 45Gradutecc

Card C 60 H - ECC wire, Specifications for Production > 120 kg/hr

Set A B C (F) D (F) E

OE - yarncoarse

OE – yarn fineRing yarn

coarse

Ring yarnfine

Ring yarnextra fine

Manmadefibres

Application

< Nm 35(< Ne 20)

Nm 25 ..... 50(Ne 15 .... 30)

Nm 40 .... 100(Ne 24 .... 60)

< 2 dtex < 2 dtex

Cylinder 5095D 5095D 5695D 472D 5586D

Doffer 7300R2 7300R2 7300R2 7300R2 7300R2


Alpha 45Gradutecc

Alpha 55Gradutecc

Alpha 35Gradutecc

Alpha 45Gradutecc

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Technology Handbook

Card C 60 – Graf wire, Specifications for production up to 120 kg/hr


OE - yarncoarse

OE – yarnfine

Ring yarncoarse

Ring yarnfine

Ring yarnextra fine

Manmadefibres

Blends /Swing

Application

< Nm 35(< Ne 20)

Nm 25 ..... 50(Ne 15 .... 30)

Nm 40 .... 100(Ne 24 .... 60)

> Nm 80(> Ne 48)

< 2 dtex < 2 dtex

Cylinder

P-1840S x 0.4

CS

P-2040S x 0.4

CS

P-2030 x 0.4

CS

P-2030 x 0.4

CS

R-2530 x 0.6

CS

R-2530 x 0.5

CS

Doffer M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R M-5030 x1.0R M-5030 x1.0R M-5030 x 1.0R

Flats RSTO M-48/0 RSTO M-48/0 RSTO F-55/0 RSTO F-55/0 ILX M-40/0 RSTO M-48/0

Card C 60 H – Graf wire, Specifications for production > 120 kg/h

Set A B C (F) D (F) E

OE - yarncoarse

OE – yarn fineRing yarn coarse

Ring yarnfine

Ring yarnextra fine

Manmade fibres Application

< Nm 35(< Ne 20)

Nm 25 ..... 50(Ne 15 .... 30)

Nm 40 .... 100(Ne 24 .... 60)

< 2 dtex < 2 dtex

Cylinder P-1840S x 0.4 CS P-2040S x 0.4 CS P-2030 x 0.4 CS R-2530 x 0.6 CS R-2530 x 0.5 CS

Doffer M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R M-5030 x 1.0R

Flats RSTO M-48/0 RSTO M-48/0 RSTO F-55/0 ILX M-40/0 RSTO M-48/0

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3.1.5. Clothing – grinding (When IGS is not used)

The primary indication that the clothing needs to be ground is that the nep count in the sliver has reached theupper tolerable limit.The wire condition should be visually checked using a magnifying glass of 30 to 50 powers. The tips of wornclothing appear rounded with no carding leading edge.It is then necessary to grind the clothing until a clean sharp leading edge is visible over the whole of the clothing.The grinding should be performed carefully and in small steps to prevent the formation of “burrs on the front edgeof the teeth.

Judging the Cylinder Clothing Tipsafter Grinding

The following is taken from the machine manual as a guide.

a) Is a correctly ground tooth with a sharp, clean carding edge(1). There is a good tooth shape and fine grinding marks onthe surface of the tooth.

The clothing operates at its optimum.

b) The worn radius (2) on the front edge has been groundaway only partially. A sharp edge (1) is still lacking.The fine grinding marks do not extend to the edge, theradius (2) is still bright.Grind additionally until edge is sharp.

c) Tooth with a burr on the front edge (3).This condition must be avoided at all cost!

Possible causes:

The grinding roller was pressed against the tips withexcessive force. (Grinding pressure too high)

The grinding stones are dull.

For additional grinding information refer to the machine manual.

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3.2. Licker-in

The first tuft opening action takes place at the feeding point. The matt is firmly held between the feed plate andthe feed roll and the licker-in separates fibres and tufts from the matt. The intensity of this action is dependentupon the speed of the licker-in and the setting of the feed plate. If the feed plate is set too close there will be fibredamage. As the fibres are fed, they are instantaneously accelerated to the surface speed of the licker-in, which is in the

region of 900 m/min. (licker-in circumference x rpm. i.e. diameter – 250 mm x π x 1100 rpm = 864 m/min or 14.4m/sec)

If the matt feed rate were 1.6 m/min, the draft at the feeding zone would be 540:1

Advantages of the Rieter card in the feed and licker-in zone are: The unidirectional feed arrangement which transfers the fibres to the licker-in without a rapid change of

direction which is the case with the convention feed roll / feed plate arrangement. The variety of arrangements of mote knives and carding segments around the licker-in to progressively open

the fibre tufts before they reach the cylinder.

3.2.4. Licker-in mote knives and carding elements

The licker-in region is designed to remove trash and vegetable matter. Approximately 90% of the card waste isremoved in the licker-in zone. This waste is high in trash content and is not re-usable. Preferably, it should not bemixed with the remainder of the card waste that is of higher fibre content and can be recycled for specific end

uses.

The new licker-in assembly consists of adjustment free profiles with a new patented mounting. Two cardingelements are fastened to each profile. With this innovation there is no need to adjust the carding element / licker-in distance. This reduces the assembly time when changing the licker-in and guarantees optimum runningconditions.

Basic version for cotton on the C51 Hi•Per•Card.

3.2.4.1. Standard arrangement

1. Licker-in2. Adjustable knife3. Carding element3a. Guide element4. Combi-profile

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3.2.4.2. Enlarged extraction slot

Additionally chrome-plated flat for cotton(man-made fibres, swing).

3.2.4.3. Basic version for man-made fibres

1 Licker-in2 Knife3 Carding element

The guide element can also be used and then therewill be virtually zero licker-in waste.

In the above illustrations of the C51 Hi•Per•Card, there are two knives and two profiles shown in each case. It isalso normal to use a single knife and one profile when carding short clean fibres such as cotton noil.

Additionally, for man-made fibres it is possible to use a single profile with either a single knife or a “feeding aid”can be used to replace the knife and eliminate waste being removed at the licker-in.

The degree of waste removal and cleaning at the licker-in is influenced by: the setting of the knife relative to the licker-in wire,

the size of the trash removal opening immediately before the knife, the number of knives, speed of the licker-in: higher speeds increase waste removal, but may also increase fibre damage. with heavier matt weights the feeding speed is lower and the fibre is held for a longer time in the opening

zone. This increases the opening action of the licker-in and slightly increases the trash removal but there isalso a tendency to damage fibres.

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3.2.5. Licker-in / cylinder fibre transfer

The material on the licker-in is transferred to the cylinder. At the transfer zone the licker-in wire is in the doffing position relative to the cylinder, which has a higher surfacespeed. The cylinder is travelling in the same direction as the licker-in and therefore the opening effect is small.

Generally, the ratio of licker-in surface speed to cylinder surface speed should be about 1:2. Changing the lickerin speed to maximize trash removal alters this ratio. Care should be taken to ensure that increasing the licker-inspeed to remove more trash does not compromise the overall carding performance.

The licker-in speed is linked to the cylinder speed but there are three ratio changes that can be made and therecommendations are:

Man-made fibres and blends Cylinder / licker-in ratio 2.05 (“slow” licker-in speed)

Cotton Cylinder / licker-in ratio 1.78 (“medium” licker-in speed)

Cotton with a high trashcontent

Cylinder / licker-in ratio 1.55 (“fast” licker in speed and standard for the C 51Hi•Per•Card)

Immediately after the cylinder takes the fibres they are pressed into the wire by the cylinder cover plate. The platehas to be set relative to the cylinder wire to ensure that the wire securely transports the fibres.

3.3. Carding segments TREX and TREXplus

As carding production rates have progressively been increased, it has become necessary to include additionalstationary carding segments around the cylinder. They are located between the licker-in and the flats andbetween the flats and the doffer.

In the first versions, the carding segments between the licker-in and the flats were used to progressively open upthe tufts carried by the cylinder wire before the fibres encountered the flats. Additionally, carding segments between the flats and the doffer were found to be beneficial in preparing the fibres

for the doffing action.

In the Rieter card these segments are referred to as the TREX-system.Developments of the carding elements and of suction channels located between the elements have led toTREXplus that removes dust, trash and very short fibres.

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Technology Handbook

C 51 Hi•Per•Card TREXplus

The TREXplus carding elements:

1 holder with a knife (1a) and 3 carding elements

2 holder the guide element (2a) and 2 carding elements

3 holder with 3 carding elements

4 holder with knife, guide element (4a) and 2 carding elements

TREXplus selective trash removal:

C 51 Hi•Per•Card TREXplusPre-carding zone,

1 Fibre opening,2 Dust, trash and short fibre separation.

Post-carding zone,

3 Fibre opening,4 Dust trash and short fibre separation.

The TREXplus system incorporates the toothed guidingelements that were developed to keep the good fibre onthe cylinder wire while allowing the trash to ride on thesurface and be removed at the trash slot.

The benefits of the TREXplus are:Higher efficiencies in the ring and rotor spinning operations, significantly better IPI values in the yarn.

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3.4. Flats

The primary carding action takes place between the cylinder and the flats. The fibres carried by the cylinder wiretend to move toward the flats that resist fibre movement. Many of the fibres “float” between the flats and thecylinder wire.

This “carding action”: Separates individual fibres, Opens entangled fibres, Separates and retains the neps in the flats, Frees / removes trash particles and vegetable matter from the fibres, Removes dust collected in the flat strips, Orients the fibres in the direction of the cylinder movement.

The carding surface of the flats is ground at a slight incline to allow the fibres to enter the space between the flatsand cylinder. In conventional cards this means that the flat setting and closest distances between flat and cylinderis only at the trailing edge of the flats.Rieter uses a flat design with a “Heel” that increases the degree of carding at the trailing edge.

The setting of the flats is extremely important and has to be performed carefully according the instruction manual.

3.4.4. Direction of flats movement

The flats on Rieter’s cards are moved backwards, that means the working flats move from the doffer side to the

licker-in side. This is in the opposite direction of the cylinder movement.

The advantages of backward movement are: The first four or five flats over the licker-in take up the vast majority of the trash removed by the flats. This

occurs regardless of the direction of movement of the flats. When the flats move in the backward direction, the trash taken up by the flats at the entry to the carding

zone is immediately removed from the carding zone. The fibres passing through the carding zone move passed progressively cleaner flats as they approach the

doffer. There is less tendency for impurities to be returned to the fibres on the cylinder because the last fewflats are relatively clean.

3.5. Doffer

The fibres are removed from the cylinder by the “doffer”. They rotate so that the cylinder and doffer surfacesmove in the same direction at the transfer zone.

The doffer rotates at a considerably slower surface speed than does the cylinder and consequently fibresaccumulate on the doffer wire.

The doffer speed is normally in range of 50 to 120 m/min and the cylinder surface speed is in the region of1500 m/min.

The doffer takes some of the fibres carried by the cylinder, but the majority stays on the cylinder. There is a

transfer factor in the order of 0.2 to 0.3, Fibres, on average, pass around the cylinder 3 to 5 times.

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The fibres taken up by the doffer are caught (hooked) on the wire and partially combed out by the passingcylinder wire. Consequently the fibres on the doffer have a majority of “trailing” hooks relative to the

movement of the doffer and subsequent sliver. The fibres taken up by the doffer have to be held securely by the wire and must not drop from the wire as the

doffer rotates.

The fibre transfer factor largely depends upon: the setting of the doffer to the cylinder, the type of doffer and cylinder clothing, the wire tooth geometry, particularly of the doffer, the number of points on the cylinder and doffer, the sharpness of the doffer wire, the aerodynamics at the exit region of the cylinder doffer zone.

3.6. Cylinder plates and tongue

The tongue is located between the doffer and cylinder underneath the doffing zone. It is used to minimize airdisturbance and facilitate a smooth and consistent transfer of fibre to the doffer. The tongue is pre set andnormally does not need to be adjusted. On the other hand, for certain carding conditions, re-setting may benecessary or even a modified tongue may be needed.

Under the cylinder Rieter installs cylinder cover plates that do not allow waste to be discharged. In high speedcarding the quality is better when solid plates are used and the air turbulence under the card is eliminated.

3.7. Hook formation

The doffer clothing has a limited filling capacity. It depends upon the fibre fineness and for a one-meter wide cardis limited to about 3 to 5 g/m (42 to70 grains/yard).When the filling approaches or exceeds maximum loading, the extra fibre tends to be entangled and produces acloudy web.This cloudy characteristic has poor fibre orientation and produces a weak web that can be difficult to control. Withshort staple fibres this cloudiness can be drafted out in the drawing processes and will have only a limited effect.

However, with long staple fine fibres the extra web material responds to the drawing process by forming anexcessive number of knots or neps. This phenomenon occurs with both long staple cotton and fine man-madefibres.

In general, lighter web weights/ cm² are better than heavier web weights for quality spinning. As mentioned earlier, in the doffing process, the fibres are hooked around the doffer wire and this creates“trailing” hooks. According to Morton and Yen the percentages of the various fibre shapes in the card sliver are asfollows:

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Typical fibre shapes in the card sliver

Designation Shape Approx. %

Trailing hooks Over 50%

Leading hooks 15%

Double hooks 15%

No hooks 20%

Direction of movement

No rule can be stated regarding the distribution of hooks in a cloudy web. In this case, the sliver weight and thecylinder speed primarily govern the percentage distribution of hooks.

For Rotor spun yarns and coarse ring spun yarns, fibre hooks and their distribution is of minor significance.

3.8. Sliver formation

The web on the doffer is removed by a detaching roller that has to be set to peel off the web in a smoothcontinuous action. The setting distance between the detaching roller and the doffer depends upon the web weightand the bulkiness of the fibres being carded.

A “protective plate” is provided under the detaching roller to prevent the peeled web from breaking or droppingfrom the detaching roller.

The web is then taken up by the top and bottom delivery rollers, there being a transfer roller nestled between thedetaching roller and the delivery rollers to ensure a smooth web movement.

The web emerging from the delivery rollers is gathered by the traversing cross apron that carries the fibre

assembly to the sliver-forming zone. The material first passes through a “condensing” trumpet and is then pulledthrough the compacting trumpet by the stepped rollers.From the stepped rollers the sliver is transported to the coiler.

The relative speeds of the elements of the delivery section have to be adjusted according to the delivery speedand the nature of the material being processed. The respective drafts should be set according to the instructionmanual.

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3.8.4. Sliver coiling

There are two types of coilers available: The rotating can coiler in which the coiler plate deposits the sliver coils into a can that is revolving. The planetary coiler in which the can is stationary and the coiler plate is moved to lay the coils and form the

sliver column.

In either system the setting of the coiler has to be done to prevent sliver damage, stretching, or over filling thecan. The sliver column should be 8 to 10 mm clear of the can sides to allow easy withdrawal of the sliver at theDrawframe.Needless to say damaged cans should be avoided to ensure a good quality of sliver.

3.9. Autolevelling

In modern spinning plants it is essential that the card sliver weight is controlled. The uniformity of matt weightdelivered to the card is dependent upon the chute feed system and the condition of the material being processed.Unfortunately irregularities of feed are inherent and have to be corrected at the card.

The C 51 and C 51 Hi•Per•Card can be equipped with sliver autolevelling systems. The basic system isschematically represented below.

Key:1 Input signal obtained by measuring the thickness of the matt being fed to the card.2 Input signal from the sliver delivery rollers.3 Input signal from the light sensor in the A 70 chute.

SCU control unit.

A) Control for the drive of the feed rollers in the A 70 chute.B) Inverter controlled drive to vary the feed roller speed according to the measured matt thickness and

the sliver output signal.The autoleveller can correct matt weight, but cannot eliminate faults that occur in the carding operation.

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The Rieter autoleveller acts as a mid-term leveller by measuring the matt thickness and varying the card feed rollspeed to compensate for thickness variations. Even though the system responds to short variations of matt

thickness, because the card draft is usually more than 100:1 the card sliver improvement can be seen as theCV% correction of 2 to 3 m lengths.

Adjusting of the autolevelling system must be carried out according to the instruction manual depending upon thecontrols being used.

3.10. IGS-classic

The IGS-classic was developed to solve the problem of maintaining cylinder wire in good condition. The manualoperation of grinding the clothing when the carding performance had deteriorated to below a predetermined level

is problematic. The operation is not always performed correctly; skilled technicians may not be available.The cards must be correctly ground or sharpened to ensure a good carding action. This is best carried out by theIGS-classic system in which the sharpening action is performed automatically while the card is in normalproduction.

IGS-classic

without IGSLifetime of a cylinder wire

without IGS with IGS

maximum nep level

without IGS

with IGS Classic

without IGSLifetime of a cylinder wire

without IGS with IGS

maximum nep level

without IGS

with IGS Classic

An aluminium holder mounted underneath the cylinder supports the grindstone.The IGS system is set to maintain wire sharpness throughout the lifetime of the wire. The controls areprogrammed to traverse the stone 400 times during the wire lifetime. The frequency of sharpening changesthroughout the wire lifetime. When the wire is new the interval between passes is several days, whereas whenthe wire is worn out the cycles are very frequent.

The carding action requires that the point of the wire be sharp. When the point is worn and the tip is round, thefibres tend to slide over the wire and this sliding action accelerates the wearing action. Although the IGSsharpening stone removes small amounts of the wire as it passes, the wire lasts longer because of the reducedamount of sliding fibre-wearing action.

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Wire condition throughout lifetime

With the IGS-classic the wire life is extended by 25 to 30% depending upon fibres, production rates and plantquality requirements.

The advantages of the IGS-classic are: Automatic sharpening of the cylinder wire, No wire damage or excessive grinding due to technician performance Uniformly sharp wire with consistent carding performance throughout the lifetime of the wire, Minimal fluctuation of nep and trash removal due to changes of cylinder wire condition, Increased lifetime of the cylinder wire, No machine down time required for grinding the cylinder wire.

When the wire is installed, the expected lifetime has to be entered in the program. Part way through the wirelifetime, it may become obvious that the wire is being sharpened too frequently. If this occurs, it is possible toenter a longer wire lifetime and the program will automatically adjust the times between the remaining cycles.

The sharpening stone should be changed when a new wire is put on the cylinder.

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3.11. IGS top

The success of the IGS-classic led to the development of the IGS - top that automatically maintains thesharpness of the clothing on the flats.

The IGS – top is installed over the returning flats after they have been cleaned.

IGS – top Automatic Flat Sharpening System

Periodically the system is activated and the flats are raised one at a time and pressed against the rotatingabrasive brush.

Short bristles sharpen the points of the pins.Longer more flexible bristles work against the sides of the pins to keep the leading edges sharp.

As the pins wear down, the form of the pins is maintained by the combined actions of the long and short abrasivebristles.

3.12. Flat setting

The IGS-classic and IGS – top eliminate manual grinding however, as the clothing wears it is still necessary toperiodically set the flats to maintain optimum carding performance.

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3.13. Trash removal and classification

By using the MDTA trash and dust analyzer the following results have been established as a means ofclassification.

Trash in cotton bales:

Up to 1.2% very clean (e.g. El Paso)

1.2 to 2.0% clean (California)

2.0 to 4.0% average (Texas, Africa)

4.0 to 7.0% trashy (Pakistan)

> 7.0% Very trashy

Trash in card sliver

Up to 0.05% very clean

0.05 to 0.10% clean

0.10 to 0.15% average

0.15 to 0.20% fair

> 0,20% high

3.13.4. Effect of overall system cleaning

The cleaning efficiency of the card ranges from 80 to 95%.

From bale to sliver the overall trash removal is in the range of 92 to 99%. This means that from cotton with a 3% trash level the card sliver trash content would be in the range of 0.25% to 0.03%For the card to be able to reduce the trash level to 0.03% when working at the high performance of 95% trashremoval, the blowroom has to reduce the trash level in the matt to 0.6%. This means that the overall blowroomcleaning efficiency has to be 80%, which is also very high.

NOTE: The overall cleaning efficiency is NOT found by adding individual machine cleaning efficiencies. Forexample, in the blowroom, if the first cleaning machine removes 40% of the trash and the second cleaningmachine removes 50% of the remaining trash, the overall cleaning efficiency is only 70%

Calculation: Using cotton with original trash content of 3%.

- 1st cleaner at 40% efficiency removes 3 x 40% = 1.2%, leaving 1.8% trash.- 2nd cleaner at 50% efficiency removes 1.8 x 50% = 0.9% leaving 0.9% trash.- Total trash removed = original 3% - remaining trash of 0.9% = 2.1%.

Overall cleaning efficiency is 2.1% x 100 = 70%

3.0%

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4. Recommendations

4.1. Process recommendations

The performance of the card is dictated by the quality and condition of the supplied material, the condition of thecarding elements, the production rate and most importantly the setting of the components.The settings have to be optimized by observing the running performance as well as by testing the sliver quality.

The procedures for setting the components of the card and suggested starting points are included in the machinemanual.

In some cases there may have been tests previously conducted and they should be used as a reference.

The following points are presented for a better understanding of some of the carding principles.

4.1.4. Matt weight and condition

The best matt weight is when the carding draft is in the optimal range. For most fibres a carding draft of 95 to125 is targeted.

It is important that the matt should be consistent from side to side. Lengthwise variation can be corrected by

the levelling system but irregularities across the matt cannot be accommodated. Holes or thin places in thematt are problematic because the fibres are not fully controlled at the feeding zone.

Matt draft should not be too low with buckled matt feed. Nor should it be so high as to pull thin places. Draftsare available from 1.19 to1.37.

A test for buckling is to remove tufts of fibre from the matt as it is being fed and see if the matt tends to liftwith the tufts. If it does lift, increase the tension.

A more consistent matt is produced when the chute feeding system is running at a high production ratio. Itshould be running for more than 90 percent of the time for best results.

The material should be well opened with no compacted or entangled material.

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4.1.5. Feed plate setting

The adjustment of the feed plate (feed trough) is normally made according to the fibre staple length.The recommendation from the manual can be used as an approximate guideline:

Adjustment of Feed TroughDetermination of nipping point “D” / carding point.

Care should be taken to see that fibres are not being over controlled at the feeding point. If the longest fibres arebeing broken, the feed plate setting should be opened up.

4.1.6. Licker-in and cylinder speeds ranges by fibre types

The following table shows the C 51 Hi•Per•Card typical speed ranges for man-made fibres, cotton and trashycotton. This information should be used in conjunction with the charts below referring to production rates.

Licker-in speed (rpm) Cylinder speed (rpm)

Synthetics and Blends 900 to 1300 300 to 450

Cotton 1610 to 2160 450 to 600

Trashy Cotton 1000 to 2000 300 to 600

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The following chart shows the suggested cylinder speeds for cotton and man-made fibres at different productionrates on the C 51 Hi•Per•Card,

Information regarding the C 51 card is included in the machine manual.

Cylinder Speeds rpm

Care should be taken to be sure that the action of the licker-in is not too aggressive. The staple length and theshort fibre content of the matt and the sliver should be compared. If the SFC of the sliver is two-percentage points greater than in the matt then fibre damage is occurring and

the licker-in speed and the feed plate setting should be checked.

4.1.7. Basic settings around the cylinder

The standard values for settings around the cylinder are included in the machine manual. A typical example fromthe C 51 manual is shown below. Doffer / Cylinder Settings for Cotton and Blends Cold Machine

FT 160 FT 330FT 660FT 160 FT 330FT 660

0.90

17.00

1.00

0.35

1.50

1.20

0.901.20

0.80

2.50

0.901.20

0.15

0.20

0.150.20

1.50 Left

2.00 Right

0.90

17.00

1.00

0.35

1.50

1.20

0.901.20

0.80

2.50

0.901.20

0.15

0.20

0.150.20

1.50 Left

2.00 Right

In the constant effort to maximize nep and trash removal there is a tendency for the customer to request closersettings of the flats, segments and doffer relative to the cylinder. Great care has to be given to very close settings,with attention being given to:

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Setting when the card is warm or cold,

Cylinder speed, if the speed is increased the warm running settings become closer, The condition of the clothing on the flats, cylinder and doffer. It may be prudent to “dress the clothing before

closing up on the settings. If flats are changed or new clothing installed it is necessary to dress the flats before adjusting to tight

settings. After re-clothing the card, it should be “run –in” before going to high speed and close settings.

4.1.8. Doffer

The following chart is taken from the C 51 Hi•Per•Card manual and shows the basic cold machine settings of thedoffer to the cylinder for a production range of 50 to 90 kg/hr.

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4.1.9. Delivery section

A schematic arrangement of the components of the delivery section is shown below. The relative speeds of thevarious rolls are adjustable by changing the appropriate draft gears. Visual checks of the web condition are thenormal way to judge the set-up.

Drafts in the delivery section

Key:7 Doffer 12 Bottom delivery roll 13 Cross apron9 Detatiching roll 11 Upper delivery roll 14 Stepped roll10 Transfer roll

Alterations to the change gears influence the draft ranges.

Change of gear Gear to be adapted

W 1 W 3

W 4 W 2

In general the tension drafts in the delivery section have to be increased with higher delivery speeds to obtain asmooth transition from the doffer web to the sliver. Details of the drafts between components are included in themachine manual.

4.1.10. Carding synthetic fibres

Processing synthetic fibres on high-production cards requires “high performance fibre finish” to adequatelylubricate the fibre and provide satisfactory antistatic properties. Heat is generated by the carding action and istransmitted to the card clothing. Overheated clothing encourages static charging of the fibres, making it difficult todetach the web.

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Increasing the moisture content of the surrounding air by increasing the humidity can reduce electrostaticcharging of the fibres. However this should not include increasing the room temperature. Try to keep the fibres

from over heating.

When the synthetic fibres are well opened in the blowroom it is easier to process them at the card. With well-prepared fibres it is possible to operate the cards with wider flat settings, hence the friction forces and staticcharging are minimized.

The effectiveness of the fibre finish varies. In most cases it is at its best between two to three weeks after thedate of manufacture, after which it deteriorates steadily. It is preferable to have the fibre delivered as needed andnot to store bales for several months.The rate of finish degradation varies from one supplier to another and in many instances from batch to batch fromthe same supplier. Consequently, changing from one batch to another should be phased in over several days.

4.1.10.1. Fibre crimp

The crimp of synthetic fibres affects the production rate of the card. Strong fibre crimp gives the card web bettercohesion and web stability. To set a strong fibre crimp, the fibre producers use higher pressures andtemperatures in the fibre production process. The additional heat treatment usually means a loss of fibre strengththat is translated into a loss of yarn strength. Consequently, these high crimp fibres are not used in high strengthapplications such as sewing threads. To card low crimp fibres the production rates have to be reduced andsometimes the card web weight has to be increased.

4.1.10.2. Speeds and settings on the card

The following are general statements regarding cotton type fibres, i.e. fibres of 1.5 den and of staple length up to11/2″ (40 mm): Licker-in speed, - Cylinder speed, - Flat settings, - Clothing has to be specified for the particular needs.

For blends of cotton / synthetics, the type of card clothing can be closer to that of the cotton clothing, but it is still

necessary to use a “combination” wire which can, if necessary be used for blends or 100% cotton.

The carding of longer synthetic fibres of coarser denier, (≥2.5 den x ≥ 60 mm) associated with “wool – type”applications require that the card settings be opened up and speeds reduced.

In general, it can be said that if there are dust deposits in and around the card, the settings are too close and /orthe speed is too high. The dust collected on the machine is primarily fragmented fibre polymer and is frequentlywrongly referred to as fibre finish.

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4.2.1. Air pressure

The compressed air requirements of the cards are: Supply pressure: 7 to 8 bar, Working pressure: 6.0 bar, Air consumption:

Card 0.1 Nm³/hIGS-top 0.075 Nm³/h

4.2.2. Exhaust air / Suction

The suction to the cards depends upon the waste removal system and whether it is by local suction or bycentralized suction, but the common localized requirements are the same.

Suction for C 51 and C 51 Hi•Per•Card

Exhaust air – volume 3000 Nm³/h

Partial vacuum at interface- 50 Pa for local or –1000 Pa for central suction

Waste transport from the licker-in zone

Volume of air 0.5 m³/s

Suction cycle (+/- 1 min) 12 min (C 51) or 6 min (C 51 H•P•C)

Suction duration 6 seconds

Waste transport from the carding zone

Volume of air 0.5 m³/s

Suction cycle 6 min, ( +/- 30 sec)

Suction duration 9 seconds

4.2.3. Room conditions

The water content of the air in the card room should be sufficient to control static build up and maintain fibrestrength, but not so high as to accentuate any sticky characteristics of the fibres.It is also necessary for the air to be somewhat cooler when carding synthetic fibres. Increased heat can lead tofibre damage and deposits on the machine elements.

For some specific synthetic fibres special conditions are suggested by the fibre supplier and should be followed ifpossible.

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The following are some guidelines:

Fibre Water content Temperature Humidity

Cotton 9 – 12 g/kg 24 – 28 C 46 – 54 % r.f.

Polyester 9 – 12 g/kg 22 – 28 C 48 – 60 % r.f.

CO / PES 9 – 12 g/kg 22 – 28 C 48 – 60 % r.f.

Viscose 9 – 12 g/kg 22 – 28 C 48 – 60 % r.f.

Acrylic 9 – 12 g/kg 22 – 28 C 48 – 60 % r.f.

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5. Troubleshooting

5.2. Impact of machine settings

The complex function of the card requires that the settings and conditions of the elements be correct. Thefollowing are a few examples of what can happen when the settings are incorrect:

5.1.1. Feed roller to licker-in

Setting too close: - Loss in yarn strength and elongation,- Fibre damage, increased short fibre content.

Setting too wide: -Thick places in the yarn, (increased CV%)- Insufficient trash removal.

5.1.2. Feed trough (plate) nipping distance (D)

Setting too close: - Fibre damage,- Loss in yarn breaking strength,

Setting too wide: - Thick places in the yarn, (increased CV%)- Insufficient trash removal.

5.1.3. Licker-in to cylinder

Setting too close: - Possible fibre damage,- Danger of early cylinder wire damage.

Setting too open: - Possibly excessive flat strips.

5.1.4. Flats to cylinder

Settings too close: - Loading of the cylinder,- static accumulation,- damage to flats and cylinder wire,

Settings too wide: - High nep count in the sliver,- insufficient fibre orientation,- insufficient trash removal,

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5.1.5. Cylinder to doffer

Settings too close: - Damage to the cylinder and doffer wire, “Facing”.

Settings too wide: - Loading of the cylinder,- uncontrolled fibre transfer,- high nep count in the sliver- cloudy web.

5.1.6. Tongue to cylinder and doffer

Tongue to close: - Fibre collects on the tongue and causes the web to break. Tongue should be

lowered to increase the distance from the nip and swung to obtain a clean fibretransfer.

Tongue too open: - For waste and short fibres the tongue may have to be set closer to obtain clean fibretransfer.

5.2. Reasons for sliver breaks

5.2.1. Trash accumulations at the condenser

Obviously worse with dirty cotton. The card has to be cleaned frequently to prevent trash build-up. Excessive short fibres cause accumulations. - Check fibre in the laydown and waste handling

procedures as well as possible card related reasons. When the doffer wire is not sharp the short fibres and fly become “airborne” and contaminate the

delivery system. Any doffer wire that does not hold the fibre web creates fly under the doffer and dust in the take-off area.

5.2.2. Irregular fibre transfer between doffer and stepped rollers

Check the draft settings of the transfer rolls to ensure sooth web transfer. If necessary revert to the basicsettings and adjust until the web is “quiet”.

5.2.3. Bad doffer condition

As mentioned above when the wire is not sharp the fly is increased, the doffer wire can be contaminated with trash particles embedded in the wire. If this is so, it is

necessary to manually brush the doffer until it is clean. if the wire is loaded with fibre finish due to some “off quality” fibre, try to brush it clean. If this does not

work, it may be possible to process some coarse easy to run fibre that will clean the wire by running.

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5.3. Neps in the sliver are too high (Corrective actions)

When the neps in the sliver are too high and have to be reduced it is important to check with the lab and the plantto see what is the recent history of nep levels.

5.3.1. Material being fed to the card

Questions to be answered: Has there been a change of raw material? Has the nep level in the fibre increased? Has the fibre fineness changed? (Fine immature fibres create neps in processing), Has there been a change of fibre type or quality?

Has the management of fibre waste been modified? Is the bale laydown in control to prevent accumulations of troublesome fibres? Is there control over the processing of re-workable waste? Sometimes the night shift feeds extra waste

to “clean up the place”. Is the humidity too high in the blowroom?

5.3.2. Consider the card room!

Is the nep level consistent from all cards? Do the cards from one line create the “nep problem”? Is the high nep count limited to a group of cards or a few cards? Are there any cards producing sliver of acceptable nep level? Is there an obvious reason for the variation in the levels between cards? Have the cards been well maintained? Has the production rate been increased?

Determine the detailed settings of cards that are performing satisfactorily. These settings can be used as a guide.

5.3.3. Suggested procedures and corrective actions

Check the nep level of the matt,

Check the nep level of the delivered sliver, Calculate the card nep removal rate. …% to ..% Good, …% to …% should be improved.

Removal rate = Neps in matt – neps in sliver x 100 %Neps in matt

NOTE: The nep removal rate is dependent upon the production rate If the nep removal rate is too low proceed as follows. Check the flat settings, it is critical that they are correct. – Closer settings for finer fibres. Check the condition of the clothing on cylinder and flats. Check the cylinder speed. Action: Correct those aspects that are not in order,

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Grind or touch up the clothing and / or re-set the flats. Check the results!

Check the TREX or TREXplus fora) Knife settingb) Segment setting and condition.

Correct if necessary. Optimize the speed of the flats for effective nep removal. The higher speed of flat movement will remove

more neps, but it will increase the quantity of flats strips removed. If this is effective, it is necessary todiscuss this option with the plant personnel to see if it is an acceptable action.

Increase the cylinder speed but stay within the limits of the fibres being processed.NOTE: Take care that the settings on the machine are such that the increase in cylinder speed can betolerated.

Check the nep level in the sliver. ALSO check the yarn test values to be sure that other problems are notbeing created.

Adjust the feed plate, licker-in speed and the settings of the knife to increase the removal of seed coatfragments and trash.

NOTE: The use of very close settings can lead to fibre damage, premature wear of the clothing and theincreased susceptibility of the clothing to be damaged in use.

5.4. Trash in the sliver is too high

The background to the subject of trash should be treated in the same way as outlined for neps. For the potentialimpact of the material being fed to the cards follow the respective points. For the situation in the card room followthose points.


Check the trash level of the matt, Check the trash level of the delivered sliver, Calculate the card trash removal rate 60 % to 90 % Good, less than 70 % should be improved.

Removal rate = Trash % in matt – Trash % in sliver x 100 %Trash % in matt

If the trash removal rate is too low, check and correct the following.

Check /correct the condition of the clothing on the:Licker-in,TREX elements,Cylinder.

Check / correct the settings of:Knives on the licker-in, especially the first knife,Knives of the TREX,Flats to the cylinder, - standard settings are recommended

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Check / optimize the speeds of:

Licker-in, - select the speed ratio corresponding to the type of cotton.Cylinder, - the speed should be consistent with the production rate.

Check the influence of increasing the speed of the flats. If positive, inform plant personnel. Check /correct the waste suction system. Be sure that there are no chokes or bad connections.

5.5. Short fibre content of the sliver is too high

The background to the subject of short fibre content (SFC) should be treated in the same way as outlined forneps. For the potential impact of the material being fed to the cards follow the points in section 6.3.1. For thesituation in the card room follow the points in section 6.3.2.

As a guideline the SFC in the sliver should not be greater than that of the matt. The card removes short fibres inthe flat strips and waste, but it also creates a similar amount by the carding action.


To minimize the SFC:

Set the feed plate according to the staple length, New wire or clothing is aggressive and damages fibres. Speeds should be reduced during the running –

in period. If the matt contains entangled fibres and lumps the SFC is increased. Check the characteristics of the

matt and fibre in the blowroom. Ensure that the TREX settings are correct. Check to see that the card clothing is correctly specified and installed. Check the flat settings. If the flats are set too close to the cylinder, fibre damage can occur. Increasing the flat speed will increase the removal of the short fibre, but there is also an increase in

overall flat strips.

5.6. Improving the sliver uniformity

The main influences of sliver uniformity are: the condition of the matt, the flat settings, the condition and settings of the doffer, the performance of the delivery section, doffer to the stepped rolls, incorrect or insufficient blending, variations in the amount of added reworkable waste.

Even though the card is equipped with an autoleveller it cannot make corrections for the small holes or lumps inthe matt. Neither can it make a correction for any variation created within the card or the delivery section.Those irregularities that show up in the spectrogram can be addressed by identifying the defective componentand making the necessary correction.

To otherwise improve the sliver uniformity it is necessary to visually identify the causes and then make therequired adjustments.

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Matt condition:

The matt consistency is primarily determined by the function of the blowroom equipment and the chute feed.

If the matt is lumpy or with holes or has entangled fibre clumps: Check the material being fed to the A70 chute feed to see if there is any sign of entangled or roped fibre that

cannot be opened by the opening roller in the chute. These problems can occur in most machines and in thefibre transportation pipes.

Moisture accumulation in the pipes can cause chokes that lead to entangled and “ropy” material. Check the condition of the components in the Chute feeding machine. Damaged elements or rough places

will interfere with the smooth flow of fibres. Check that the control system is functioning correctly with a high percentage of running time.

Observe the consistency of the fibre in the lower chute to see if there is any obvious problem such assticking.

Check the condition of the pan between the chute delivery rolls and the card. If the pan is damaged orcontaminated correct the situation so that the fibres slide easily.

Check the matt tension, - not too loose and bulging nor too tight and stretching.

If the material is not flowing smoothly through the card:

Check the flats exit zone to see if fibres are being lifted from the cylinder by the flats. If so, adjust thesetting of the cylinder plates.

Check the transfer of the fibres from the cylinder to the doffer. Use a lamp to illuminate the area underthe card and observe the stability and uniformity of the fibres on the doffer. If there are excessiveairborne fibres bridging between the doffer and the tongue, corrective action has to be taken.

Check the condition of the doffer wire; it may need to be sharpened. Check and adjust the tongue to control the air turbulence. Check the condition of the tongue to see if there is damage or if it is the appropriate type. Check the setting of the doffer to the cylinder

If the material is not flowing smoothly through the delivery section:

Check the web of the detaching roller and transfer roller by using a lamp to illuminate the fibres. If thefibres are accumulating or rolling, the associated drafts have to be adjusted.

Examine the condition of the detaching roller, transfer rollers and the delivery rollers to be sure that theyare not causing fibres to hang or tag.

Check the condition of the cross apron. It should not be damaged or contaminated. If it is, replace it orclean it thoroughly of any contamination.

Check to see if the card web is being correctly collected and transported by the cross apron. The tensionmay have to be adjusted depending upon the fibres and the delivery speed.

Check the atmospheric conditions in the room. The moisture content of the air may be too high for stickycotton or too low for synthetic fibres. If possible follow general guidelines. If sticking or static remains aproblem, refer to the fibre producer’s recommendations.

Check the condition of the sliver in the cans:

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The coiler tube must be in good condition, burrs or split seams cause fibre tags and bad runningconditions.

The coiling tension should be adjusted to prevent sliver stretching, or “kinked” sliver. The sliver cans should not be damaged causing fibres to tag in the coiling action or in the Drawframe

creel as the slivers are withdrawn. There should be a clearance between the can sides and the sliver column.

5.7. Impact of preceding processes

The carding operation dramatically transforms the matt into a sliver, removes almost all of the trash and most ofthe neps at increasingly higher production speeds. However, it is not a panacea for the spinning plant. Thecarding operation is very dependent upon blowroom supplying consistent, well-prepared cleaned and opened

fibre.

Each phase of the blowroom line has an impact on the card performance or card sliver quality.

5.7.1. Bale laydown

The consistency of the fibre properties is essential.

Waste fibre or low quality grade fibre has to be very carefully metered.

Uncontrolled quantities of immature cotton create surges in the nep levels of the sliver. If the remains of bales are laid on top of the new bale laydown, they are fed as to the blowroom as

loosely packed fibres that continue to have a lower density throughout the process. This impacts thematt density as it is fed to the card

Concentrations of problematic bales, such as sticky cotton, in the laydown will not be adequatelyblended in the blowroom. This can lead to localized high levels of contaminants that will cause the cardto malfunction

5.7.2. Opening and cleaning

The opening and cleaning functions are an integral part of the system. The fibres have to be cleaned adequatelyand consistently to enable the card to perform satisfactorily.

If the trash is not removed to the required level in the blowroom, the card sliver trash content willincrease proportionally.

Trash and waste sucked back into the cleaned material creates very high surges of contaminants thatcannot be removed by the card.

The sliver quality suffers and it could appear that the card is not performing well. Machines that tend to lap or develop fibre tags supply inferior material to the next machine.

Unfortunately, the entangled fibres do not get opened before they reach the card. This material cancreate defective sliver and, in the worst case, cause damage to the card clothing.

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5.7.3. Fibre transportation

Fibres that are entangled during transportation from one machine to another create problems in carding. Fibre handling fans must be in good condition. Damaged blades create fibre neps. Bad pipe seams cause fibres to hang and produce entangled material that cannot be carded well. Long transportation pipes or a high number of pipe bends can result in fibre rolling in transit. The result

is an increase in neps and fibre damage at the card. The machines in the blowroom should operate as close to continuously as possible and always be able

to adequately supply material to the card line.

5.8. Interpretation of spectrogram information

A spectrogram peak in the card sliver frequently corresponds to the circumference of a roller or pulley x the draftsbetween that element and the coiled sliver.

The following is a list of some components and their corresponding circumferences:

Component Diameter (mm)Circumference

(mm)

Feed roller 100 314

Licker-in 253 795

Cylinder 1290 4051

Doffer 500 1570Detaching Roller 120 377

Delivery Roller 80 251

Cross Apron Drive 100 314

Step Rolls 82 258

Another useful approach is to use the “rpm method” to locate a component causing a peak.

When the spectrogram peak wavelength is divided into the delivery speed of the card the rotational speed of thecomponent causing the defect is identified.

Card delivery speed in inches/min (cm) = rpm of the componentSpectrogram peak in inches (cm)

As an example: If the card is running at 150 m/min and a spectrogram peak shows up at 39 cm (15.4″), the speedof the faulty component is:

150 m/min = 384 rpm0.39 m

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The cylinder speed was 380 rpm and was the cause of the problem.

NOTE: Contaminated timing belts can cause spectrogram peaks at various wavelengths. Therefore, clean the

machine first and re-check the sliver before starting to trouble shoot. Coiler peaks should be checked by:

a) Producing a sample onto a hand held board and checking for peaks. If they persist, thenb) Produce sliver directly from the stepped rollers to identify whether the cause of the peak is coiler related ormachine related. (Unfortunately this means removing the coiler plate.)

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5. Drawing Process

1. GENERAL INFORMATION 4

1.1. Introduction 4 1.1.1. Product concept Rieter 5 1.2. Principle features 6 1.2.1. Materials: 6 1.2.2. Doublings: 6 1.2.3. Creels: 6 1.2.4. Draft: 6 1.2.5. Delivery speeds: 6

1.2.6. Quality monitoring: 6 1.2.7. Automatic can changer 7 1.2.8. Autolevelling (Optional) 7 1.2.9. CANlink (Optional) 7 1.2.10. CANlog 7 1.2.11. CUBIcan 7

2. TECHNOLOGICAL FUNCTIONS 8

2.1. Introduction 8 2.2. Influence of fibres 8 2.3. Number of drawing processes 9

2.3.1. Single process drawing 9 2.3.2. Two process drawing 9 2.3.3. Drawing for combed yarns 9 2.3.4. Three process drawing for Drawframe blends 10 2.3.5. Three process drawing for air jet and Vortex spinning 10 2.4. Sliver quality 10 2.4.1. Sliver weight 10 2.4.2. Sliver evenness CV% 11 2.4.3. Effects of close roller settings 12 2.4.4. Spectrogram 13 2.4.5. Sliver characteristics 14 2.4.5.1. Appearance of coiled sliver 14 2.5. Sliver cohesion 14

3. MACHINE ELEMENTS 15

3.1. Sliver feed 15 3.1.1. Creel height 15 3.1.2. Block creeling 15 3.1.2.1. Random creeling 15 3.1.3. Sliver splicing technique 16 3.1.4. Static creel 16 3.1.4.1. Power creel 16

3.1.5. Sliver in-feed and jockey rolls 17 3.1.5.1. Sliver tension 17 3.1.6. Sliver feed to the scanning rollers 17

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3.2. Scanning rollers to drafting system 18 3.2.1. Sliver tension 18

3.2.2. Sliver spreading 18 3.3. Drafting 19 3.3.1. Critical factors affecting the drafting action 19 3.3.2. Roll setting 20 3.3.2.1. Setting tip 20 3.3.2.2. The main draft zone roll – setting (H V D) 20 3.3.2.3. Break draft zone - roll setting (V V D) 20 3.3.3. Draft distribution 21 3.3.3.1. Break draft zone - Draft (V V ) 21 3.3.3.2. Main draft zone – Draft (HV) 21 3.3.3.3. Examples of roll and draft settings 22 3.3.4. Roll pressure 23

3.3.5. Speed 23 3.3.5.1. Effects of excessive speed 24 3.3.6. Cot condition 24 3.3.7. Dust, fly and waste removal 25 3.3.8. Sliver formation 26 3.3.9. Web funnel insert 26 3.3.8. Condenser (Trumpet) 28 3.3.9. Tension draft between front rolls and calender rolls 29 3.3.10. Calender roll pressure 29 3.4. Coiling 30 3.4.1. Coiler tube 30 3.4.1.1. Coiler tube inside diameters 30 3.4.2. Sliver deposit 30 3.4.3. Coiler settings 30 3.4.3.1. Coiler speed 31 3.4.3.1.1. Correct coiler speed 32 3.4.3.1.2. Coiler speed too low 32 3.4.3.1.3. Coiler speed too high 32 3.4.4. Sliver coils per can revolution 33 3.4.5. Can eccentricity 33 3.5. Autolevelling 33 3.5.1. Autolevelling principle 34 3.5.2. Pre - Autolevelling setting 34

3.5.3. Autoleveller adjustments 34 3.5.3.1. Scanning rollers 35 3.5.3.2. Sliver funnel 36 3.5.3.3. Scanning roller pressure 36 3.5.4. Desired target sliver weight 37 3.5.5. Levelling Action Point (LAP) 37 3.5.5.1. Values of levelling action points 38 3.5.6. Levelling intensity 39 3.5.6.1. Sliver test 39 3.5.6.2. Sliver test protocol (example) 39 3.5.7. Material correction factor (Menu 20.3.3). 40 3.5.8. Autoleveller set-up procedures at lot change 40

3.6. Online quality monitoring 42 3.6.1. Rieter Quality Monitor (RQM). 42

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3.6.2. Zellweger (UQM) 42


4.1. Suggested settings for various spinning systems. 43 4.2. Combed ring spun yarns 43 4.2.1. Pre comber drawing 43 4.2.2. Post comber drawing 43 4.3. Rotor spun yarns 44 4.4. Air jet spinning (MJS) and Vortex spinning (MVS) 44 4.4.1. Suggested start-up check list for MJS and MVS 44 4.5. Air requirements 46 4.5.1. Compressed air 46 4.5.2. Exhaust air / suction 46

4.5.3. Room conditions 46

5. TROUBLE SHOOTING 47

5.1. The machine 47 5.2. The material 47 5.3. Machine component compatibility 47 5.4. Basic sliver quality check 48 5.4.1. Uniformity 48 5.4.2. Sliver spikes 48 5.4.3. Visible waves in the diagram 49 5.5. Spectrogram drafting waves 49

5.5.1. Sliver mass waves are caused by: 50 5.5.1.1. Break draft zone 51 5.5.1.2. Main draft zone 51 5.5.2. Drafting system pressure 52 5.5.3. Levelling action waves 52 5.5.4. Sliver tension waves. 53 5.5.5. Sliver delivery tension waves. 53 5.5.6. Coiler tension waves 53 5.6. Spectrograms of mechanical and periodic faults. 54 5.6.1. Draft roller defects 54 5.6.2. Use of gearing diagram to relate components to WL 56 5.6.3. Spectrogram peaks of scanning rollers and drafting system 57 5.6.4. Periodic faults due to dirty or defective timing belts / flat belts 58 5.6.5. Periodic faults due to guide and tension rollers 60 5.6.6. Periodic faults of coiling and can filling 61 5.6.7. Causes of 40 and 50 cm Spectrogram Faults. 62 5.6.7.1. Faults of 40 and 50 cm WL faults due to mechanical parts 62 5.6.7.2. Faults of 40 and 50 cm WL due to electronic components 63

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1.1. Introduction

This chapter on drawing will cover the fundamental aspects that apply to all Drawframes in the Rieter line.However additional considerations will be given to the autoleveller Drawframe RSB D 30.

RSB Drawframe

Key:1. Sliver creel 3. Drafting system 5. Evened and levelled sliver2. Scanning roller 4. Delivery discs 6. Sliver deposit

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1.1.1. Product concept Rieter

The drawing operations are extremely important in the yarn manufacturing process in that they improve the sliverquality:

Prepare and refine the sliver for the yarn spinning steps by aligning the fibres in the sliver Reduce sliver to sliver variations by combining, or doubling, several slivers and drafting them into one

blended sliver, Establish the yarn count. Normally, drafts in subsequent steps should not be adjusted to accommodate

for variations in sliver weight. Reduce yarn count variation by the use of a short-term autoleveller.

On the other hand, any fault created by the Drawframe cannot be corrected and will result in processing problemsand/or yarn and fabric defects. Such faults include:

Incorrect sliver weight.

Compacted splicings. Drafting waves. Clearer waste.

To monitor the product delivered at the Drawframe a sliver quality control monitor can be used. These are beingwidely accepted because one defective machine can produce up to 250 kg/hr of bad sliver and this can be spreadthroughout the plant creating a major problem in a short period of time. Several years ago, the single deliveryDrawframe was successfully introduced for high-speed operation. Previously, there were two and four deliveriesper machine. As production rates increased, the machine efficiencies were reduced because all of the deliverieson a machine stop when one delivery is stopped for any reason. The use of the single delivery machine can resultin efficiency gains of 10 to 15 %.Two delivery Drawframes are still used where floor space is limited or where the sliver supply is very consistentand the creel cans are relatively large. The following is from the sales information and shows the advantages ofsingle delivery drawing.

Advantages of single delivery

: efficiency

100%

100% 90%

90% 80%

80%70%

70% double delivery delivery speed

400 800

single delivery

double delivery

much higher efficiency

more flexibility

quick can changing

best accessibility

can changer 1000 mm

m/min 1200

1200 m/min

400 800

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1.2. Principle features

1.2.1. Materials:

Cotton, man made fibres, wool, recycled fibres and blends.Fibre length up to 80 mm staple.Total feed weight from 12 to 50 ktex ( 280 to 705 grains /yard).Delivery sliver weight from 1.25 to 7 ktex ( 18 to 100 grains/yard).

1.2.2. Doublings:

Normally 6 to 8, but for slivers of very short fibres, such as comber noil or regenerated fibres, a draft ofapprox. 4 may be maximum and consequently the doublings may be as low as three (3).

1.2.3. Creels:

Static creel (pull over) with stop motions. Power creel with positively driven feed roller and stop motions.

1.2.4. Draft:

Total draft (V) is 4.5 to 11.7 depending upon the materials and the requirements of the subsequentprocesses.

Break draft (VV) from 1.05 to 2.20 depending upon fibres and the input material. Pneumatically loaded 4 over 3 drafting system with pressure bar. Automatic top Roll pressure release to eliminate flat spots on the top rolls and reduce roller lapping. Simple adjustment of the top rollers.

1.2.5. Delivery speeds:

Delivery speed from 250 to 1000 m/min. in increments of 50 m/min depending upon materials andsubsequent processes.

Programmable slow speed start up after can change.

1.2.6. Quality monitoring:

Sliver quality monitoring at the delivery. Prevents “off quality” production by stopping the machine when pre-set tolerances are exceeded. Provides sliver quality data. Integrated Dust Extraction

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Dust and very short fibres are liberated as a result of drafting. The removal of dust and fly is critical to theoperation of the Drawframe. Accumulations of dust and fly create sliver and yarn defects. The machines exhaust

to: To central filtration system. Self contained suction system. Removes dust from: Rake and feeding rollers, Sliver feed zone to scanning rolls, Above the drafting system, Through the drafting zone.

1.2.7. Automatic can changer

Can diameters from 225 mm to 1000 mm ( 9 to 40 inches) Can height from 900 mm to 1500 mm ( 36 to 60 inches)

1.2.8. Autolevelling (Optional)

Precise measuring and electronic open loop levelling device for short, medium and long term sliverweight control.

Tongue and groove scanning rolls, Digital signal processor responding to measurements taken every 1.5 mm of fed sliver. Dynamic Servo drive to vary the main draft

1.2.9. CANlink (Optional)

Two or three Drawframes are linked together in series. Minimizes sliver damage by can handing, Minimizes operator related machine downtime. Increased machine efficiency.

1.2.10. CANlog

Automatic can feeding from trolleys Automatic trolley traverse Can delivery onto trolleys

1.2.11. CUBIcan

Coiling into rectangular cans Compact can filling by combined longitudinal and transverse movements. CUBIcans contain 20% more sliver per square meter of floor space than round cans.

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2. TECHNOLOGICAL FUNCTIONS

2.1. Introduction

Every aspect of the Drawframe and the movement of the fibres can have an impact on the technological aspectsof the delivered sliver. The challenge is to produce fault free high quality sliver at near maximum productionspeeds.The overall sliver quality is determined by:The type and quality of the fibres being processed,The machine condition and process control of previous operations,The processing system variations such as combing, multiple drawing steps, and the blending techniques fordifferent fibres.The results will be different for each of the many variables, but each will have an optimal drawing set up.

Unfortunately, any defects in the sliver leaving the finisher Drawframe are going to cause subsequent processingstops or a yarn / fabric defects. The primary problems are associated with either the machine condition operatorpractice or the machine settings and include:Drafting conditions that create uncontrolled sliver thick/thin places, clearer waste from the drafting rolls anddrafting waves.Uncontrolled sliver stretching in the coiling action, or any sliver stretching that cannot be removed by anautoleveller.Sliver tension, throughout the machine should be low. Establish the tension by finding the point at which it is just

too low and then increase it by one step.Sliver contamination due to the release of accumulated dust and fly.Sliver tags produced by rough spots in the sliver path or by defective cans.Damaged sliver caused by bad operator handling techniques.

2.2. Influence of fibres

The basic rules are:Long, fine fibres of uniform length can be drafted at the high end of the draft range, carded cotton and blendsshould be limited to a maximum draft of eight.With very short regenerated fibres the draft should be limited to four, and only one process of drawing. Multipledrawing processes create a very high level of drafting waves. Additionally, these fibres normally have to be run atspeeds below 400 m/min.

Synthetic fibres with high fibre-to-fibre cohesion require higher drafting forces, create more heat and in generalhave to run at slower speed, in the range of 400 to 500 m/min.The fibre finish on some synthetic fibres can create a finish build up on the machine, in the coiler tube and on thecoiler plate. Care has to be taken to keep the machine clean.Some bulky synthetic fibres need special components to run well. Check with the business unit if this is aproblem.

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2.3. Number of drawing processes

The number of drawing processes is normally established by the technological requirements because the cost ofdrawing is relatively low. However, there is always pressure to reduce processing steps to remain competitive.It is well established that the card produces a sliver containing both leading and trailing hooks that have to beeliminated prior to high draft ring spinning. This is normally done by using two passages of drawing.

2.3.1. Single process drawing

Single process drawing can be used where the spinning process is not sensitive to fibre hooks or poor fibreorientation. These include:The spinning of coarse counts from blends containing very short fibres such as comber noil, regenerated fibres or

gin motes. An additional drawing process is not used with this type of material because it can create problems ofdrafting waves and reduced sliver cohesion.Rotor spinning of coarse and some medium count yarns. Fibre hooks and fibre orientation do not greatly affectthe spinning process but there will be a loss of strength by using only one process of drawing. This is not aproblem for many applications.Coarse counts spun from synthetic fibres. Some carpet and upholstery yarns are produced on both ring and rotorspinning systems.

2.3.2. Two process drawing

The conventional short staple process, for “carded” yarns of cotton, man made fibres and intimate blends,includes two drawing processes.The primary reasons for two processes are:To reduce the number of fibre hooks in the sl iver,Supply roving, with the majority of hooks trailing, to the ring spinning,To improve the degree of fibre orientation in the sliver,To enable blending through doubling to improve yarn consistency,To gradually reduce the sliver weight from the card sliver to that needed by the roving or spinning machines.

2.3.3. Drawing for combed yarns

In the modern combed yarn spinning, there are three drawing operations:First passage of preparation drawing is used to draw card sliver and produce sliver that can be wound onto lapsfor the comber.The second drawing operation occurs at the comber to reduce the sliver weight. Relatively high drafts are neededat this stage and the drafting zone is very robust. The drafting system is normally a 3 over 5 roller arrangement toclearly separate the fibre control function of the break draft zone and the main draft zone.The third drawing operation is performed on the finisher Drawframe.The comber eliminates most of the fibre hooks, hence the remaining functions of the Drawframe are to produce avery uniform sliver of the required weight. This “one process drawing” after combing has been made possible bythe successful use of the RSB autoleveller Drawframe.

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2.3.4. Three process drawing for Drawframe blends

When blending different fibres at the Drawframe, multiple processes have to be performed to produce ahomogeneous finished sliver. This is usually necessary for ring spinning.(An exception is in rotor spinning in which the yarn formation steps separate the fibres and reassemble them inthe rotor to produce a well-blended yarn. In some rotor spinning plants only two drawing processes are used).

2.3.5. Three process drawing for air jet and Vortex spinning

Three processes of drawing are normally used to prepare sliver for MJS and MVS.The spinning machine drafts directly from sliver with drafts over 150. The fibres in the sliver have to beindividualized and very well oriented. With three processes of drawing, the spinning machine functions more

efficiently.The machines need light sliver weights to be able to spin medium and fine yarn counts. Slivers in the range of 35grains/yard are not unusual. Three drawing steps are helpful in converting relatively heavy card sliver into lightfinisher drawing sliver.The processing of combed cotton for MVS is a challenge because spinning results are good with only oneprocess of autoleveller drawing after the comber. This requires drafts much higher than normal range.

2.4. Sliver quality

As frequently mentioned throughout the chapter on Settings, the sliver quality is of primary importance. The sliverquality is normally judged by consideration of the Test Lab Data produced under controlled conditions.

2.4.1. Sliver weight

The weight of the sliver is usually measured in g/m or grains/yard. Obviously, the shorter the length of theindividual samples, the more the variation is revealed. For example, it is not recommended to reel long lengths ofsliver to check the autoleveller function.The following checking procedures are suggested.Delivered sliver weight of a machine - 5 x 10 yd (m).( Not consecutive lengths.)

Machine to machine sliver weight control – 5 x 10 yd (m) lengths from each machine.“Sliver Test” for levelling intensity…3 x 10 yd (m).Care has to be taken when manually preparing and cutting lengths of sliver. The sliver is easily stretched and ifdifferent operators perform the task there can be manual errors introduced.When a reel is used, care should be taken to prevent sliver tension variations that could cause uncontrolled sliverstretch.

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2.4.2. Sliver evenness CV%

The evenness is normally measured by passing the sliver through a measuring head that records a capacitivesignal measuring the mass of every 12 mm of sliver length. The values are represented in a continuous chart thatshows the variation of the sliver above and below a mean value. This chart is called the “Diagram” in this text.

The data is used to calculate the mathematical value of mass variation known as the Coefficient of Variation(CV%). The lower the CV%, the more uniform is the sliver. Additionally, a Spectrogram is produced that shows the periodic occurrences of variations.

It is normal for customers to request the lowest possible sliver CV%. To do this, the draft distribution has tooptimal and the roll settings close. These tight roller settings tend to:Over control the sliver and break the longest fibres,Reduce the yarn strength,

Increase the ends down rate in spinning.Create small “spikes” visible in the evenness diagram that causeIncreased thick places in the yarn.

25201510

010152025

Evenness diagram of a sliver with a low CV% but with spikes in the diagram

0 25 50 75 100 125 150 175 200

The ultimate judgment of the best CV% can be made only by considering the Diagram, the Spectrogram, theprocessing performance at roving and spinning and the yarn quality. Unfortunately a considerable length of timeis needed to perform these extensive evaluations; hence, the customer should be encouraged to assist.

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2.4.3. Effects of close roller settings

Effect of Drawframe roller spacing on yarn qualityNe 30/1 – 100% combed cotton ring yarn. (41 mm staple)

Too tight(lowest CV% 2.7%)

Optimized setting(CV 3.0%)

Roller spacing (HVD/VVD) 40 / 46 42 / 47

Single end strength 420 g 412 g

Strength variation -Vo 7.8% 6.2%

Single end elongation 6.5% 6.5%

Elongation variation -Vb 2.4% 1.9%

Uster CV % 12.2 11.7

Thins 0 1

Thicks 16 10

Neps 11 10

Classimat minors 80 28

Majors and long thicks 22 2

ITT quality index(higher is better)

137 146

Recommendation – In many cases the best settings are found to be:

Roller distances for lowest CV% but with the main draft zone opened up by 1 - 2 mm, and the break draft zoneopened 2 – 4 mm.

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2.4.4. Spectrogram

The spectrogram is extremely important in judging the sliver quality in that the periodic mechanical faults and thesliver irregularity waves can be seen. Additionally, if the levelling action point is not correctly optimized, a hump inthe spectrogram will be visible somewhere between 35 cm and 50 cm.

Spectrogram of a typical mechanical defect peak

Spectrogram of a typical break draft wave

Spectrogram of a LAP setting wave

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2.4.5. Sliver characteristics

The appearance of sliver can indicate the quality, and is an important element in judging how well a machine isperforming.

2.4.5.1. Appearance of coiled sliver

When the can is full and doffed the following points should be observed:The sliver should not be “scuffed” from over filling. This leads to matted fibres that are difficult to draft insubsequent processes. DO NOT OVERFILL the cans.If the sliver is folded during the coiling action the tension is too low.Fibre tags on the surface of the sliver usually means that the coiler tube or coiler plate has a rough place that

needs to be repaired or replaced.Trash accumulations in the top coils, sometimes referred to as “mice”, are due to trash collecting in the coiler tubeduring running and being released as the coiler slows down at a stop. The coiling tension should be reducedslightly to enable the sliver to have a more complete contact with the coiler tube.

2.5. Sliver cohesion

If the sliver has low strength, the trumpet, calender roller pressure and coiler tube inside diameter should bechecked to see if they are correct for the sliver weight and material being processed.

With combed cotton, the strength of the drawn sliver is influenced by the piecing produced at the comber. Manytimes the optically best piecing seen in the combed web is too delicate for the subsequent drawing steps. It issuggested that heavier overlaps at combing produce a stronger sliver. The associated mass increase can besubsequently corrected by the levelling action of the autoleveller Drawframe.

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3. Machine Elements

3.1. Sliver feed

The running performance of the material in the creel is critical to the Drawframe efficiency and the delivered sliverquality. Operator practice and machine set-up have to be carefully monitored.

3.1.1. Creel height

Creel height should be sufficient to allow a sliver balloon to develop between the top of the material in the canand the creel guide. A minimum clearance of 500 mm is preferred. Avoid “dragging” the slivers across the top of the cans. Sliver stretching occurs which is very undesirable. Additionally, slivers dragging over the can edge disturbs the sliver and creates defects which will be seen in theyarn.

3.1.2. Block creeling

If the length of sliver in the cans in the Drawframe creel is consistent, block creeling is frequently preferred.Drawframe efficiency is increased because of reduced stops due to sliver run-out.

With no sliver splices due to creel can changes, the delivered sliver is of a higher quality and creates fewer stopsin the downstream processes.Bad splicings in the creel can create chokes at the condenser, or undrafted pieces in the delivered sliver thatcannot be drafted in ring, air-jet or Vortex spinning.Removal of the creel splicings after drafting produces the best sliver quality. With block creeling, the creel sliversplicings are run through the Drawframe into the can and then removed from the top of the can.

3.1.2.1. Random creeling

When a plant selects to random creel, the creel sliver splice is not normally removed. Therefore the operator hasto be taught how to make a splice, which will be sufficiently strong to be transported through the creel, but be softenough to be drafted out in the draft zone.

Avoid damaging sliver by reaching down the side of the can to find the sliver tail when it is to be spliced to thesliver in the following can.

If a sliver end is laid into an adjacent sliver and that is then used to pull the sliver end through the machine, caremust be taken to ensure that the slivers are correctly arranged in the rake.Some operators are required to pull the new sliver over the creel through the rake and the fold the end into anadjacent sliver. This system can work well as long as the sliver and the end are not compacted and difficult to

draft.

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3.1.3. Sliver splicing technique

Prepare the sliver ends to be spliced by removing a Vee shaped portion about 2 to3 inches long.Overlap the Vee portions of each sliver to form a relatively uniform joint.Work the fibres in the joint by lightly pulling sideways to create an integrated splice.Squeeze the joint together and roll slightly between the palms of the hands to develop some sliver cohesion.Do not roll and twist the splice, or wet the palms of your hands to make the slivers stick together.The splice should be draftable and not cause a hard slub.

1. V-Shape Preparation 2. Overlap Sliver 3. Good SplicingBad Splicing

3.1.4. Static creel

In the static creel the slivers have to be pulled from the cans over the guides and into the Drawframe. It is veryimportant to minimize drag angles over bars and guides. It is particularly bad when the sliver is pulled through aring or over a bar and there is an angle of wrap of almost 180 degrees. Position the cans to permit the sliver pathto be as direct as possible. Remove all rough places that cause slivers to hang. Avoid placing cans so that thesliver balloons become entangled.

3.1.4.1. Power creel

The power creel is provided to reduce the tension forces in the sliver. The sliver is pulled up from the can by alifting roll and is then pulled to the feed roll. The drive to the lifting rolls can be varied so that there is only a slightsliver tension and no overfeed. To find the preferred tension, reduce the tension in the creel until the sliver isslightly overfed and then increase the tension by one small step. If the speed of the machine is changed or thematerial is changed, it is common to adjust the creel tension.

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3.1.5. Sliver in-feed and jockey rolls

The jockey rolls driven by the In-feed rolls feed slivers to the Drawframe. Normally there are two slivers undereach jockey roll. If a sliver is missing the metal jockey roll should touch the in-feed roll and activate the stopmotion. The jockey rolls must be free to move. There should be 1.0 mm clearance between each stop pin and the jockey rolls. When roll clearers are provided for the sliver in-feed it is important that they be kept clean.

Adjustment of Jockey Roll

3.1.5.1. Sliver tension

It is important that the sliver tension should as low as possible but it should control the sliver movement.Reduce tension until slivers are loose and then increase the tension by one step.Check that slivers do not roll and cross as they move through the machine.Slivers should not be stretched.

3.1.6. Sliver feed to the scanning rollers

It is essential that sliver funnel and the scanning rolls of the auto leveller are very carefully set. An incorrectsetting can cause cutting of the fibres, sliver tags and highly compressed sliver fringes that are not subsequentlydrafted.The funnel should be correctly located and be 0.5 - 1 mm from the scanning rolls.The funnel must be centred relative to the scanning roll groove.The tongue and groove components must not make contact with each other

The sensing scanning roll must not touch the funnelThe clearances between the scanning rolls should be checked at ¼ turn positions to be sure that they arecorrectly aligned.

Clearances should be checked above and below the tongue as well as between the tongue and inside of thegrooved roll.Sharp edges of the scanning rolls can cause cutting of fibres. This shows up as an increase in short fibre contentafter drawing. Additionally synthetic fibres can be fused. The sharp edges should be polished away by using fine“Scotch Bright” or similar polishing material.

The pressure on the scanning roll should be carefully adjusted to suit the processing speed and the materialbeing drawn.

If there is scanning roll vibration the pressure should be increased incrementally.

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For bulky coarse synthetic fibres it is sometimes necessary to increase the pressureFor polyester the pressure is usually light.

Check that the scanning roll assembly screws do not touch the table. This is a problem if a change is made tosmaller scanning rolls and using the same length screws.Clean the funnel. There should be no contamination, burrs or rough places.

Funnel and scanning rolls

3.2. Scanning rollers to drafting system

3.2.1. Sliver tension

The sliver tension must be carefully adjusted to avoid sliver stretching but to be sufficient to cause the slivers tospread after the high compression of the scanning rolls.High tension will cause irregular stretch that cannot be corrected by the autoleveller.With combed cotton the piecings can be disturbed and the autoleveller will not function correctly.Reduce the tension until the slivers are slightly loose and then increase the tension one step.The sliver should not drag on the table.

3.2.2. Sliver spreading

When the slivers leave the scanning rolls the material is very compacted and has to spread to a “side by side”condition prior to entering the drafting system. Slivers must not roll and cross each other.The sliver guide bars L1, L2, L3, and L4 must be set so that the slivers are:

in the centre, uniformly next to each other, without gaps between the slivers, no slivers crossing, without rolling and twisting.

In addition to the sliver tension, the relative heights of the sliver guide bars influence the spreading action. Theconvex shape of the guide bars helps in the spreading action.

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Initially set the bar heights with L1 in the high position, L4 below the back roll of the drafting system, L2 and L3 asshown in the diagram.

If the spreading is excessive and the slivers are moved apart then lower L3 or raise L2The sliver path must be as that shown in the diagram, otherwise the correct levelling and drafting functions will bedisturbed.

3.3. Drafting

Sliver path through the Drafting System

The drafting system is basically 3 over 3 with an additional “Deflection” roll (7) on the delivery roll to direct the

sliver toward the coiler. The top rolls are numbered (1, 2, 3) and corresponding bottom rolls are, - back roll (4),middle roll (5) and delivery roll (6). There is a pressure bar (8) located between the top rolls 2 and 3 to helpcontrol the fibres in the main draft zone.The fundamental settings of the drafting system are the roll distances and the draft distribution. Each greatlyinfluences the quality of the delivered sliver.

3.3.1. Critical factors affecting the drafting action

roll settings,

draft distribution, roll pressure, speed, top roll cot condition removal of dust, fly and clearer waste.

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3.3.2. Roll setting

Drafting roll distances have to be set as close as practicable:To control the short and floating fibres,Not so close as to break the longest fibres, norNot so close as create high drafting forces and over control.

The roll setting has to be optimized according to: Staple length, ( 2.5% on HVI or AFIS and 1.0% on the Peyer AL-101) fibre orientation, sliver weight fibre crimp, bulk and cohesion.

The number of fibre hooks are decreased and the degree of fibre orientation is increased each drawing process.

Therefore, it is necessary to set the roll spacing with this in mind.

3.3.2.1. Setting tip

From the practical setting perspective, the main draft rolls should be set first, followed by the setting of the breakdraft zone. Any change of the distance between rolls (5) and (6) automatically changes the distances betweenrolls (4) and (5). Consequently, a change of setting of the main draft zone must be followed by an adjustment ofthe break draft rolls.The converse is not so. A change of the distance of the break draft zone does not change the positions of rolls (5)and (6).

3.3.2.2. The main draft zone roll – setting (H V D)

The main draft rolls have an actual minimum setting of 35.5 mm, which is used for all fibres with staplelength shorter than 27 mm.

For fibres of staple length 27 mm or longer, the rolls are normally set at 8 ….10 mm over the 2.5% lengthvalue.

3.3.2.3. Break draft zone - roll setting (V V D)

The break draft roll setting is dependent upon the condition of the supplied sliver. The maximum andaverage staple lengths, the degree of fibre orientation, the fibre hooks, the drafting resistance, and the draftdistribution all have an influence on how close the rolls can be set. A simple test for the break draftresistance is to use a 1 or 2 mm feeler gauge and push it between the first and second rolls into the slivers.The fibres should yield but with resistance. The rolls are too close if the slivers do not allow the feeler to bepressed through.

Closest roll setting is 36 mm Common roll settings range from 10…15 mm over the 2.5% staple length.

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3.3.3. Draft distribution

The total draft is established by the total mass of the input material and the mass of the output sliver. The calculation is: Total draft (V) = Input mass

Delivered mass

The total draft is performed in two stages. The first step is the “Break Draft” (V V), which prepares the slivers forthe “Main Draft” (V H)

3.3.3.1. Break draft zone - Draft (V V )

The function of the break draft in the Drawframe is to pre tension the slivers and remove the sliver crimp so that

the fibres presented to the main draft zone are controlled. The normal range is 1.16 to 1.41, but with polyester forsewing thread and crimped acrylic the break draft can be up to 1.70. The break draft in the first drawing passageis usually higher than that of the second passage because the card sliver has a lower level of fibre orientation.The evenness tester diagram and spectrogram should be used as a guide in setting the draft. The followingobservations can be made:

Breaker drawing requires higher break draft than subsequent drawing processes. Warning: Roll settings that are too close will result in over control, which can be seen as “spikes” in the

evenness diagram. These spikes cause thick and thin places in the yarn. Finisher drawing requires more open settings and a lower break draft. Man made fibres require higher break drafts than cotton. Finer fibres, cotton or man made, require higher break draft than coarser fibres. When the total draft has to be relatively high (7 to 10) the break draft has to be increased to keep the

main draft in the desirable range. When processing short fibres the break draft should be low.

3.3.3.2. Main draft zone – Draft (HV)

The main draft is established by the total draft and the break draft. The total draft is set by the overall processingsystem and usually has to be accepted. However, for high quality products, it is recommended to limit theDrawframe draft to less than eight (8), which means the main draft will be between 3.5 and 5.5.

The best main draft settings are dependent upon the materials being processed, and the following

points generally apply; Comber noil HV – 3.8, short carded cotton HV – 4.75, carded cotton HV – 5.2, combed cotton HV – 6.1, Egyptian combed cotton HV – 7.1, cotton /MMF Blends HV – 6.2, viscose HV – 6.3, acrylic (crimped) HV – 5.2, polyester (crimped) HV – 6.0, polyester (sewing thread) HV – 3.7, polypropylene (…..den) HV – 6.1

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3.3.3.3. Examples of roll and draft settings

Roll settings and draft recommendations

Material

Max.staplelengthmm

Processdrawing

Doubling Feedktex

TotaldraftV

BreakdraftVV

Maindraft rollsettingHVD

Breakdraft rollsettingVVD

100% comber noil 23 I RSB 4 6 4,9 1.28 35,5 37

I SB 4-6 4,5 - 6 4-6 1.16 37 37-38Intimate blend65% CO /35% comber noilCO waste

38II RSB-D 30 4-6 4,5-6 4-6

1,16(1,057)

37 37-38

I SB 6 5 5-5,5 1,28 37,5 39CO carded, withhigh amount of

short fibres

34

II RSB-D 30 6 5 5-5,5 1,16 37,5 42

I SB 6-8 4,3 6-81,281,16

384347

Peru Tanguiscarded(_)= 8 doubling

spin-staple

approx.34...39

II RSB-D 30 6 (8) 4,3 6 (8) (1,28) 38 (44)

COCombed 1 1/16"

36 I RSB-D 30 6 4,2 7,1 1,16 38 45

38-39 I RSB-D 30 8 5,3 8 1,16 40 52Egyptian CO,combedSL 2,5% = 34,6 mmSL 50% = 18,5 mm

43 I RSB-D 30 8 4,2 8,3 1,16 44 52

I/II SB 8 5 8 1,41 /1,28 43 4850% cottoncombed50% PES1,7 dtex/ 40 mm

38/39 III RSB-D 30 8 5 8 1,28-1,41 44 50

I/II SB 8 4 8 1,41 42 4650% cotton1 1/16"carded50% modal1,3 dtex/ 38 mm

38III RSB-D 30 8 4 8 1,28 41 48

I SB 8 4,9 9 1,41 43 46CV (viscose)1,3/40 mm 38

II RSB-D 30 8 4,7 8,3 1,28 44 48

I SB 6 4,6 6,8 1,70 44 48PAC1,3 dtex/ 40 mmcrimped

38II RSB-D 30 6 4 6,7 1,28 44 50

I SB 8 4,8 8,4 1,41 43 50PES

1,9 dtex/ 38 mmcrimped

38II RSB-D 30 8 4,6 8 1,28 43 50

I SB 6 3,8 6,4 1,70 44 50Sewing threadPES1,3 dtex/ 38 mm

38II RSB-D 30 6 3,6 6,4 1,70 44 48

I SB 6 5,0 6 1,70 58 65PAC3,3 dtex/ 60 mm,crimped, dyed

spinstaple

approx.53/54

II RSB-D 30 6 5,0 8 1,41 58 65

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3.3.4. Roll pressure

The top rolls are pressure - loaded against the bottom rolls to grip the fibres between the rolls and to increase thefibre bundle pressure in the drafting zone. The pressure should not be excessive, but has to be sufficient tomaintain a consistent drafting action.

The following points should be noted:Rolls 1, 2, and 3 are pre set to 320 N,

Deflection roll 7 is preset to 200 N,For conditions of high drafting forces, such as, low draft ranges, heavy sliver weights or fibres that have a strongdrafting resistance the top roll pressure has to be increased to:

Top rolls 1 and 2 to 440 N,Top roll 3 to 320 N,Deflection roll 7 remains at 200N.

When the top roll pressure is increased the effective nip zone is extended reducing the distances between the nippoints. To compensate for this, it may be necessary to increase the draft roll settings by 1 or 2 mm.Increasing the roll pressure increases the temperature or the rolls,Lifetime of top rolls is reduced,Top roll deformation will occur if roll pressure is left on when the machine stopsWith the pneumatic top roll loading system, the pressure is automatically released. This prevents the formation offlat spots on the cots.

Pressure on Drafting System

3.3.5. Speed

Speeds of the Drawframe have been progressively increased. In most cases the maximum speed of theDrawframe is limited by:

The running condition, which is fibre dependent, or The sliver quality that can deteriorate as the speed exceeds optimal levels. Normally, the Drawframes are run at speeds below the maximum rate because the cost of drawing is a

relatively small component of the overall spinning costs.

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3.3.5.1. Effects of excessive speed

Increased top roll laps, Roll temperatures exceed the tolerance of some man made fibres, Increased machine stops and reduced efficiency, Deterioration in sliver quality, Reduced lifetime of the cots, Overheating of the bearings, Guide to maximum Drawframe speeds.

The following chart is taken from the sales documentation and represents the delivery speed expectancies ofcurrent Drawframes. It should be emphasized that speeds approaching the maximum speeds can only beattained when all conditions are optimal.

3.3.6. Cot condition

Top roll cot condition is very important in obtaining an efficient performance of a Drawframe and maintaining anacceptable quality level. The followings should be observed:Top roll cots are selected to produce good quality sliver and to minimize roll laps.Warning: Fibre laps should not be “cut” from the cots. The cots can be nicked and cut which leads to runningproblems and loss of quality.

Cots can be provided with spiral grooves to reduce the tendency to wrap.

The table shows cots supplied as standard on Rieter Drawframes.

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Material

Hardness

AccotexJ490-A grey

83 shore

Day WW 121black

78 shore

Accotex 714M green

80 shore

Peach

73 shore

Combed cotton XXX

Carded cotton XXX XX

Cotton/PES blends XXX XX

Man made fibres XXX

Polyester fibres XXX

PES/cotton for MJS XXX

The grey cot J 490-A is wear resistant, pressure resistant and easy to buff.The black cot WW 121 is used for fibres that have a tendency to lap. It is frequently used where high quality isrequired and on the back top roll.The green cot Accotex 714 M is used for processing 100% polyester to reduce static build-up.Damaged cots should be replaced. They normally cannot be buffed.Worn cots need periodic buffing to remove small defects. Normal time between buffing operations isapproximately 500 hours.

New cots are normally pre-treated with UV light to reduce the lapping tendency. After buffing an UV irradiation ora chemical treatment is recommended to smooth the surface.

The minimum diameter of the top rolls is 36 mm. They should not be buffed below this limit.Top roll clearers should be used only if required to reduce top roll laps.Clearers increase the temperature of the drafting system and reduce the lifetime of the cots.

3.3.7. Dust, fly and waste removal

The drafting action causes dust and fly to be released from the fibres. The airborne waste must be removed or itaccumulates and eventually returns into the sliver as contamination. The integrated suction system removes dustand fly from the sliver:

At the jockey rolls, the scanning rolls, above the drafting system, below the drafting system.

The integrated waste system is equipped with a pressure sensitive switch, which controls a wiper over the filterscreen, to release waste accumulations.

The Drawframe should be kept as clean as possible and periodic manual cleaning is necessary. The cleaningcycle depends upon the cleanliness of the material being processed.

Bottom roll clearers have to be manually cleaned.

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Waste accumulated in the Drawframe can be released and gathered into the sliver. This waste creates eithersubsequent machine stops or quality defects.

Suction System

3.3.8. Sliver formation

The fibres emerge from the drafting system as a delicate, thin web that is collected and then compacted into asliver. The degree of fibre disturbance has to be kept to a minimal level so as to not disturb the fibre assembly.

3.3.9. Web funnel insert

The sliver funnel directs the fibres into the funnel insert which creates a loosely compacted sliver. This sliver thenpasses to the condenser (trumpet) and associated calender rolls.The inside diameter of the insert depends upon the bulkiness of the material.

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The following table is Rieter’s recommendation taken from the Machine Manual.

Recommendations for Web Funnel Inserts(Inside diameter in mm)

PES PES CV CV PAC PACCOCard

COComb

C/PCard

C/PComb

P/CVC/Pac

Material sliver weight

Grains/Yard

NmKtex P

E S ( C O - T y p e

1 . 3 . . . 1 . 6

d t e x / 3 8 …

4 0 m m

M o d i f i e d

P E S ,

P E S ( w o o l - t y p e )

b u l k y t y p

e ,

m i c r o f i b r e < 1 . 3

d t e x ,

>

>

C V ( C O - T y p e ) , C V M o d a l

1 . 3 … 1 . 6

d t s x / 3 8 … 4

0 m m

M i c r o f i b

r e < 1 . 3

d t e x ,

N o r m a l f i b r e s > 2 d t e x / > 4 0 m m

P A C ( C O

- T y p e )

1 . 3 … 1 . 6

d t e x / 3 8 … 4

0 m m

H i g h b u l k y t y p e ,

M i c r o f i b r e <

1 . 3

d t e x ,

N o r m a l f i b r e s > 2 d t e x /

> 4 0 m m

C O a n d

C O - c o t t o

n w a s t e b l e n d s

C O - b

l e n

d s w i t h P E S ( C O - T y p e )

5 0 / 5 0 ,

P E S b l e n d s w i t h C V ( V i s c o s e ) ,

C O - b

l e n

d s w i t h P A C ( C O - T y p e )

95 / 83

0.15 / 0.176.7 / 5.9

11.5 11.5 11.5 11.5 11.5 11.5 11.5 10 11.510 /11.5

11.5

78 / 740.18 / 0.195.55 / 5.25

10 /11.5

11.510 /11.5

11.5 11.5 11.510 /11.5

8 / 1010 /11.5

10 /11.5

10 /11.5

70 / 670.20 / 0.215.0 / 4.75

1010 /11.5

10 /11.5

10 /11.5

10 /11.5

11.58 /10

8 10 10 10

64 / 610.22 / 0.234.55…4.35

8 108 /10

10 1010 /11.5

8 8 8 / 10 8 / 10 8 / 10

59/ 560.24…0.254.15…4.0

8 8 / 10 8 8 / 10 8 / 10 10 8 8 8 8 8

54 / 520.26…0.273.85…3.7

7/8 8 8 8 8 8 / 10 8 8 7 / 8 8 8

50 / 480.28…0.293.55…3.45

7 8 7 / 8 8 8 8 / 10 8 7 7 / 8 7 / 8 7 / 8

47 / 440.30…0.323.35…3.15

6 7 / 8 6 / 7 7/ 8 7 / 8 8 6 / 7 6 7 7 7

42 / 40

0.33…0.35

3.0..2.85 6 7 6 / 7 7 6 / 7 7 / 8 6 6 6 6 7

39 / 350.36…0.402.75…2.5

5 6 5 / 6 6 / 7 5 / 6 6 5 5 5

34 / 180.41…0.802.45…1.25

5 / (4) 6 (4) 6 5 5 / 6 (4) / 5 (4) / 5 5

PES= Polyester, CV = Viscose / Rayon, PAC = Acrylic, CO = Cotton

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3.3.8. Condenser (Trumpet)

The condenser helps to form the sliver and removes the air from the fibre mass before the material passesthrough the calender rolls. The degree of condensing influences the sliver cohesion, which has to be sufficient forsliver handling at the next processing stage. However, if the sliver cohesion is too great it can have a negativeimpact upon subsequent drafting.

The condenser hole diameter depends upon the sliver weight and bulk.For combed cotton the hole diameter may be up to 2 mm smaller than for carded cotton.For synthetic fibres the hole diameter may be up to 2 mm larger than for carded cotton.

Recommendations for condensers (Trumpets)(Inside diameter in mm)

PES PES CV CV PAC PAC COCard COComb C/PCard C/PComb P/CVC/Pac

Material sliver weight

Grains/

Yard

Nm

Ktex

P E S ( C O - T y p e

1 . 3 . . .

1 . 6

d t e x / 3 8 …

4 0 m m

M o d i f i e d P E S ,

P E S ( w o o l - t y p e )

b u l k y t y p e ,

m i c r o f i b r e < 1 . 3

d t e x ,

>

>

C V ( C O - T y p e ) , C V M o d a l

1 . 3 … 1 . 6

d t s x / 3 8 … 4

0 m m

M i c r o f i b r e < 1 . 3

d t e x ,

N o r m a l f i b r e s > 2 d t e x / > 4 0 m m

P A C ( C O - T y p e )

1 . 3 … 1 . 6

d t e x / 3 8 … 4

0 m m

H i g h b u l k y t y p e ,

M i c r o f i b r e < 1 . 3

d t e x ,

N o r m a l f i b r e s > 2 d t e x / > 4 0

m m

C O a n d

C O - c o t t o n w a s t e b l e n d s

C O - b

l e n d s w i t h P E S ( C O - T y p e )

5 0 / 5 0 ,

P E S b l e n d s w i t h C V ( V i s c o s e ) ,

C O - b

l e n d s w i t h P A C ( C O - T y p e )

95 / 83

0.15 / 0.176.7 / 5.9

4.6 /5.0

4.6 /5.5 (6)

4.6 /5.0

4.6 /5.5

4.6 /5.0

5.0 /6.0

(6.5)

4.6 /5.0

4.6 /5.0

4.6 /5.0

4.6 /5.0

4.6 /5.0

78 / 740.18 / 0.195.55 / 5.25

4.2 /4.6

4.6 /5.0

4.2 /4.6

4.2 /5.0

4.6 /5.0

4.6 /5.5

4.2 /4.6

4.2 /4.6

4.2 /4.6

4.2 /4.6

4.2 /4.6

70 / 670.20 / 0.215.0 / 4.75

4.24.2 /4.6

3.8 /4.2

4.2 /4.6

4.2 /4.6

4.2 /5.0

3.8 /4.2

3.8 /4.2

3.8 /4.2

3.8 /4.2

4.2 /4.6

64 / 610.22 / 0.234.55…4.35

3.8 /4.2

4.2 /4.6

3.8 /4.2

4.2 /4.6

3.8 /4.2

4.2 /4.6

3.8 /4.2

3.8 /4.2

3.8 3.83.8 /4.2

59/ 560.24…0.254.15…4.0

3.5 /3.8

3.8 /4.2

3.5 /3.8

3.8 /4.2

3.8 /4.2

3.8 /4.2

3.5 /3.8

3.5 /3.8

3.5 /3.8

3.5 /3.8

3.5 /3.8

54 / 52

0.26…0.27

3.85…3.7

3.5 /

3.8

3.8 /

4.23.5

3.8 /

4.2

3.5 /

3.8

3.8 /

4.2

3.2 /

3 5

3.3 /

3.53.5 3.5 3.5

50 / 480.28…0.293.55…3.45

3.2 /3.5

3.5 /3.8

3.2 /3.5

3.5 /3.8

3.5 /3.8

3.5 /3.8

3.2 /3.5

3.33.2 /3.5

3.2 /3.5

3.5

47 / 440.30…0.323.35…3.15

3.2 /3.5

3.5 /3.8

3.0 /3.2

3.5 /3.8

3.2 /3.5

3.5 /3.8

3.0 /3.2

2.8 /3.0

3.23.0 /3.2

3.2 /3.5

42 / 400.33…0.353.0..2.85

3.0 /3.2

3.2 /3.5

2.8 /3.0

3.2 /3.5

3.2 /3.5

3.2 /3.5

2.8 /3.0

2.5 /2.8

3.0 /3.2

2.8 /3.0

3.2

39 / 350.36…0.402.75…2.5

2.5 /2.8

2.8 /3.0

2.5 /2.8

2.8 /3.0

3.0 /3.2

-- 2.8 2.52.5 /2.8

2.5 /2.8

--

34 / 180.41…0.802.45…1.25

2.2 /2.5

--2.2 /2.5

--2.5 /2.8

--2.5 /2.8

2.2 /2.5

2.2 /2.5

2.2 /2.5

--

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3.3.9. Tension draft between front rolls and calender rolls

The tension draft between the front rolls and the calender rolls, (delivery rolls) will affect the running performanceand the sliver quality. The tension has to be sufficient to gather the web and pull the sliver through the condenserin a controlled manner. However, if the tension is too high the sliver uniformity will deteriorate and the sliver UsterCV % can be 0.5 % higher than it should be. As a guide, the following are tension ranges frequently used fordifferent materials:

Carded Cotton 1.01 to 1.02, Combed Cotton 1.00 to 1.01, Polyester/Cotton 0.99 to 1.0, 100 % Synthetics 0.98 to 1.00

3.3.10. Calender roll pressure

With the correct pressure on the calender rolls the sliver passes directly into the centre of the coiler tube. Thebasic calender roll pressure is 320 N obtained with a spring length of 62 mm. For sliver of different weights,bulkiness and processing at different speeds the pressure may need to be adjusted for a smooth runningcondition and a correct operation of the Rieter Sliver Monitor.The following table shows the Calender Roll pressures obtained with different spring lengths:

Calender Roll Pressures

Pressure(N)

Spring Length(mm)

150 76

200 72

290 65

320 62

400 56

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3.4. Coiling

When coiling sliver into the can it is important to maintain:a smooth compacted sliver with low hairiness,fill the can in the correct manner andminimize dust / trash accumulations in the coiler tube.

3.4.1. Coiler tube

The form of the coiler tube has been developed to enable the sliver to move with minimal interference into thecan. The tube is normally made of stainless steel, which is wear resistant and suitable for most fibres. There are avery few exceptions in which the sliver is not compatible with the frictional characteristics of steel, and will not

freely slide through the tube. In this case it may be necessary to use a brass coiler tube.The coiler tube and plate have to be selected to suit the sliver weight and the diameter of the sliver can.

3.4.1.1. Coiler tube inside diameters

To obtain a smooth and compacted sliver the coiler tube should be as small as practicable. If the tube diameter istoo large for the sliver, the sliver will have a tendency to:

Be hairy, create difficulties during withdrawal from the can,

have a reduced sliver cohesion. detailed Rieter recommendations can be found in the machine manual.

3.4.2. Sliver deposit

Depending upon the sliver can size, the sliver is coiled either “over centre” in cans 225 to 600 mm diameter or“under centre” (some references use “onto the centre”) in cans 800 to 1000 mm diameter.

3.4.3. Coiler settings

To maintain good quality coiling of the sliver, the following points of the coiler have to be correctly set:Coiler speed depending upon material and sliver weight. The speed must not be excessive and stretch the sliver,nor too slow and lay the sliver unevenly in the can.Can location (eccentricity) to build a column diameter 10 mm smaller than the can’s inside diameter. This shouldbe checked when the can is 75 % full.Can table speed to adjust the coil spacing so that the sliver coils are side by side, not overlapping and not spacedapart.Length of sliver in a full can must not be excessive. An overfilled can creates problems of sliver disturbance andscuffing which leads to drafting problems at the subsequent processes.

The can condition has to be correct, damaged and out-of round cans cause many problems and a deterioration ofsliver quality.

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The cans must be of the required size and set relative to the coiler plate. The can spring length and pressuremust be correct for the material being processed. In addition, the can top to coiler bottom gap should be 30mm. If

it is more, the initial sliver will spill out of can. This leads to roving frame stoppage and sliver waste at the end ofeach can.

The coiling conditions have to be checked and, if necessary adjusted, with any change of:Sliver weight, - Material,Sliver bulkiness, - Delivery speedCan size.

3.4.3.1. Coiler speed

Check coiler speed

The coiler speed is too low. The sliver (1) is pulled to the outside of the coiler exit. This pushes the coils ontoeach other and the sliver tends to pull apart when being removed from the can.The coiler speed is correct. The sliver (2) leaves coiler plate at back of the kidney-shaped.The coiler speed is too high. The sliver is pulled to the inside of the coiler exit. The sliver is stretched, the coils willbe deformed and periodic draft faults may occur.

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Coiler speed correct3.4.3.1.1. Correct coiler speed

Coil diameter (A) is evenly round. Distance (a) between thecoils (A) remains uniform around the can.The form of the sliver column (2) is evenly round and 5 mm clear of the can side (1)

Coiler speed too low 3.4.3.1.2. Coiler speed too low

The coils are too wavy.The distance (a) between the coils (A) is relatively uniform.The Diameter of the sliver column (2) is too large and is equalto or greater than the inside diameter of the can (1).

Coiler speed to high3.4.3.1.3. Coiler speed too high

Sliver coils (A) are out of round and are not consistent. The

coils are drop shaped with the tip pointing toward the can insidewall (1)

The distance (a) between the coils varies from one coil toanother.

The sliver column (2) is out of round.

The sliver column (2) is too small and the clearance betweenthe column and the inside of the can is more than 5 mm.

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3.4.4. Sliver coils per can revolution

The sliver coils per layer is obtained by dividing the speed (rpm) of the coiler by the rotational speed of the cantable. With larger diameter cans the number of coils per layer increases to maintain optimal coiling and can filling.

nD = Relationship of coiler rpm to can table rpm

nD = coiler rpmcan table rpm

The following can be used as a guideline.

Coils per layer (over centre) (under centre)

Can

Dia. mm

225/

250

300 350 400 450 470 500 600 800 900 1000

nD 14.1 15.0 18.0 19.1 21.2 21.2 26.3 32.9 76.7 87.7 92.1

3.4.5. Can eccentricity

The outside diameter of the sliver column is primarily established by the relative positions of the centres of thecoiler and the can table. This distance is referred to as the eccentricity.If the can table is moved to reduce the eccentricity the sliver column will be reduced, and conversely the columnwill be increased if the table is moved to increase the eccentricity.

The setting of the can table eccentricity is normally not changed. However, it may be necessary to make a re-adjustment if there is a change to fibres of greatly different bulk characteristics, such as cotton to acrylic fibres.

3.5. Autolevelling

The introduction of the short-term, open-loop, electronic autoleveller on the RSB Drawframe has produced, worldwide, a very significantly improvement in yarn quality. In particular, yarn count variation, Uster evenness CV%,strength variation, Classimat minor defects and long thin places have been reduced.

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3.5.1. Autolevelling principle

All slivers entering the Drawframe pass through a bulk measuring head consisting of a pair of tongue and groovescanning rollers. Variations in fibre mass are detected as changes in thickness. Movements of the scanning rollerare transformed into voltages by a signal converter and forwarded to an electronic levelling processor.

RSB - Autoleveling System

The processor calculates the draft required to produce a levelled sliver. The correct values are fed to the servodrive that varies the speeds of the middle and back rolls. This changes the main draft to produce a levelled sliver.The timing of the levelling action is critically dependent upon the sliver speed, sliver path and staple length.The main motor drives the delivery rollers of the drafting system and the delivery speed remains constant. Theservo, through the planetary gearing, drives the middle and back rollers of the drafting system and all other sliverfeeding mechanisms.

3.5.2. Pre - Autolevelling setting

Very Important:Prior to adjusting the autoleveller, the Drawframe has to be correctly set with the autoleveller switched off. The

draft, roll settings, speeds, tension drafts and components have to be carefully optimized.

3.5.3. Autoleveller adjustments

The autoleveller should be set, adjusted and checked out as described in the machine manual. The followingpoints should be observed:

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Technology Handbook

3.5.3.1. Scanning rollers

The scanning rollers should be selected according to the amount of material being fed. The scanning rollerdistance, which corresponds to the cross-section of the total fed material, must be between 2.8 and 5.2 mm. Thefollowing table shows the recommended widths of the scanning rollers for various materials at different total sliverweights.

Scanning roller width recommendations

Input Sliver Weight

g/m 12 - 20 15 - 28 26 - 40 37 - 52

170 - 280 210 - 390 360 - 560 520 –730Material Width of scanning roller (mm)

Fine flexible fibres, i.e. combed cotton,rayon, and polyester (cotton type)

3 5 6.5 8

Cotton carded3 5 6.5 - 8 8 – 10

High crimped bulky fibres i.e. acrylic,polyester (wool type)

6.5 8 - 10 10

Synthetic of very high bulk6.5 8 - 10 10 – 12

Coarse polypropylene8 - 10 10 - 12

Grains/yd

The scanning rolls must not touch each otherwhen the pressure is on with no material in place,

The clearances between the tongue and grooveshould be 0.1 mm as shown in the diagram.

Clearances should be checked at several points

after partially turning the rollers.

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3.5.3.2. Sliver funnel Funnel Setting

The funnel should be clear of the scanning rollerswith no material present and the pressure on.

3.5.3.3. Scanning roller pressure

The scanning roller pressure has to be adjusted using the regulator and pressure gauge, according to thematerial being processed. An indication for the correct amount of pressure is the minimum deviation whenperforming the “add/remove” sliver test.Recommended scanning roller pressures are shown in the following chart.

Scanning roller pressures

Roller pressure daN (kg)

Delivery speed up to 500m/min Delivery speed 500 to 1000m/min

Material 100 120 140 160 180 100 120 140 160 180

Fine flexible fibres, i.e. combed cotton,rayon, and polyester (cotton type)

X XX X X XX X

Cotton carded XX X XX X

High crimped bulky fibres i.e. acrylic,polyester (wool type) X XX X XX

Synthetic of very high bulk XX X XX X

Coarse polypropylene XX X XX

Cotton / polyester XX X

XX - Standard application X - Optional when needed

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3.5.4. Desired target sliver weight

With the machine operational and the required number of slivers being fed, use the display menu 20.1 and select YES to calibrate the leveller. The machine must be running at the time of calibration, but the leveller must beturned OFF. The LED bar graph should zero itself (green) in the centre of the displayTurn leveller ON and run the machine to produce sufficient sliver for lab testing. Check sliver weight and UsterCV% and spectrogram.If the actual sliver weight is more than 1% different from the target sliver weight, change 20.2 in the menu andenter the actual sliver weight. Produce new sliver and check to see if it is acceptable. If not, continue to change20.2. Note: The leveller is not designed to correct weight differences of less than 1%.If the target weight cannot be reached because the scanning thickness is outside the thickness 2.8 to 5.2 mm, thepair of scanning rollers must be changed to the next appropriate size.

3.5.5. Levelling Action Point (LAP)

The levelling action point is in the main draft zone and is influenced by several factors that include: Tension of the sliver entering the drafting zone (VE) Main draft roll setting distance (HVD) Break draft (V V) Vertical setting of the sliver guides Delivery speed Fibre characteristics

The following diagram shows the factors influencing the levelling action point.

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3.5.5.1. Values of levelling action points

The levelling action point is set at menu 20.3 on the display.Note:Drawframes delivered before August 2000, were equipped with a B91 incremental switch with 90 pulsesper revolution.Newer machines and replacement encoders produce 88 pulses per revolution.

The following table lists the normal ranges of levelling action points (LAP) for some different materials:

Suggested value range of levelling action point 90 pulses 88 pulses

Material Break draft LAP values (mm) LAP values (mm)

Carded cotton 1.16 / 1.28 1005 - 1023 981 – 999

Combed cotton > 1 1/8” 1.16 1017 - 1035 993 – 1011

Combed cotton < 1 1/8” 1.16 1011 - 1029 987 - 1005

Synthetic fibres 1.28 / 1.41 1005 - 1023 981 - 999

To effectively arrive at the best (LAP), use the suggested value range, plus an intermediate value and producesliver samples of 100 m of each for testing. Evaluate the CV% and spectrogram and select the best. Then run twoadditional tests to choose the preferred setting.

Example of carded cotton. Suggested (LAP) range 1005 to 1023

- 12 mm + 12 mmTest 1: 1002, 1014, 1026

- 6 mm + 6 mmTest 2: 996, 1008

- 3mm + 3 mm

Starting guideline

1005

1008996

1011

1002 10261014

Test 3: 1005, 1011

From the first test, select the LAP which represents the best overall quality values. Spectrogram, CV-1m CVmUse this selection process to perform the second and third series of LAP tests, to find the correct Levelling ActionPoint.Note: Review the results and spectrograms before making a decision.

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3.5.6. Levelling intensity

The levelling intensity setting ensures that the leveller will correct the sliver weight if there is a major swing inmass of the in feed material. To check and set the levelling intensity a “Sliver Test” has to be performed. Thedelivered sliver produced from the normal feed is compared with slivers produced from feeds of normal plus onesliver and normal minus one sliver. The % deviation is then corrected by changing the levelling intensity at 20.3 inthe menu.

3.5.6.1. Sliver test

Before running the test, the menu 20.3 should be set with the levelling intensity at 99.0%. Also the “adaptationfibre type” should be entered.

Produce drawn sliver with the normal (n) number of doublings and take 3 samples of 10 m each. Weigh eachsample and determine the g/m or grains/yard. Calculate the overall average weight.Produce sliver with one less sliver (n–1) in the feed and calculate the overall average.Produce sliver with one additional sliver (n+1) in the feed and calculate the overall average.Use the chart in the machine manual, and follow the suggested procedures to find the percentage of “Undercompensation” or “Over compensation”. Adjust the levelling intensity value in 20.3 of the menu.Repeat the sliver test with the new levelling intensity value and correct if necessary.Exceptions: If a sliver test reveals an over compensation and an under compensation, of the levellingdevice then one of the following could apply:The wrong size scanning rollers are installed,The pressure of the scanning rollers is wrong for the application,The scanning roller is not able to move freely throughout its full range.

3.5.6.2. Sliver test protocol (example)

The following protocol is taken fromthe machine manual and can be

used as a guideline.

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3.5.7. Material correction factor (Menu 20.3.3).

This setting is also referred to as the “Adaptation fibre type” and is used to ensure that the system will functioneffectively at both running and jog speeds. Three, ten meter, samples should be produced at:Normal delivery speed andSlow speed by using the jog button (T)Compare the sliver weights.If the sliver produced at slow speed is heavier than that produced at normal speed, the material correction factorshould be increased.Re-check and continue to adjust until the difference in sliver weight is < 0.5%

3.5.8. Autoleveller set-up procedures at lot change

The chart on the next page shows a schematic sequence to effectively adjust the autoleveller at a lot change ofsliver weight or fibre type.

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Menu 20.1 (1)

Turn leveler >off

Set mechanical

draft

NW1 - NW2

Check sliver weight

in Lab, Adjust gears

if necessary

RSB-D30 Lot - change

Menu 20.2 (2)

Enter target sliver

weight

Menu 20.1 (2)

Automatic adaptationsliver weight >yes

Start machine with

slivers, w/o leveling

Raw material

change

Verify draft roller settings &

main / break draft.

Verify

Tension pullies

Verify

Scanning roller

Verify

Delivery speed

Stop machine

Menu 11.1 (2+3)

Set can fillingReset counter

Menu 20.3 (1)

LAP 1.Test

See recommen.chart

Menu 20.3 (2)

Leveling intensity

Recom. 99%

Menu 20.3 (3)

Adaptation fiber typeSee recommen.chart

Menu 20.1 (1)

Turn leveling >on

Start machine

Run 75 yards

check weight in Lab

Menu 20.2 (3)

Set actual sliver

weight

Run 75 yards,

check in Lab

Menu 20.2 (3)

If required, change

actual sliver weight

again

If "0"-point deviation

green LED, has drifted,

NW1 -NW2draft must be changed

Sliver weight

change

Yes NoYes No

Run machine withslivers, w/o leveling

Verify coiler speed

and can filling size

Stop machine

Run 75 yard samples,

in high and jog speed

Correct weight variation

with Menu 20.3 (3)

"Adaptation fiber type"

Perform sliver test

n-1, n, n+1

Tune in Menu 20.3 (2)

"Leveling intensity"

Perform LAP tests in

batches of 3 different

settings 1029,1011,993

Select LAP with best

CV%, run 3 additional

tests up/down 3mm inc.

RQM Menu 21.1

"Auto adapt.sliver weight"

>yes

Set A%, CV%, Spectrogram

limits

Set Draw frame

into production.

M e c h a n i c a l c h a n g e

P r o g r a m m i n g c h a n g e

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3.6. Online quality monitoring

The Drawframe can be supplied with either the Rieter Quality Monitor (RQM), or the Zellweger monitor (UQM).Both systems measure the consistency of the sliver as it passes from the drafting zone to the coiler. The RQMuses sensing roller to measure the mass of the sliver, whereas the UQM measures the pressure in the condenseras the sliver passes through it.

3.6.1. Rieter Quality Monitor (RQM).See machine manual.

3.6.2. Zellweger (UQM)See USTER manual

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4. Recommendations

4.1. Suggested settings for various spinning systems.

For each spinning system the drawing processes should be optimized to meet the requirements of the spinningequipment. The objectives of drawing are different for each system. For example: only one process drawing isused for the spinning of waste and regenerated fibres, and three drawing processes are needed for air jetspinning.

Carded ring spun yarns.

For the ring spinning drafting system to produce a good quality yarn, the fibre orientation is important. Additionally

the consideration of the “Fibre Hooks” created at the carding process is important.

Two drawing processes are needed between the card and the roving frame so that the majority of the remaininghooks are trailing as the roving enters the drafting zone.It is not recommended to use only one drawing process because the yarn quality will deteriorate and the spinningends down rate will increase.The recent introduction of drawing the card sliver at the card cannot replace a drawing process unless theamount of draft is sufficient to remove fibre hooks at that stage. Generally it is recognized that a draft of at leastthree (3:1) is needed to straighten the fibres and reduce the number of hooks.

4.2. Combed ring spun yarns

4.2.1. Pre comber drawing

For combed ring spinning, the Drawframe is first used to process the card sliver and produce sliver, which issuitable for the Comber Lap forming step. It is very important that the sliver in the cans feeding the lap windershould be of consistent length from can to can, and be coiled so that it is withdrawn without interruption. Becauseof the large number of cans behind the lap winder, any defective coiling and sliver withdrawal causes excessivemachine downtime and loss of efficiency.

4.2.2. Post comber drawing

The successful development of the RSB autoleveller Drawframe has led to use of only one drawing process afterthe comber. This results in significant improvements by producing a finisher sliver with more sliver cohesionwhich improves sliver handling and processing at the roving frame.The Drawframe must be set with low-tension draft, particularly between the scanning rollers and drafting systemand between the drafting delivery rollers and the coiling into the can. Sliver stretching should be avoided.

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4.3. Rotor spun yarns

Rotor spinning opens and separates the fibres of the sliver to enable a yarn to be formed by the rotor groove. Theorientation of the fibre in the sliver is not critical to the rotor spinning system and fibre hooks do not play a majorroll in spinning system.It is normally recommended that two processes of drawing be used as preparation to obtain:

increased yarn strength, increased dust and trash removal, increased blending action, processing security at a low cost increase.

There is a trend to use only one process of autoleveller drawing as preparation for rotor spinning. This has beensuccessful in the manufacture of knitting yarns where yarn strength is not a major criterion. However, a changefrom two processes of drawing to one process may need considerable improvements to be made in the blowroom

and card room to meet the yarn quality and spinning performance requirements.

4.4. Air jet spinning (MJS) and Vortex spinning (MVS)

In the world market Air Jet and Vortex Spinning plants are relatively few, but they impose special sliverrequirements for the high speed, high draft systems to work well. The sliver is drafted up to 150 : 1 and deliversyarn up to 400 m/min. The drafting system requires a sliver with:

Well-oriented and individualized fibres in the sliver,

low level of slubs < 1 / kgno clearer waste, < 0.5 / kglight sliver weight, typically 35 to 50 gr/yard,uniform sliver with < 3.2 CV%. (But not the absolute minimal)low nep count < 70 /gramshort Fibre Content < 4.5 %no sliver damaged by defective cans or by the operators moving cans.

4.4.1. Suggested start-up check list for MJS and MVS

Installation CriteriaFinisher sliver For MJS PES / CO blends(3 Process System)

Spectrogram - Without faults (No drafting waves or peaks) with autoleveller off.

Uster diagram - Not more than 5 spikes exceeding +/- 10% in 100 meters of sliver.No spike exceeding +/- 15%.

Sliver CV% - Finisher sliver CV% is dependent upon the fibres used, prior processing, and blend level.CV% should be minimized to within the range of 2.2 to 3.2% without damaging fibre,compromising sliver cohesion, or increasing quality cuts and ends down

One yard Uster CV% - In the range of 0.3% to 0.8% (preferably below 0.6%).

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Within plant sliver weight variation - 5-m lengths, weight CV% should not exceed 0.3%

(5 samples from each of 10 cans within the plant.

Stop rate Machine should run for at least 1½ hours without a draft zone or coiler stop.

Process guidelines – Drawing system for MJS

The following chart was compiled by a team from ARCO, Murata in Charlotte and ITT in Charlottesville, VA. Itshows the recommended settings for the different drawing processes.

RSB-D 30 basic guidelines for MJS

(Produce Finisher Sliver of 34 - 55 Grain /yd, from 1.5″ PES / CO blends)

For Yarn For YarnNe 22 – 40 Ne 12 – 24

First Pass Second Pass Finisher Pass

# Ends up x grs./yd. 6x 64-68 6x 52-68 5x 40-57 6x 47-52Total fed wt. grs / yd. 385 - 410 310 - 410 200 - 285 280 - 310Scanning roller size N/A N/A 5 or 4 mm 5 or 4 mmScanning roller load N/A N/A 120 120Main draft distance 40 - 44 40 - 44 38 - 43 38 - 43Break draft distance 44 - 48 44 - 46 44 - 46 44 - 46Break draft 1.41 – 1.7 1.41 – 1.7 1.28 – 1.41 1.28 – 1.41Total draft 6.0 – 8.0 6.0 – 8.0 5.0 – 7.5 5.0 – 7.5Delivery grs./yd. 52 – 68 40 - 52 34 - 40 41 - 55

Top roll material Day Int’l. type 764AL, peach colour, 72 shore hardness

Web funnel insert 7 or 8 mm 6 to 8 mm 5 to 6 mm 6 to 8 mmCondenser size 3.5 to 3.8 3.0 to 3.5 mm 2.5 to 2.8 mm 3.0 to 3.5 mCoiler tube size 29 mm 29 mm 24 mm 24 mm

Coiler speed Minimum with no kinks

Delivery (m/min) 500 – 700 500 – 650 600 600Can filling Clear of can sidesRoom conditions 24 – 26 deg.C (75 – 79 deg. F). 50 – 55% RH

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4.5.1. Compressed air

The Drawframe requires compressed air of a minimum pressure of 6 bar and a maximum pressure of 8 bar.The air is used to:

pneumatically load the drafting system, assist in threading the sliver into the funnel and condenser, maintaining a clean funnel, cut the sliver, pneumatically load the scanning rollers, clean the filters screen where applicable.

4.5.2. Exhaust air / suction

The exhaust air needed for an integrated suction system and for a central suction system has to be sufficient toeffectively transport dust, fibre and trash from the machine.The air requirements are:

Suction under pressure for both systems of 12 to 15 mbar. (120 to 150 mm WS)Central system suction of 800 to 1000 cubic meters / h. (480 to 600 CFM)Integrated system suction of 1000 to 1200 cubic meters / h. (600 to 700 CFM).


Recommended room conditions for drawing some different fibres are:

TemperatureMaterial RH %

Deg C Deg Fg. water / kg air

Cotton 40 – 50 24 – 26 75 –79 8 – 11

Cotton with highhoneydew

40 – 45 24 – 26 75 – 798 – 9

High water contentIncreases stickiness

Polyester 50 – 52 24 – 26 75 – 79 10 – 11

Viscose / Polyester 48 – 54 24 – 26 75 – 79 10 – 12

Cotton / Polyesterblends

45 – 50 24 – 26 75 –79 9 – 11

Wool / CashmereWool / Angora

60 – 70 24 – 26 75 – 79 12 - 14

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5. Troubleshooting

Normally, when a possible problem is presented, the challenge is to establish whether the problem is related to:The machine,The material,Machine component compatibility,Processing technology.

5.1. The machine

It is important that the machine be carefully examined to be sure that it is in a correctly functioning condition.Check:

All surfaces should be free of burrs, rough places, or cuts.Contamination from fibre finish of trash should be removed.The pneumatic pressure should be correct and the drafting rollers applying the appropriate forces.The suction system for the waste removal should be correctly functioning.The cans in the coiler should be positioned correctly.

5.2. The material

Check for any CHANGE of the materials or process since the machine was last adjusted. This includes,Fibre types and blend levels.

Sliver weight and number of doublings at the Drawframe. Any change in the preparation process, such as blowroom, carding, combing or drawing.Processing speeds. Any of the above changes can require additional optimization of the Drawframe set up.

5.3. Machine component compatibility

Check that the changeable components are correct for the material in process:Scanning roller and sliver funnel size.Top roller cots are in good condition and of a suitable material.Insert funnel and trumpet diameters.Coiler tube inside diameter.Processing Technology

Good processing technology is dependent upon the overall condition of the machine being in order. For thisreason, any mechanical defect in the machine must first be corrected. Similarly, any visually obvious processingfault should be corrected such as:Sliver tensions throughout the process should be minimized, but not to the point of creating loose sliver.Slivers should not cross or roll over each other as they go through the machine.Slivers should not be damaged by any component such as,Incorrect positioning of sliver funnel or scanning rollers,Damaged cots on the top rollers,

Damaged coiler tube,Damaged coiler plate.

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5.4. Basic sliver quality check

After the mechanical and visual checks have been completed, basic sliver checks have to be done using thetesting lab equipment to see if the problem remains. The following can be used as a guideline to systematicallyaddress the quality issues:

5.4.1. Uniformity

Using an evenness tester obtain the sliver diagram, the spectrogram and the evenness data which includes CV%.If the Drawframe has a leveller, tests should be done with both the leveller switched “ON” and “OFF”.Compare the ON and OFF results to see if the problems are similar or if the leveller improves the sliver.For consistency set the sliver evenness tester to run at 50 m/min: the maximum scale at + /- 25 %: and the paper

speed at 10 cm/min. With this setting, one cm of paper represents 5 m of sliver, and each heavy horizontal line isa 5 % change.With leveller off , look at the diagram for spikes and obvious waves.

5.4.2. Sliver spikes

Sliver spikes are normally created when the roller settings are too close or possibly the break draft is too low.Check Roller settings and fibre length and re set if necessary. Follow the recommendations in the machinemanual or in the previous section on roller settings.It is helpful to manually feel the drafting resistance in the break draft zone. It should be possible to press a feelergauge into the sliver between the first two pairs of rollers.

0 25 50 75 100 125 150 175 200

Evenness Diagram showing Spikes

0 25 50 75 100 125 150 175 200

25201510

0101520

25

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5.4.3. Visible waves in the diagram

Waves that can be obviously seen in the diagram are usually caused in the previous process or processes.

Diagram showing obvious waves

0 25 50 75 100 125 150 175 200

25201510

010152025

Keep in mind that any waves produced in a preceding process will be extended by an amount equal to thesubsequent total draft.It is possible for previously created drafting waves to be rectified by using the autoleveller Drawframe. However,the sliver quality after the leveller will always be better when the in-feed material is fault free.Check several samples of sliver being fed to the Drawframe and see if corrective action is required at thepreceding process.

5.5. Spectrogram drafting waves

The Spectrogram is most useful in that it shows where there are periodic faults in sliver, roving or yarn. There isan Ideal spectrogram for each type of staple fibre, and there is a “normal” spectrogram form for each process thatis slightly different from the ideal form. In all cases the normal spectrogram should have a smooth shape from firstline at about the 2-cm wavelength, to the second line at about 6-cm wavelength. The curve height then graduallyreduces, approaching the base line at the 50-m wavelength.(For man made fibres the normal high point is at a longer wavelength depending upon the staple length andstaple diagram).

Sliver drafting waves extend above the normal spectrogram form and creates a hump. The hump usually extendsfrom 1.5 to 3 times the staple length with WL of the highest “mean” point at about 2.25 times the staple length

It should be noted that a drafting wave hump is extended in the spectrogram by any subsequent drafting action.For example, a drafting wave created in the break draft zone would have a hump mean value of approximately 5cm, but which will be extended by the main draft to approximately 25 cm depending upon the amount of the maindraft.

Drafting waves are caused by:Uncontrolled fibres in the drafting zone,Short, floating fibres,Incorrect roller settings,Insufficient drafting roller pressure,Wrong type of top roller cot

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5.5.1. Sliver mass waves are caused by:

Stretching the sliver in the process,Wrong type of sliver funnels or condensers (inside diameter too small),Incorrect Sliver tension in the coiling action (tension too high or too low).

Ideal and Normal Spectrogram

Main Draft Zone Wave

Break draft Zone Wave extended by theMain Draft

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Break Draft Too High orRollers are Too Open

Break Draft Too Low orRollers Too Close

5.5.1.1. Break draft zone

Break draft is too low, orBreak draft rollers are too close,

Creates drafting waves in the main draft zone

Break draft is too high, orBreak draft rollers are too open.

Creates drafting waves in the break draftzone that are then extended by the maindraft.

5.5.1.2. Main draft zoneMain Draft Rollers Too Close

Drafting waves can be created in the maindraft zone by incorrect roller settings, eithertoo close or too open. The spectrogram canappear similar in both cases.Main draft roller distance (HVD) set too close.Staple length of man made fibres was 38 mmand HVD = 39 mm

Drafting wave hump from channel 7 cm to

10 cm.Main Draft Rollers Too Open

Similarly,Main draft zone HVD set too open,Staple length 38 mm and HVD was 47 mm.

Drafting wave hump from channel 6 cm to10 cm.

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Main Draft Rollers Optimized

Roller setting minimized the drafting wave.HVD = 43 mm

5.5.2. Drafting system pressure

When the drafting system pressure is not in order, the drafting action is out of control and spectrogram waves canbe seen in the range of 12 to 50 cm. This loss of control can be due to:

Drafting system pressureLoss of sliver control

Insufficient drafting pressure.Sliver guides incorrectly located andcompacting the slivers on one or both sides.Slivers rolling over each other prior toentering the draft zone.

Undrafted thick places that will be seen asspikes in the sliver diagram.

5.5.3. Levelling action waves

The levelling action point has to be carefully adjusted to function correctly. If the LAP is too early or too latespectrogram waves will be visible. It is necessary to use the spectrogram when setting the LAP.

Leveling action pointToo early

Levelling Action Point “E” too early. As an example, the faulty hump has a highpoint at a wavelength of approximately 50 cm.

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Leveling Action PointToo Late

Levelling action point “E” too late.Example: The faulty hump has a high point ata wavelength of approximately 30 cm.

NOTE:These LAP related spectrogram characteristics could appear if the sliver guides are re-adjusted or the

sliver entry tension is changed. These actions can require a further adjustment of the LAP.

5.5.4. Sliver tension waves.

If the sliver tension, prior to drafting, is too low, the sliver guiding components are not effective.Slivers will roll over each other.➯Spectrogram waves can occur as break draft waves extended by the main draft or as main draft zone waves.

5.5.5. Sliver delivery tension waves.

If the delivery tension is too high the web being pulled from the delivery rolls is stretched and the sliver becomesuneven. The sliver stretching occurs at the weakest regions that coincide with the dominant drafting waves. Theeffect is to amplify the wave form rather than to extend the wavelength.

Coiler Speed Too LowCombed Cotton 35 mm

5.5.6. Coiler tension waves

If the coiler speed is not correct, the sliver willeither be folded when it is too low, or it will bestretched when it is too high.When the coiler speed is too low and sliverfolding occurs Spectrogram waves can beseen in the range of 1.5 to 3 cm.

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Coiler Speed CorrectedCombed Cotton 35 mm

This characteristic is very evident in combedcotton.These waves can be confused with main draftzone waves.

5.6. Spectrograms of mechanical and periodic faults.

Mechanical faults create sliver mass irregularities that can be seen in the spectrogram as falling into one or twoadjacent channels. These are sometimes referred to as “chimneys”. A mechanical fault creates a defect that isthen extended or drafted out by the drive mechanisms or by the drafting action. By considering a specificspectrogram wavelength, the gearing layout and the change gears used, it is possible to limit the possible causesto one or two elements.

Many periodic faults show up as a spectrogram peak at a wavelength WL, but in addition, one or more peaks arevisible as harmonics. These harmonic wavelengths are usually at WL / 2, WL / 3, WL /4 …. When multiple peaksare visible with this relationship, the true wavelength is the longest one.

5.6.1. Draft roller defects

The following guidelines are:

Front Top Roller, Out of RoundFor a defective roller the wavelength(WL) = Roller circumference x draft occurringafter the defective roller.

WL = (d x π

x V).= 3.8 cm x 3.14 x 1.0= 12 cm

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Front Top Roller, Oval ShapedIf a roller is oval, the high and low placesoccur twice each revolution and the WL in the

spectrogram will then be

WL = d x π x V2

= 3.8 cm x 3.14 x 1.02

= 6 cm

Front Top Roller, Oval Shaped

If the top roller cot-surface is defective thedefect can show up as a 12 cm or a 6 cmpeak.

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5.6.2. Use of gearing diagram to relate components to WL

By referring to the gearing diagram and using the appropriate change gears, pulley diameters, drafts, coiler andcan information, the cause of a spectrogram wavelength can be identified. The following chart shows RSB-D 30relationships between components and wavelengths, but it can be used as a guide for other RSB machines.

Spectrogram Wavelengths Created by Machine Components

WL

WL Depending on draft

Independent of draft

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5.6.3. Spectrogram peaks of scanning rollers and drafting system

The following table shows the various defect wavelengths depending upon the drafts.

Wave length WL [cm]

At VZW = 1; VZ = 1; VE = 1; VA = 1

At total draft V:

Machinecomponent

4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5

WL = d x π x V [cm]

133 148 162 177 192 207 221 236 251 266 280 295 310 325 340

42 47 52 56 61 66 71 75 80 85 89 94 99 104 108

Scanning roller

D4= Ø94mm

Back roll (4)D3= Ø30mm

Top roller (1)Above back rollØ38mm 54 60 66 72 78 84 89 96 101 107 113 119 125 131 137

A t

b r e a k

d r a

f t V V :

V

WL = d x π x ------- [cm]

VV

1.16 36 41 45 49 53 57 61 65 69 73 77 81 85 89 93

1.28 33 37 40 44 48 52 55 59 63 66 70 74 77 81 85

1.41 30 33 37 40 43 47 50 53 57 60 64 67 70 74 77

Middle roll (5)D2=Ø30mm

1.70 25 28 30 33 36 39 42 44 47 50 53 55 58 61 64

1.16 46 51 57 62 67 72 77 82 87 93 98 103 108 113 118

1.28 42 47 51 56 61 65 70 75 79 84 89 93 98 103 107

1.41 38 42 47 51 55 59 64 68 72 76 80 85 89 93 97

Top roller (2)abovemiddle roll

Ø38mm

1.70 32 35 39 42 46 49 53 56 60 63 67 70 74 77 81

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5.6.4. Periodic faults due to dirty or defective timing belts / flat belts

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5.6.5. Periodic faults due to guide and tension rollers

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5.6.6. Periodic faults of coiling and can filling

Trash accumulation in the coiler tube or a mechanical defect in the coiler head can cause spectrogram spikes atthe wavelength corresponding to circumference of the coil. (WL = Coil diameter x 3.14 cm) The spikes at theharmonics can also be visible.False coiler peaks

The formation of the sliver column creates compressed zones of sliver at the inside and outside of the coil. Thesecompressed zones contain a different amount of moisture that is detected as being a sliver mass change. Thesezones do not create defects as the sliver is subsequently processed unless the can filling is excessive andcauses sliver disturbance.

By passing the sliver through the evenness tester two or three times, the deformations are removed,moisture is normalized and the coiler peak should disappear. If the peaks persist, the machine should be checkedto find the cause.

Spectrogram spikes due to coiler and can diameters.

CanDiameter DK

[mm]

CanDiameter DK

In inch ['']

Sliver coilDiameter A

[mm]

Wave length

WL = A x π [cm]

WL/2[cm]

225/250 9/10 170 53 27

300 12 195 61 31

350 14 220 (214) 69 (67) 35 (34)

400 16 252 79 40450 18 286 (300) 90 (94) 45 (47)

470 18,5 300 94 47

500 20 320 (316) 101 (99) 51 (50)

600 24 380 119 60

800 32 252 79 40

900 36 286 (300) 90 (94) 45 (47)

1000 40 286 (300) 90 (94) 45 (47)

( )Sliver coil diameter A at: Sliver duct BK Ø 39 mm

Coiling into cans of 800,900 & 1000 mm diameter

Coiling into cans of225 to 600 mm diameter

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5.6.7. Causes of 40 and 50 cm Spectrogram Faults.

The spectrogram faults found in the 40 and 50 cm wavelengths have to be identified as either “Peaks” which fallinto one or two channels, or as “Drafting Humps” that cover several channels.

A second classification should be performed to see if the spectrogram fault changes wavelength if the draft ischanged.

A third classification should be done by comparing results with the autoleveller “ON” and “OFF”. Additionally, atest can be done by passing the fed slivers over the scanning rollers of the autoleveller to see if the rollerscontribute to the problem.

A test should be done to see if the Spectrogram fault diminishes or disappears by passing the sliver several timesthrough the Evenness tester, - shows it is “not a real fault”.

40 and 50 cm WL Faults due to Sliver Deposit.

Coiler Speeds incorrect ► bunched sliver ► False Fault► sliver drafted ► REAL Fault.

sliver tube dirty or damaged ► REAL fault sliver taken from “overfilled” sliver can ► REAL fault sliver from top of normal can ► False fault sliver stored for an excessive time before testing ► False fault.

40 and 50 cm WL faults related to fed sliver.

Normally humps due to stretching of slivers prior to the drafting zone.Combed cotton slivers are vulnerable to this problem.

40 and 50 cm WL faults due to incorrect settings.

Levelling action point – Shows up only when autoleveller is “ON”.Scanning roller clearance at 0% - error close to limit.VA too high (critical for combed cotton).VE too high.

5.6.7.1. Faults of 40 and 50 cm WL faults due to mechanical parts

Defective back rollers, including drives and bearings.Middle rollers, including drives and bearings.Draft system weighting not evenly distributed.Bevel gear drive where applicableBelt tension rollers on drives to back and middle rollers.Pressure sleeves for NW1, NW2, W4 (incorrect tightening torque).Shaft couplings for NW2-NW4 (ends of shafts not aligned).Tension too high on timing belts for NW1/NW2 and planetary gearbox.Defective planetary gearbox.

Coiler drive disc distance “s” not uniform at the circumference.

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5.6.7.2. Faults of 40 and 50 cm WL due to electronic components

B91 can create a drafting hump but only when the autoleveller is “ON”.Servomotor can create a drafting hump when the autoleveller is “ON”.

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6. UNIlap /Combing Preparation


1.1. Introduction 3

1.1.1. Functional description 4

1.2. Principle features 5

1.2.1. Creel 5

1.2.2. Drafting units 5

1.2.3. Batt calender system 5

1.2.4. UNIlap winding unit 5

1.2.5. VARIOspeed (optional) 6

1.2.5.1.

VARIOspeed 6


2.1. Function of the UNIlap 7

2.2. Batt cohesion for the winding process 7

2.2.1. Batt weight / fibres in the cross-section 8

2.3. Raw material 8

2.4. Lap winding delivery speed 9

2.5. Total draft in the preparation for combing 9

2.6. Aspects of lap quality 10 2.7. Uniformity of lap build-up 10

2.7.1.

Controlled winding avoids lap weight drift 11

2.8. Lap hairiness 12


3.1. Creel 13 3.1.1. Sliver deflection pulleys 13 3.2. Drafting system 14 3.2.1. Sliver guides 14 3.2.2. Feed roller and fleece guides 14 3.2.3. Guidelines for adjusting sliver guides 15 3.2.3.1. Good spread 15

3.2.3.2.

Bad spread, wide 15

3.2.3.3. Bad spread, narrow 15 3.2.4. Draft roller 16 3.2.4.1. Top roller 16 3.2.5. Break draft 16 3.2.6. Main draft 16 3.2.7. Total draft 16 3.3. Adjustment of the tension bar 17 3.3.1. Adjustment of fleece guides 17 3.3.2. Table calender tension draft 17 3.4. Calender section 18

3.4.1.

Calender roller relative to the lap roller 18

3.4.2. Calender to lap roller draft 19 3.5. Lap winding 19

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3.5.1. Tension too low 19 3.5.2. Tension too high 19

3.6.

Lap roller flanges 20 3.6.1. Adjusting the yoke position 20

3.6.2. Lap roller flange pressure 20 3.6.3. Lap winding contact pressure. 20


4.1. Overview of preceding processes 22 4.1.1. Blowroom and carding 22 4.1.2. Pre drawing 22 4.1.3. Handling practices 23 4.2. Summary of recommended settings 23

4.3.

Air requirements 24

4.3.1. Exhaust air / suction 24 4.3.2. Room conditions 24


5.1. Lists factors that influence the lap characteristics 25

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1.1. Introduction

The cotton combing system permits cotton to be spun into fine ring spun yarns. Without the comber only a verysmall percentage of expensive cotton would be commercially spun into carded yarns finer than Ne 40/1 (Nm 68).

The combed yarn system is relatively expensive compared to carded yarn system: long, fine, good quality cotton is needed

the cotton is relatively expensive the comber removes short fibre (noil), - from 10 to 20 % noil depending the cotton type and the yarn counts

to be spun. the fibre preparation and the combing process have to be optimized and controlled to minimize good fibre

waste by effective short fibre selectivity.

The comber has to be supplied with a set of laps and the majority hooks should be leading as the material entersthe comber.The carding action taking place between the card cylinder and the doffer results in the majority of fibre hooksbeing trailing hooks: 50% trailing hooks

10% leading hooks 10% double hooks

There must be two sliver reversals between the card and the comber for the majority hooks to be leading enteringthe comber. In the modern system a single drawing process followed by the UNIlap satisfies this requirement.

UNIlap systemMajority hook positions in the combing preparation.

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The UNIlap converts drawn sliver to a wound batt as preparation for combing and has the following productionfeatures:

Raw material is cotton up to 60 mm in length, feed weight up to 160 ktex (g/m) or 2250 g/yard. – 28 ends up of 5.7 ktex or 28 ends of 80 g/yard. delivery batt weight 60 to 80 ktex or (845 to1125 g/yard.) lap weight up to 25 kg. lap width 300 mm. lap diameter up to 650 mm. production rate up to 360 kg/ hr. delivery speed is variable between 50 and 120 m/min depending upon the raw material.

1.1.1. Functional description

UNIlap principle of operation

Feed from 28 cans of drawing sliver (5), 14 cans / side. Slivers are guided by a stationary creel (4).

The slivers are assembled and fed to the two drafting zones (9 and10). The drafted slivers emerge from the drafting zones as two “fleeces” (8). The fleece from the drafting head (9) is laid on top of the fleece from head (10) as it passes underneath. The two layered fleeces are drawn into the head (2) of the UNIlap by the calender rolls (3) The calender rolls strongly compress the fleeces to form a “Batt” The batt is then wound onto a tube by the lap rolls (1) and controlled in width by the lap roll flanges or

winding discs (7). When the lap is fully wound it is automatically exchanged for an empty tube (6)

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1.2.1. Creel

The sliver cans in the creel can be up to 1000 mm diameter and 1200 mm in height. The sliver is pulled over astatic creel. There is a stop motions for each sliver (which will monitor the sliver movement).The creel height can be adjusted to allow sliver ballooning between the cans and the creel without dragging overthe sliver column.

1.2.2. Drafting units

Each drafting unit is a 3 over 3 system with two draft zones, break draft zone and a main draft zone.

The back and middle bottom rollers have straight grooving and the front bottom roller has a spiral groove. The top rollers have rubber cots of 83 shore hardness. The break draft and the main draft can be individually adjusted. The top rollers are pneumatically loaded. The pressure of up to 1600 N per roller is controlled by a central

setting. A stop motion is provided to stop the machine in the event of a roller lap.

1.2.3. Batt calender system

There are four calender rollers that compress the batt before feeding it to the first Lap roller.

The rollers are loaded through a leaf spring arrangement that exerts a calender load pressure of up to16’000 N.

1.2.4. UNIlap winding unit

Key:

1 Calender rollers2 Lap rollers

3 Lap tube4 Loading frame (yoke)5 Pivoted lever6 Loading cylinder7 Control lever8 Lap9 Pressure reducing valve10 Adjusting screws

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The calender rollers (1) are followed by the two lap rollers (2) between which the Lap (8) is formed. The surface of first of the lap rollers is grooved to positively drive the lap, the surface of the second lap roller

is smooth The perforated lap tube (3) is held in place by the winding discs on each of the lap rollers. As the lap is wound onto the tube, the system exerts a load of up to 10,000 N to created a firmly wound lap. A negative air pressure of 350 PA is provided inside the lap tube to secure the lap end upon the start of

winding. As the lap builds up in diameter and weight, the pressure exerted by the loading cylinder (6) is varied to

ensure the required pressure of the lap against the winding rollers.

1.2.5. VARIOspeed (optional)

To maximize delivery speed and obtain optimum lap quality a VARIOspeed feature is available. At the small diameters it is possible to wind at higher speeds than at larger diameters. When the winding speed isconstant throughout the build, it is below the maximum possible speeds at the smaller diameters and above theoptimum quality speeds at the larger lap diameters.To meet the challenge of high production the VARIOspeed was developed.

1.2.5.1. VARIOspeed

For increased production and improved lap quality

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2.1. Function of the UNIlap

Combining a number of slivers into a lap that is ideal for the combing operation. Creating a batt with sufficient cohesion to ensure good lap winding. Orienting the fibres to the point that they are optimal for both the lap condition and combing action. Produce a batt in which the fibres are uniformly distributed in the batt cross-section. Supply laps that will have good unwinding characteristics on the comber.

2.2. Batt cohesion for the winding process

Batt cohesion is a function of the batt mass and the batt breaking length.

The batt mass is determined by the number of fibres in the cross section and the fibre fineness. The batt breaking length depends upon:

- Raw material, i.e. friction coefficient, surface characteristics and type of cotton.- Combing preparation system, intensity of the blowroom equipment, type and production rate of the

cards, and the drawing/ lap preparation machines.- Density of the fibre mass.- Total draft between the doffer of the card and the lap winder.

The advantages of high batt breaking strength are:- Increase in productivity,- Improved lap quality,- Better unwinding at the comber,- Lap weights can be increased. With most cotton types, good quality laps of between 23 and 25 kg can

be produced.- With relatively short types of cotton, the batt strength is lower and consequently the maximum lap

weight is lower.

Lap weight relative to staple length

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The preferred upper limit of batt breaking strength is around 10 N. With the most commonly used cottons this isachieved when the cross-sectional fibre count is approximately 550’000 fibres.

Additionally, the batt weight should be limited to not more than 80g/m (1125grains/yd).

2.2.1. Batt weight / fibres in the cross-section

The following chart shows the relationship between batt weight, fineness and the fibres in the cross-section. It canbe used to see if a condition is within the recommended limits.

Batt weight and fibres in the cross-section.

2.3. Raw material

Long and fine fibres exhibit higher fibre-to-fibre friction and this results in a greater batt breaking length.Short and coarse fibres have lower fibre-to-fibre friction and this results in a reduced batt breaking lengthThe fibre surface quality, the degree of fibre maturity and the fibre crimp, each have an influence on the frictionforces.

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2.4. Lap winding delivery speed

The maximum lap winding delivery speeds are influenced by the cotton staple length and the tolerable degree oflap hairiness. With shorter cotton the critical level is reached at lower speeds than with longer cotton. Thefollowing chart shows typical speed limitations for different cotton lengths.

UNIlap delivery speed for various cotton staple lengths

2.5. Total draft in the preparation for combing

Over the years combing preparation included maximizing the number of doublings to mix slivers to obtain aconsistent lap. This necessitated a relatively high level of draft. The higher the draft the greater the degree of fibreorientation in the batt and the more the batt tends to split at the comber.

Batt breaking length related to total draft

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With the improvements that have occurred in blowroom and cards, the variations of mass and quality have beengreatly reduced. This has led to the realization that there are clear benefits to be gained by reducing the total draft

in the preparation of comber laps: fibre orientation is reduced, batt breaking length is increased, care has to be taken with longer fibres because the batt resistance to combing is increased and longer fibres

could be damaged. This is resolved by using lighter batt weights for longer staple fibre.

Drafts of 7 to 10 are the recommended total drafts between the card doffer and the lap winder.Where there is a roller-drafting element at the card exit the quality of the card web and the degree of draft has tobe taken into consideration.

If the web on the doffer has been increased in weight to produce a very heavy sliver the fibre orientation andfibre entanglement will be increased. The combined draft at the card delivery section may then be well below

two. This may mean that the coiled sliver is not, in effect, drafted and should not be considered as part of thetotal draft between card and lap winder.

If the card web is not excessively heavy and the combined draft at the card delivery section is two or more,then a “real” draft takes place and this should be considered as part of the total draft between card and lapwinder.

2.6. Aspects of lap quality

The quality of laps is judged by the physical properties and the performance in unwinding at the comber. Primarilythey fall into the following categories: homogeneous lap build-up, no lap weight drift in winding, minimal lap hairiness during unwinding at the comber, optimal fibre arrangement in the batt for good fibre selectivity on the comber, no lap damage in transportation between the preparation and the comber.

2.7. Uniformity of lap build-up

The batt mass consistency, CV%m, depends upon the uniformity of the slivers being supplied to the UNIlap, butis also influenced by: the batt breaking strength the geometric or constructive machine conditions to avoid lap weight drift the machine settings and drafts

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CV%m of the Batt Related to the Batt Breaking Strength

If the batt breaking strength is too low, the working of the lap in the winding process disturbs the lap and createsshifts in batt mass. Additionally, if the batt is disturbed in the winding process the individual layers becomeseparated and tend to split when unwinding at the comber.

Under normal conditions the UNIlap can be set to produce laps with a CV%m of 0.3 to 0.5%.

2.7.1. Controlled winding avoids lap weight drift

To ensure a drift-free lap, the winding head is equipped with a pneumatic lap pressure control device. Thisregulates the lap pressure against the lap winding rollers to compensate for the change in the winding geometryas the lap increases in diameter and weight.Throughout the lap build-up the pressure exerted on the yoke is progressively increased.

Uniform lap build-up by controlled force

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Optimum Force during build-up by Pressure Control

At the beginning of the lap winding, the lap is pressed firmly into the “Vee” between the winding rollers and thiscreates a high compressing action with a relatively low pressure. As the lap diameter builds up, the lap tends toride on top of the winding rollers. To obtain consistent lap compression the pressure has to be increasedthroughout the build.

2.8. Lap hairiness

Since the lap surface is made up of loose fibres, a certain degree of hairiness is unavoidable. However, if the laphairiness exceeds a certain level it can have an adverse effect on the combing performance and the spun yarnquality. It is desirable to produce laps with the minimal amount of hairiness.

Factors influencing lap hairiness, in order of impact, are: fibre material, (short fibre, bulky crimped fibre increase hairiness) xxxx total draft in the combing preparation, (Low draft is best), xxxx combing preparation system, (Drawing vs. Ribbon lap preparation) xxx pressure during lap build-up on the UNIlap, xx UNIlap winding speed, (depending upon the raw material), xx

tendency of material to stickiness, (Cotton region and type), xx type of pre-Drawframe and settings, xx settings of the drafting section of the UNIlap, xx room air conditioning, x lap moisture content. x

As there are so many factors influencing the lap hairiness, it is necessary to encourage the plant management tomonitor lap appearance and detect when hairiness changes so that corrective actions can be effectively taken.

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3. Machine Elements

Creel and can layout for 1000 mm cans

3.1. Creel

The location of the sliver cans should be predetermined and a layout supplied with themachine.

The size of the cans and space available in theplant determine the configuration of the creel.

It is VERY IMPORTANT that the cans be locatedas planned to avoid uneven stretching of theslivers as they are pulled through the creel.

3.1.1. Sliver deflection pulleys

The sliver passes from the creel to the sliver deflection pulleys located above the drafting systems. Each pulleycorresponds to creel and can position and is now colour-coded to make it easier to identify the sliver path. Theslivers must stay in their designated deflection pulleys

Omitting slivers.In the event that slivers have to be omitted from the creel: Always omit slivers at the outside. Omit slivers from the rear drafting zone (10) first and then, if necessary from zone (9)

Sliver deflection pulleys

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3.2. Drafting system

The slivers must enter the drafting system in a correct condition to enable the drafting unit to control the fibresand produce a good quality fleece.

3.2.1. Sliver guides

The slivers pass from the sliver deflection pulleys through the sliver guides (5) and pass the feed roller (4) asshown in the figure below.

The sliver guides must be positioned at equal intervals. The slivers should be deflected as little as possible.

The width of the slivers entering the drafting zone is dependent upon The number of slivers being fed, The sliver weight, The type of cotton being processed, some cotton types tend to compact easily while others tend to remain

bulky. When the number of slivers is reduced, omit the outside slivers.

Setting the sliver guides

3.2.2. Feed roller and fleece guides

The sliver feed width has to be maintained as the slivers pass feed roller (4).The desired condition of the slivers entering the drafting zone is illustrated on the next page. However, as thefleece travels toward the head of the machine it tends to become wider.

To compensate for this, the width at feed (B) at the drafting unit farthest from the head of the machine should beset approximately 10mm less than the following drafting unit.

The fleece guides located immediately before the drafting rollers have to be set to prevent the fleece from

spreading wider than it was at the feed roller. In some instances it is preferable to be even slightly narrower thanthe width (B).

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3.2.3. Guidelines for adjusting sliver guides

3.2.3.1. Good spread

The slivers lie close to one another.

The distribution is even across the fleece.

3.2.3.2. Bad spread, wide

the sliver guides are set too wide, or the doublings are insufficient, or the slivers are too light.

3.2.3.3. Bad spread, narrow

Sliver guide is set too narrow.

The slivers are compressed into each other and therewill be a tendency to have slivers overlapping and the fibres will be difficult to draft, or the doublings are excessive, or the incoming slivers are too heavy

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3.2.4. Draft roller

The draft roller settings are made according to the staple length of the cotton. The following table can be used asa guideline nip distances.

Fibre length in mm Nip distances mmStaple length,commercial Zellweger

(F max) Almeter(1%)

Fibro-graph(2.5%)

Breakdraft

Maindraft

< 1 1/16″ 38 35 28.5 45 42

< 1 1/8″ 40 36 29,5 46 42

< 1 5/16″ 42 38 31 48 44

< 1 1/2″ 48 43 35 50 47

< 1 5/8″ 50 46 37 51 48

The minimum nip distance in the drafting system is 40 mm when the bearing blocks are touching. Therefore, agauge distance between the bottom of the blocks plus 40 mm will be the nip distance.

Roller nip distance = Gauge width + 40 mm

When setting the roller distances,Set the MAIN DRAFT ZONE then set the BREAK DRAFT ZONE.

3.2.4.1. Top roller

The top rollers must be set directly over the bottom rollers The front roller position is set and used as a reference point When the top rollers are pushed together the nipping distance is 40 mm and a gauge should be used to set

the identical spacing as the bottom rollers The top rollers must be parallel to the bottom rollers and to each other. All the top rollers must be of the same diameter, (39mm max, and 36mm min). As a result of buffing (grinding) the diameters of the top rollers are reduced. At 37mm diameter, shims must

be used to compensate for the reduction in diameter and maintain the required roller pressure.

3.2.5. Break draft

The break draft range is from 1.032 to 1.112.

3.2.6. Main draft

The main draft should be not less than 1.384. It is determined by the desired total draft of the machine

3.2.7. Total draft

For short and medium length cotton - 1.4 to 1.8 draft. For long staple cotton - Up to 2.0 draft.

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3.3. Adjustment of the tension bar

The tension bar can be used to control the width of the fleece. The edge guides can be opened or closed to influence the width of the fleece. The fleece width should be the same as the width of the lap being wound at the head of the machine.

Tension Bar Fleece Guides

3.3.1. Adjustment of fleece guides

The fleece guides can control the spreading tendency, but, as shown in the illustration, the edges of the fleece

must not roll and create a double thickness at the edges.

Table Calender Draft

3.3.2. Table calender tension draft

The table tension draft has to be adjusted to control the movement ofthe fleece from the drafting heads to the calender section.

The fleece must not be slack or too tight. The condition has to beobserved during the running of the machine

The change gear (E) affects the tension draft between the tablecalender rollers (2) and the winding calender rollers (1).

Available tension drafts: 0.999 1.009 1.019

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3.4. Calender section

The calender section compresses the combined fleeces and forms a compacted “Batt”.To prevent the batt from spreading as it passes through the calender rollers, guide rails and guide plates areprovided. The following diagram shows the control elements.

Guide rails and guide plates in the lap head

The guide rails (10) and guide plates (11 and 12) act to guide only the edges of the batt.They cannot modify the width of the batt.Sliver guides and fleece guides primarily control the batt width.

Adjustment without material: Set the guide plates (11and 12) at a distance of approximately 0.2 mm from the calender rollers. They must

not touch the rollers. Set the guide plates (13) at a distance of 0.2 mm from the surface of the lap roller. They must not touch the

lap roller surface.

Adjustment with material: Place the guide rails (10) and the guide plates (11and 12) against the edge of the batt, but without

compressing it.

Adjusting Calender Rollers3.4.1. Calender roller relative to the lap roller

The last calender roller delivers the batt to the laproller and the winding action.Setting procedure: Switch on the calender pressure, Set the distance between the calender roller

and the lap roller at 1 mm. Switch off the calender roller pressure, then

switch it back on, Check the setting and adjust if necessary.

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3.4.2. Calender to lap roller draft

The batt has to be under a slight tension as it passes from the calender rollers to the lap rollers. The normaltension is 1.0015, but can be increased to 1.0051 if necessary for longer staple.

3.5. Lap winding

Lap roller tension draft.The two lap winding rollers control the batt as it is being wound onto the lap tube. The first lap roller is fluted todrive the lap and the second lap roller is smooth to support the lap. It is necessary to carefully control the windingcondition. There has to be a slight speed difference between the two lap rollers to obtain a good quality lap.

The winding tension draft has to be adjusted afterexamination of the lap as it is being unwound at thecomber.

Lap roller tension draft As shown in the diagram,

3.5.1. Tension too low

Creases across the lap are visible.The smooth lap roller is turning too slowly.► Increase the draft.

3.5.2. Tension too high

Lengthwise creases are visible.The smooth roller is turning too fast.

► Reduce the draft. Suggested starting tension 1.0056.

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3.6. Lap roller flanges Setting of Lap Roller Flanges

The lap roller flanges have to beset relative to the lap rollers. There should be:

Clearance of 0.6 to 0.7 mm when thereis NO TUBE in place.

The yoke must be in the “tube loading”position.

Flanges closed without tubes.

3.6.1. Adjusting the yoke position

The yoke should be set to prevent the lap winding drums being damaged by the lap tubes.When the lap roller is in the tube loading position, there should be a clearance of 1 mm between the tube and thesmooth lap roller.

3.6.2. Lap roller flange pressure

The lap roller flange pressure has to be sufficient to prevent the laps from spreading, but should not exceed 8.5bar at the manometer.

3.6.3. Lap winding contact pressure.

The lap contact pressure affects the firmness of the lap as it is built up. The important features are described withreference to the diagram below:

Adjusting the winding contact pressure.

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During lap build up the pressure loading is increased as the diameter is increased.

The pressure applied at the small diameter is adjustable by setting the regulating screw (2), which increaseor reduces the initial pressure. Start with the pressure being between 1.0 and 1.2 bar but gradually increasethe pressure to produce a firm lap at the core.

When the yoke is in the bottom position, the pressure should not exceed 2.5 bar. The pressure regulator is controlled by the pressure bar (1) that moves against the regulator as the yoke is

raised. The pressure bar has a fixed distance (A) but is adjustable at the lower end (B). The distance (A) is 75 mm,

the distance (B) is between 79 and 81 mm. The difference between (A) and (B) should not exceed 6 mm. The setting (B) must be adjusted to obtain a firm lap throughout the build. The pressure exerted at the top of the yoke movement should not exceed 4bar. NOTE: As the lap winding pressure is changed the winding tension draft has to be checked and adjusted

when necessary.

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4. Recommendations

4.1. Overview of preceding processes

4.1.1. Blowroom and carding

The consistency of the fibre blending is very important if the UNIlap is going to produce laps of consistent quality,weight and performance. Any defect created, or allowed to pass through to the UNIlap will either interfere with theoperation of the machine or impact the combing operation.

The card web should be carefully controlled to produce good sliver suitable for combed yarn.

4.1.2. Pre drawing

The Drawframe should be set up to supply uninterrupted good quality sliver to the UNIlap.The following are very important: The metered length of sliver in each can should be correct. Cans with shorter lengths of sliver “run out” early

in the creel and GREATLY INTERFERE with the machine efficiency. The sliver coiled at the bottom of the can should be laid correctly and not entangled. The start up speed of the Drawframe, after a can change, should be controlled to lay the coils correctly.

The column of sliver in the cans should be clear of the can sides and not produce varying resistance to thewithdrawal of the sliver. The crown of the sliver column should not be excessive or create a dragging problem in the UNIlap creel. Sliver breaks in the can interfere with UNIlap running efficiency. Because of the large number of cans behind

the UNIlap, the condition of the draw sliver is critical to a good, efficient operation.

Additionally, the following table includes some recommended settings for the Drawframe feeding the UNIlap.

Setting Drawframe Remarks

Cylinder distance Do not set according to the bestCV%.Cylinder distance with goodCV% + 3 mm.

If the cylinders are too close together thecohesive length of the sliver is reduced,adversely affecting the running behaviour insubsequent processing stages.

Doubling or total draft fibre length

≤1 3/16" Max. 5-fold

≥ 1 ¼" Max. 6-fold

In order to ensure the necessary batt-cohesivelength in the subsequent processing stage.

Delivery up to max. 800 m/min. Depends on raw material.

Sliver weight at delivery3,7...4 g/m4 ...4,5 g/m4,5...5 g/m

For the following doubling on the UNllap:24...28 fold24...26 fold24 fold

Care should be taken to see that all sliver splices are draftable, otherwise they could cause a problem in theUNIlap drafting zone.

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4.1.3. Handling practices

Supply cans should be correctly located. The sliver path should be unobstructed with the least number of directional changes. The sliver tensions should be as equal as possible at the point of entering the drafting system Tension variations can lead to irregular sliver stretching, which in turn leads to uneven can run out. Endeavour to have sufficient cans available for the creel to avoid unnecessary waiting time at the creel

sliver change.

4.2. Summary of recommended settings

The following is taken from the UNIlap operating manual and should be used as a basic guideline.

Setting UNIlap Remarks

Cylinder distance Determined by the longest fibres in thebundle.Setting according to Instructions.

Depends greatly on raw material.

Break draft Break draft 1.032 - 1,112 fold

Main draft Not less than 1.384 fold Must be adapted according to the battweight.

Total draft Short and medium staple:draft of 1,4 - 1,8

Long staple: draft up to 2.0

Some yarn results may be better withhigher drafts, optimization trials areneeded.

Total draft in combingpreparation

The lower the total draft in combingpreparation, the less hairy the laps.Standard total draft combing preparation:7 to 10-fold

If the card is equipped with a draftingsystem, the corresponding draft must beincluded in the calculation of the totaldraft.

Pressure during windingup

Keep pressure setting at the end of the lap aslow as possible.If possible try at less than 2.5 bar

Excess pressure may lead to drift andmore hairy lap.

Lap roller change gears A/B

Standard setting = 1.0056 foldThe draft should be between 1.0056 and1.0087.Trial and error recommended.

Insufficient tension causes creases.Excess tension causes poor run-offproperties.

Calender lap roller

change gearsC/D

Standard setting = 1.0015 fold

Increased draft up to 1,0051 fold can beadvantageous on long staple material.Trial and error recommended.

Depends on raw material.

Batt weight Maximum 550'000 fibres in cross section,maximum 80 g/m.Depends on fibre fineness and applies to atotal draft range of 7 to 10 in the combingpreparation.

Increasing the batt weight also increasesthe tensile strength.Positive effect on the lap quality

► Page 22

Lap weight Fibre length

≥ 1 3/16" = 25 kg

Influence:fibre lengthbatt adherence lengthbatt weight

delivery speed► Page 24

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Delivery Fibre length

≤ 1 1/8until 90 m/min.

≥ 1 1/8until 120 m/min.

Look out for bubbles forming on the lapbetween calender rolls and fluted lap

roll.Too many bubbles cause hairy lap and,in extreme cases, creases form downthe length of the lap► Page 23



To be added later.


To be added later.

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5. Troubleshooting

5.1. Lists factors that influence the lap characteristics

Factor Influence on the Lap

Fine micronaire up to 3.5 and longstaple Approx. 1 1/2″

- Lap is less hairy- Higher winding contact pressure and heavier lap weights are

possible.

Coarser micronaire ≥ 4.0 and shorterthan 1 3/32″

- Laps possibly hairy,- Lower winding contact pressure – Lighter lap weights

Tension draft too high at winding - Hairy laps, poor lap cohesion.

Tension draft too low at winding - Creases are formed in the lap during winding.

Drafting settings not optimal - Hairy laps

Total draft too highDrawframe draft x UNIlap draft is over7 to 9. Cotton sensitive

- Hairy laps and poor lap unwinding, especially with shorter staple.

Batt guides andfleece guides

- If the batt is too wide or too narrow the lap edges will be irregular.- Re-set the fleece guides.

Winding contact pressure too high - Hairy laps.

-The lap layers tend to stick to each other. Layers tend to peel offduring unwinding at the comber.

- Poor yarn count variation.

Winding contact pressure too low - Lap weight is low,- laps are soft,- poor yarn count variation.

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7. Combing


1.1. Introduction 3

1.1.1. Advantages of Rieter combing 3

1.1.2. Current Rieter combers 4

1.2. Principal features 5

1.2.1. Machine characteristics of E61, E62, and E72 5


2.1.

Introduction 6 2.2. Benefits of combing 6

2.2.1. Extraction of short fibres 6

2.2.2. Extraction of impurities 6

2.3. Fibre selectivity 7

2.3.1. Fibre length distribution in combed slivers and noils 7

2.4. Factors influencing the combing result 8

2.4.1. Circular comb 8

2.4.1.1. Circular comb dimensions 8

2.4.1.2. Circular comb clothing 9

2.4.1.3. Cleanliness of circular combs 9

2.4.1.4. Service life of circular combs 10

2.4.2.

Top comb 11

2.4.3. Nippers 11

2.4.4. Feeding 12

2.4.5. Synchronization of movements 13

2.5. Yarn quality 14

2.6. Automation 15


3.1. Combing elements 17

3.2. Combing action and machine settings 18

3.2.1. Batt feed (backwards) 18

3.2.2.

Nipping 18

3.2.3. Rotary combing. 18

3.2.4. Nippers forward movement. 18

3.2.5. Web return. 19

3.2.6. Piecing. 19

3.2.7. Detaching. 19

3.2.8. Combing by the top comb 19

3.2.9. End of cycle 20

3.2.10. Removing noil from the circular comb 20

3.3. Nipper feed rate 20

3.3.1. Type of feed 20

3.3.1.1.

Forward feed 20

3.3.1.2.

Backward feed 20

3.4. Detachment setting (Ecartment) 21

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3.5. Circular comb 21

3.6. Top combs 21

3.7.

Piecing 22 3.7.1. Index disk – Setting the overlap 22

3.7.2. Spectrograms of piecings 23

3.8. Table funnel 24

3.9. Drafting 24

3.9.1. Roller settings 24

3.9.2. Draft distribution 25

3.10. Coiling 25


4.1. Start up steps 26

4.1.1.

Raw material 26

4.1.1.1. Long staple combing 26

4.1.1.2. Medium staple combing 26

4.1.1.3. Short staple combing 26

4.1.2. Machine condition 26

4.2. Recommended procedure for change of noil % 27

4.3. Impact of preceding processes 28

4.3.1. Bale laydown, blowroom 28

4.3.2. Carding 28

4.4. Lap formation 29

4.4.1. Lap splitting 29

4.4.2. Laps hairiness 29

4.5.

Air requirements 29

4.5.1. Waste / noil collection 29

4.5.2. Room conditions 30


5.1. Basic setting 31

5.2. Reduce neps in the sliver 31

5.3. Reduce the short fibre content in the sliver 32

5.4. Mean Time Between Assists (MTBA) 32

5.4.1. Table funnel stops 32

5.4.2. Machine cleanliness 33

5.4.3.

Lapping of the detaching rollers 33

5.5. Cloudy fleece 33

5.6. Recommendation to remove a low noil content from long staple cotton 33

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1. General Information

1.1. Introduction

The cotton sliver produced by the card contains several contaminants that interfere with the spinning of fine highquality yarns. There are trash particles, neps and up to 10% by weight of short fibres less than 0.5 inch (12.7mm). Additionally, the fibres in the card sliver are entangled, hooked and generally not aligned. To further preparethese fibres for the spinning of yarns finer than Ne 36/1 on the ring spinning or on the high draft “Vortex” system,the combing system is needed.

The primary function of the comber is to:

remove a substantial proportion of the short fibre as “noil”. effectively select the short fibre and minimize the quantity of long fibre in the noil. efficiently remove the trash particles and neps, Straighten and align the longer fibres collected as combed sliver. Produce a combed sliver that is compatible with subsequent spinning operations.

1.1.1. Advantages of Rieter combing

The primary benefits of combing are associated with the superior yarn quality and spinning performance whenspinning fine count cotton yarns.

The combing step also has a direct influence on the economics of yarn production. On the one hand, the finer,high quality yarn can demand a higher price, but on the other hand good fibre can be lost in the noil, which couldbe a negative aspect.Therefore the fibre selectivity of the comber is an important aspect of the operation. In this respect the Rietercombing machines have considerable advantages in that it is possible to produce an improved combed sliver athigh speed while removing a reduced percentage of comber noil.

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1.1.2. Current Rieter combers

The current Rieter combers are an out growth of a successful line of combers. Good combing quality and highproductivity have only been possible with engineering know-how. The recent use of the “Computer Aided ProcessDevelopment” – CAPD has led to advances seen in the latest models. As can be seen from the following, progress was made from the E 7/5 to the E 7/6, but it needed the CAPD topush performance to the levels of the E 62 and E 72.

Evolution of comber production:

200 225 250 275 300 325 350 375 400 425 450 [ nips/min ]

E 65 / E 75

E 62 / E 72

E 61

E 60 H

E 7/6

E 7/5

C• A•P•D

productionrange

optimum

performance

C• A•P•D

200 225 250 275 300 325 350 375 400 425 450 [ nips/min ]

E 65 / E 75

E 62 / E 72

E 61

E 60 H

E 7/6

E 7/5

C• A•P•D

productionrange

optimum

performance

C• A•P•D

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1.2.1. Machine characteristics of E61, E62, and E72

Element Characteristics

Batt weight Up to 80 ktex. (1125 g/yard).

Nips /min. E 61 - up to 325 nips/min,E62 and E 72 up to 400 nips/min.Maximum speed depends upon the cotton quality and the yarn requirements.

Feeding Forward or reverse.

Quality Maintains very good quality even when the noil percentage is 2 – 4% less thanconventional.

Batt feed rollers Larger diameter giving a more secure batt supply.

Feed roller plateIdeal cradle form:No change of position during feeding.

Nipping line distance Shortened for better fibre guiding and control.

Fibre nipping actionThe nipper is formed to produce double nipping lines. This produces a secureand uniform fibre control.

Nipper movement During the combing action the nipper moves concentrically around the circularcomb, maintaining a constant distance.

Circular combdiameter

125.4 mm diameter, which is 20% smaller than other combers. This means thatthe circumferential speed Vu is less and the combing action is gentler.

Top comb The needling is specified according to the cotton

Top detaching rollersPneumatically loaded with uniform load distribution produces good fibre controlas the fringe is withdrawn form the batt. – Less loss of good fibres.

Web collection The web is collected at one side, which is the best distribution of piecing lines.

Drafting unitRobust with two clearly separated draft zones, belt driven easy to set and has a

low maintenance factor.

ROBOlap(E 72 only)

Fully automatic piecing of the laps. Controlled preparation of the ends of thelaps to be joined. Improved quality of sliver at lap piecing.

Lap weight Up to 25 kg depending upon the cotton being processed.

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2.1. Introduction

Depending on the needs of the customers, combing enables finer higher quality yarns to be spun. Or lower-gradecotton can be used whilst maintaining the required yarn quality.

This also applies to the running conditions at the subsequent process stages all the way to the finished textileproduct.The spinning mill is therefore in a position to choose the solution that is most economical in comparison withcarded yarn.

2.2. Benefits of combing

The benefits of combing, i.e. of the textile product and its processing properties, can be outlined as follows:

2.2.1. Extraction of short fibres

greater yarn evenness

finer yarns can be spun higher strength reduced hairiness improved spinning characteristics improved processing all the way to the finished textile product uniform fabric appearance

2.2.2. Extraction of impurities

reduction of trash particles and seed coat fragments reduction of neps and thick places

more even dye absorption uniform fabric appearance

Since combing improves the spinning characteristics and the process-ability throughout the subsequentprocesses, it has a considerable influence on the economics of the production.The comb-out has to be performed as efficiently as possible because it also has a decisive influence on theeconomy of the production.

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2.3. Fibre selectivity

The fibre selectivity is an important criterion for assessing the separation of short and long fibres in the combingprocess.

A good fibre selectivity is distinguished by the following characteristics: optimal separation of short and long fibres optimal utilization of raw material and therefore better yarn quality cost saving through a reduction of the noil percentage while maintaining the required yarn quality consistent yarn quality

There are different possibilities of assessing the fibre selection. The simplest method is the comparison of thefibre length measurements of combed slivers and noils.

2.3.1. Fibre length distribution in combed slivers and noils

The new generation of combers, in comparison with older generations as well as with other combers available onthe market, show a considerably better fibre selectivity with the same noil percentage.

The following diagrams compare a modern comber with a conventional comber processing with the same noilpercentage. With the modern comber there are more long fibres in the combed sliver and fewer long fibres in thenoil.

Fibre length distribution in a combed sliver E 7/6 (E 60) at 350 rpmin comparison with E 7/4 at 240 rpm

Cotton 1 5/32”, noil 15%

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Fibre length distribution in the noil E 7/6 (E 60) at 350 rpm incomparison with E 7/4 at 240 rpm

Cotton 1 5/32”, noil 15%

Any long fibres in the noil are equivalent to a loss of raw material. Experience shows that with optimal fibreselectivity, the noil can be reduced by up to 2% while maintaining the same yarn quality.

2.4. Factors influencing the combing result

For good combing, the following parameters are important: combing preparation circular comb top comb nippers feeding drafting

2.4.1. Circular comb

2.4.1.1. Circular comb dimensions

In comparison with the other comber manufacturers, the circumferential speed of the Rieter circular combs, as aresult of the smaller diameter, is about 20% lower with the same nipping speed. Higher circumferential speedsresult in higher forces on the fibre fringe during combing, which can cause long fibres to get into the noil.

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2.4.1.2. Circular comb clothing

Four different types of circular combs, which have been developed to cover the range of cotton staple suitable forcombing. The applications range from short staple cotton all the way to extra-long staple cotton. The choice ofcircular combs depends on the desired noil percentage and the cotton raw material to be processed.

2.4.1.3. Cleanliness of circular combs

The basic requirement for an efficient comb-out is the cleanliness of the circular comb clothing. The needlegeometry and the needle surface also have a decisive influence.

Application range according to noil percentage and staple length detachingsegment (Ec) 7 to 11

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Circular combs, which have a tendency to soiling, have a negative effect on the combing and yarn quality. Roughsurfaces and sharp edges on the needles tend to load much more than smooth round needles. See fig. 7 and 8.

Needle surface of circular combs:

Nitto Rieter (Graf)

2.4.1.4. Service life of circular combs

A few years back, the service life of circular combs was approx. 7 years. Production increases at the comberhave resulted in a higher production throughput. It would therefore be appropriate to relate the service life to theproduction throughput rather than to the production time. The production throughput attained with today's modernhigh-performance combers is approx. 1000 tons per comber (8 heads) depending upon raw material.

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2.4.2. Top comb

The cleanliness of the top comb, like the cleanness of the circular comb, has a decisive influence on the quality ofthe fibre assembly. Numerous trials with air-cleaned top combs have shown that, in comparison with today'sstandard top combs, no improvement has been attained with respect to cleanness. For that reason, Rieter doesnot use air-cleaned top combs on their combers.

2.4.3. Nippers

The nipper geometry for short and long-staple material has been optimized with respect to fibre guiding byreducing the clamping line distance.

Rieter with short clamping line distance:Others Rieter

This has a positive effect on the fibre selectivity and ultimately results in a higher yarn quality. Additionally thenipper profile has been designed to give a double clamping action, which securely holds the batt withoutdamaging the fibres.

Double clamping line for better batt retaining:

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High quality with nippers E 7/6 (E 60)

Cotton 1 1/8”, yarn Nm 100 / Ne60

2.4.4. Feeding

The selection of the feeding time, i.e. forward or reverse feeding, covers the entire noil percentage range from 7to over 20%.

Reverse feeding

Forward feedingVisual model of the comb-out:

The comb-out includes all fibres shorter than the DS

The larger the FD, the more fibres get into thecombed sliver, i.e. the lower the comb-out.

All the fibres which are longer than the DS-FD getinto the combed sliver.

DS = detachment setting (ecartement)FD = feed distance

During the return motion, the feed distance FD is

added to the DS.

The comb-out includes all fibres shorter than theDS+FD

The larger the FD the higher the comb-out.

All the fibres which are longer than the DS get intothe combed sliver.

The nipping of the batt by means of the feed roller plate additionally results in a better distribution of the forces,

which has a positive effect on the retaining capacity of the fibres in the batt and therefore on the quality of thecombed sliver.

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2.4.5. Synchronization of movements

The coordinated interaction of the elements involved in the combing process has a considerable influence on thefibre selection and the purity of the combed sliver. One important parameter, for example, is the distance betweennipper and circular comb during the combing action. During the entire combing process, the fibre fringe shouldthereby be guided as close as possible to the circular comb.Further, a more precise combing action is achieved by a concentric movement of the nipper with the circularcomb.

Only concentric nipper motion guarantees optimum comber precision.

Others Rieter (concentric nipper motion)

The following diagram shows the circular comb/nipper distance of a Rieter comber and combers of othermanufacturers.

Nipper distance of the circular comb Distance without material.

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2.5. Yarn quality

Taking all these influencing factors into consideration, and assuming the same noil percentage, the qualityattained with Rieter machines is clearly better than that of other manufacturers.

Rieter combing in comparison with othersRing yarn Ne 38, T/” = 24.4, cotton 1 1/16” to 1 1/8”, fibre fineness 4.3 mic.

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2.6. Automation

Automatic lap piecing makes a contribution to the quality assurance as well as to the efficiency of the combingsection. The comber E 70 R, which is equipped with ROBOlap, guarantees constant and good sliver evenness,independent of the skills of the operating personnel.

Combed sliver with manual iecin

Combed sliver

Combed sliver with ROBOla

CVm = 6.42%

CVm = 4.11%

CVm = 3.34%

Especially if the mill is not equipped with an autoleveller Drawframe after the comber, inferior manual lap piecingcan lead to count variations in the yarn and consequently to bar formation in the woven or knitted fabric. Thequality of the lap piecing procedure strongly depends on the personnel. With the aid of the ROBOlap, a constantand optimal evenness of the combed sliver can be attained during the lap piecing procedure.

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The time required for a manual piecing procedure also depends to a great extent on the personnel. Waiting timesfor the changing procedure at the comber are difficult to assess and have a considerable influence on the long-

term efficiency of the combing section.

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3. Machine Elements

3.1. Combing elements

The following diagram shows the arrangement of the combing elements.

Nipper motion

Nipper control

Nipper

Piecing distance

Detaching motion

Circular comb

S = feed rollerRK = circular comb

F = top combV = web guideP = cleaning roller A = top detaching rollerR = detaching rollerLP = LP-Bridge (Lap Prevention)W = delivery rollerT = table trumpetK = table calender roller

The even load distribution between (R) the bottom detaching rollers (grooved steel) and (A) the topdetaching rollers (rubber cots) ensures defined detaching of the fibres.

A continuous web guide (V) guarantees an optimum support of the web even with short-staple raw material. With the delivery rollers (W) and the position of the table trumpet (T), the web extraction is strongly

eccentric. This results in an even distribution of the piecing line in the sliver. The LP-Bridge (LP = Lap Prevention) eliminates the electrostatic charging of the web and thus avoids

lapping at the top detaching rollers. The table trumpet (T) and the maintenance-free table calender rollers (K) condense the web to provide a

sliver suitable for the transport to the drafting unit.

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3.2. Combing action and machine settings

The sequence of operations of the comber can be seen from the following series of diagrams.

3.2.1. Batt feed (backwards)

The feed rollers “S” move thebatt “W” forward in steps of4 to 6.6 mm while the nippersZo and Zu are open.

3.2.2. Nipping

The upper nipper is lowered ontothe cushion plate “Zu” to clamp thefibres

3.2.3. Rotary combing.

The combing segment “K” sweeps its saw – teeth orneedles through the fibre fringe ”B” and removesanything not held by the nippers.

During this action the nippers move concentrically andmaintain a constant combing distance.

3.2.4. Nippers forward movement.

The nippers open and move towards the detachingrollers “A”.

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3.2.5. Web return.

During the forward movement of the nippers, thedetaching rollers “A” have reversed rotation andreturned part of the web “V” which was previouslywithdrawn. The returned portion of the web protrudesfrom the back of the detaching rollers.

3.2.6. Piecing.

The forward movement of the nippers carries theprojecting fibre fringe “B” to the returned web “V” to besubsequently gripped by the detaching rollers to makea piecing.

3.2.7. Detaching.

The detaching rollers begin to rotate in the forwarddirection and draw the leading fibres out of the batt“W”. The batt is securely held by the feed rollers “S”.

3.2.8. Combing by the top comb

Before the start of the detaching operation, the topcomb “F” is lowered into the fibre fringe. As the fibres are drawn out by the detaching rollers,the trailing part of the fringe is “combed” as it passesthrough the top comb.

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3.2.9. End of cycle

The nipper assembly is retracted and the top comb israised in preparation for the next combing cycle.

3.2.10. Removing noil from the circular comb

The circular comb rotates continuously and inthe lower position the combing segment passesa revolving brush. The high-speed brush cleansthe combing segment of fibres and impurities and ejectsthem into an aspirator that conveys the noil to a collectingdrum.

3.3. Nipper feed rate

The nipper feed rate controls the amount of batt fed each cycle of the comber. Increasing the distance increasesthe production rate but decreases the degree of combing, especially with regard to the cleanliness of the web.

The feed rate can be set to be: 5.9 mm / 5.2 mm / 4.7 mm / 4.3 mm per comber cycle.

3.3.1. Type of feed

The intermittent feed is performed by a ratchet arrangement that turns the feed roller according to the movementof the nipper. Changing the ratchet position cause the feed to be performed either during the forward movement

or the backward movement of the nipper.The impact of feed direction is:

3.3.1.1. Forward feedThe batt is advanced during the forward movement of the nipper. The newly fed portion will be first broughttoward the detaching rollers before being subjected to the action of the circular comb. Consequently, some“uncombed’ fibres will be taken through the machine.Noil percentage is relatively low.

3.3.1.2. Backward feedThe batt is advanced during the backward movement of the nipper. The newly fed portion will be first brought tothe circular comb before being moved toward the detaching rollers. In this way, all fibres are subjected to the

combing action.Noil percentage is relatively high.

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3.4. Detachment setting (Ecartment)

The detachment setting adjusts the distance between the nipper and the detaching roller at their closest point.This setting influences the noil percentage.

Wider settings result in increased noil and vice-versa. The minimum detaching distance is 16 mm and produces the lowest levels of noil. The maximum detaching distance is 23 mm and produces the highest level of noil.

3.5. Circular comb

Circular combs are normally equipped with a saw tooth type covering. Older machines used pin-type combs.

There are basically two different versions of combs employed today: A 90˚ wire covering has been in use primarily for short to medium staple length cotton up to 1 1/8″. The 90˚

primacomb 5014 is mostly used for a noil extraction of 10 to 19%. A recent development for high speed combing has been the C.A.P.D. optimized primacomb 7015 for cotton

up to 1 1/2″ and for noil extraction of 14 to 22%. A 111˚ wire covering, Primacomb 5015 is used for longer staples and higher noil extraction.

The combs are intensively cleaned at 30-minute intervals by reducing the speed of the machine to a slow speedfor a few seconds while the clearer brush remains in high speed.

The setting of the circular comb should be done according to the operating instructions.

3.6. Top combs

The top combs consist of a single row of needles (26 or 30 needles per cm) that comb the back fringe of thedetached web.

The deeper the penetration of the top comb, the cleaner the combed sliver will be. The noil level will also beincreased.

The short fibres and trash restrained by the top comb are primarily retained in the remaining batt fringe andthen combed out by the next action of the circular comb.

With an increased top comb penetration or with a higher number of needles/cm, the top comb tends to fill upwith trash particles and short fibres. →More frequent cleaning of the top comb is required.

The cleaning of the top comb is important in maintaining the quality of the combing action. It is notappropriate to increase the intensity of the top comb and reduce the necessary time between comb cleaningcycles if the operators cannot perform the task in a timely manner. The top comb cleaning cycle should notbe less than every four hours. (The maximum cleaning cycle should be at least eight hours to maintain goodrunning conditions)

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3.7. Piecing

The individual fibre fringes that are pulled out of the batt by the detaching rollers must overlap in order to form acontinuous web.

The degree of overlapping is controlled by adjusting the timing control disc. (Following the machineoperating instructions)

The overlap is a very common source of sliver and yarn irregularity and has to be carefully set. Care has to be taken to not create a combed sliver that has thin places associated with the piecings. These

create weak sliver which stretches out in the creel of the roving frame and cause yarn count variation orcreel breaks.

With the use of the RSB Drawframe after combing, it is sometimes preferable to produce a somewhat heavyoverlap to produce stronger sliver. The thick piecings can then be corrected by the autolevelling action. Thissolution should be used only after it has been found that good piecings produce weak sliver. This situation

frequently applies to the processing of short staple cotton. The quality of the piecing should be judged by considering the spectrogram and CV% value of the evenness

tester. Piecing spectrogram peaks occur at the wavelength corresponding to the piecing wave x the draft. I.e. 35

mm x 12 (draft) = WL of 42 cm.

3.7.1. Index disk – Setting the overlap

With the Index disk the detaching timing can be altered to cause the fibres to be laid more or less over each

other.

The index disk is graduated from –1 to +2. For short staple cotton a typical setting could be +0.5 whereas for longstaple cotton it could be 0.0 or even a negative number

Piecing overlaptwo index disk settings

More overlap

Less overlap

To optimize the overlap, spectrograms of several small adjustments of the index disc are needed to find the bestset up. As can be seen from the following, piecing peaks and humps can be seen on both sides of the best indexdisk setting.

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3.7.2. Spectrograms of piecings

Optimizing the spectrogram by adjusting the index disk.

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3.8. Table funnel

The combed web is gathered to one side to distribute the piecings. The sliver is compacted as it is pulled throughthe table funnel. This action should not disturb the piecings but must impart some additional strength to facilitateeffective transportation to the drafting zone.

Typical funnel application is 5.5 mm

3.9. Drafting

The eight combed slivers have to be pulled to the drafting zone with a minimum of tension. The table should be

well cleaned and not resist the sliding of the slivers.The drafting zone distances have to be set according to the cotton staple length.

The draft depends upon the batt weight, the noil percentage removed and the required weight of the deliveredsliver.

3.9.1. Roller settings

The break draft zone roller distance is fixed and cannot be adjusted.

The main draft zone steel roller distance is adjustable between 31mm and 50 mm. Because of the top rollarrangement, the actual nip point distance (ratch) is from 41mm to 60 mm.The roller setting has to be optimized by testing to find the best condition. It is suggested that the rollers shouldbe progressively closed until the lowest evenness CV% is found and then increased slightly until the CV% isincreased by 0.2 to 0.3%.

NOTE: With the rollers set for the lowest CV% they are so close as to break the longest fibres and this has anegative influence on spinning performance and yarn quality.

The following may be used as a guideline for nip point (Ratch) settings

Staple diagram from Main draft nipping distance (Ratch)Zellweger Fmax. (longest fibre)

Almeter 1% staple length plus 2 to 3 mm

Fibro - Graph 2.5% staple length plus 9 to 10 mm

Minimum distance = 41mm

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3.9.2. Draft distribution

The break draft can be set at - 1.14 or 1.36 or 1.5.The normal break draft is 1.5 but the others are occasionally used depending upon the fibres being processed.

The total draft range can be set from 8.6 up to 19.6 in 5% increments.The main draft is dependent upon the total draft and the break draft.

Main draft = Total draftBreak draft

3.10. Coiling

The coiling of combed sliver is very important for the running performance of the downstream processes. Thefollowing points should be observed: The sliver should not be disturbed in any way. The condenser (trumpet) must be selected to be compatible with the combed sliver weight and bulk. Follow

the machine recommendations. The sliver should be sufficiently compressed to impart sliver cohesion toallow it to pass through the creel of the finisher Drawframe.

The stepped delivery rolls must be correctly set and not trap, cut or otherwise damage the sliver. The coiler plate should be suitable for the sliver weight being delivered. The can and base plate should be positioned so that the sliver column is clear of the sides of the can. There should be a clearance of 8 to 10 mm between the inside of the can and the sliver column at full can

condition. The layering of the coils should be set to facilitate a uniform can filling and unrestricted sliver removal.

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4. Recommendations

4.1. Start up steps

The start up procedure requires that the machine be initially set according to the operating instructions and thenoptimized to obtain the needed degree of combing.

4.1.1. Raw material

There are three groups of combing operations:

4.1.1.1. Long staple combing

This process uses first grade long staple cotton, 1 ¼″ and longer, to produce fine to very fine yarn of topquality. Noil extraction is usually high and up to 25%.

4.1.1.2. Medium staple combing

This process uses medium length cotton of 1 1/8 ″ to 1 7/32 ″ staple. A wide range of noil from 12 to

18% is removed depending upon the yarns to be spun.

4.1.1.3. Short staple combing

Short staple combing uses the cotton that is normally used for carded yarn production to improve yarnstrength and smoothness. The noil extraction is relatively low, in the range 6 to 12%. This process isalso used when extra cleaning or extra fibre separation is needed in subsequent spinning operationssuch as high draft Vortex spinning.

4.1.2. Machine condition

The most critical areas of the comber are: sharpness and cleanliness of the circular combs, correctly buffed detaching rollers with the optimal roller pressure, the top combs must be clean and not damaged, cleanliness of the nippers, web-pans and noil ducts is very important, the vacuum system must function correctly.

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4.2. Recommended procedure for change of noil %

The following table has been prepared as a systematic approach to checking and setting the comber when achange of noil percentage is required in a plant.

Choose a comber to be initially used and CHECK the NOIL percentage being removed to be sure that it isfunctioning consistent with the plant performance. Be sure that the noil collection can be performed reliably.

Check list for the change of noil percentage

Always refer to the manual E 60 E62

1 Measure the actual NOIL percentage 2/18 2A/19

2 Position the nippers at exactly INDEX 24 2/10 2A/10

3 Flip open the TOP DETACHING ROLLS 2/11 2A/22

4 Take out the TOP COMBS & loosen the HOLDER 3B/19 3B/20

5Check the distance “d” between NIPPER and DETACHING ROLLS withfeeler gauge (for reference) 3B/17 3B/18

6 Change the setting of the ECARTEMENT 3B/17 3B/19

7 Check the distance “d” again as in step # 5 3B/17 3B/18

8 Set the FLEECE GUIDE (feed plate) 3B/16 3B/17

9 Set the TOP COMB PENETRATION 3B/20 3B/21

10 Set the TOP COMBS 3B/19 3B/20

11 START THE COMBER 2/7 2A/9

12 Measure the NOIL PERCENTAGE 2/18 2A/19

13 Set the PIECING 3B/24 3B/23

14 Check the diameter of all 8 TABLE FUNNELS 3A/24 3A/25

15 Decide upon the FEED SYSTEM – forward /backward 3A/13 3A/13

16 Is the FEED AMOUNT acceptable? 3A/11 3A/11

17 Install the correct FEED CHANGE GEAR 3A/9 3A/818 Adjust the DRAFTING ZONE according to Staple EB/6 3B/5

19 Set the SLIVER MONITOR 3C/29 3C/28

20 Check the CAN FILLING 5C/9 5B/9

21 Check the YARN-Q-PARAMETER Lab Lab

22 Check and Re-Set the other machines accordingly

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4.3. Impact of preceding processes

4.3.1. Bale laydown, blowroom

The consistency of the fibre blend is of paramount importance in the combed yarn spinning plant. Variationsin short fibre content can directly create variations in noil removal, which can lead to combed sliver weightvariation.

The bale laydown should be carefully controlled to create consistent mixing of fibre characteristics at thebale feeding operation.

Waste bales should be avoided when fine, high quality yarns are to be spun. Part bales left over from a previous laydown SHOULD NOT be laid on top of a new laydown. The part bales

should be packed between bales. The moisture content of cotton influences the fibre strength. Fibre, which has low moisture content at the

bale laydown and in the blowroom, is going to be damaged. This increases the short fibre content in the cardsliver and this will increase the noil percentage. Increasing the cotton moisture content has to be carefully controlled to optimize fibre strength without

creating “sticky” cotton that causes choking and lapping in the fibre handling system. Problems of fibre tagging or rolling in the transportation pipes result in increased entangled fibres, neps,

damaged fibres and short fibres in the comber laps. Chokes in any of the feeding chute or machines causes a deterioration of the cotton.

4.3.2. Carding

The card, when set and operated correctly, greatly improves the quality and condition of the fibre in process.

On the other hand, cards with damaged wire, bad surfaces, or incorrect settings create off quality sliver. Theproblem is amplified if there is channelling of stock behind the Drawframe and to the UNIlap.

It should be realized that, in many instances, when the card is set to maximize one function there is acorresponding negative aspect. Such “pro and cons” are:

For a clean yarn – maximize trash removal ► Increases short fibre content► Increases the noil %.► Reduces elasticity.

Maximize nep removal – Closer setting ► Increases short fibre content.►

Increases the noil %. Maximize fibre and yarn strength – Preserve the staple length, Do not “Overwork” the fibre,

Do not use a close setting of the feed plate.Use somewhat open flat settings.If TREXplus is used, set it to minimize fibre damage. Production should be minimized within reason.Try to use lighter sliver weight, but it may be limited by the doubling, draft and batt weight requirements of thesystem.

► Most of these actions will increase the nep and trash level in the card sliver and lap.

Increasing the carding production rate will normally increase fibre damage. To minimize fibre damage

the settings should be opened slightly.► This increases the nep and trash levels.

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4.4. Lap formation

4.4.1. Lap splitting

The lap should not split at the comber. Causes could be: Lap winding tension not uniform, - Avoid lap weight drift. Lap winding contact pressure is too high at that part of the lap build. Lap winding contact pressure is too low at that point of the lap build. The lap is too hairy. (See next paragraph regarding causes). The winding speed could be too high. - (Maximum speed of 120 m/min for long staple cotton and 90 m/min

for medium staple cotton). Some times the laps tends to split for a while when the new laps are started. They may be too large in

diameter. Check by producing some slightly smaller diameter laps.

4.4.2. Laps hairiness

The laps should not be hairy, causing layers to cling when unwinding. The machine functions that have most influence on lap hairiness, in order of impact are: Total draft between card and lap winding should be limited depending upon the cotton staple length.

Recommended total draft

Pre drawing – 5 to 6 ends up UNIlap – 22 to 28 ends up

Draft of 5 to 6 Draft of 1.5 to 1.6

Total draft

7 to 8 8 to 9 9 to 10

Shorter cotton Medium cotton Long cotton

High short fibre content of the lap. Pressure on the lap during winding can be too high or too low. UNIlap winding speed may be too high, (dependent upon staple length)


4.5.1. Waste / noil collection

The circular comb with the noil is cleaned by the rotating brush. The noil is subsequently sucked away to thedrum fibre separator where it is collected as a loose sheet. A pressure sensor controls the movement of the drum separator to ensure that sufficient air suction is applied tothe cleaning brushes.

The pressure control switch should be adjusted to produce a noil sheet thickness of 30 to 40 mm.

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As a guideline there should be a vacuum in the suction duct of:

14 to 16 mm (w.g.) for long staple cottons15 to 18 mm (w.g.) for short staple cottons.

The suction supplied to the machine should be 25 mm (w.g.)

VERY IMPORTANT: The suction system removing the noil from the circular comb has to function correctly,otherwise the combing action will be compromised and inferior quality sliver will be produced.


For cotton to process satisfactorily at high speed through lap preparation and combing, the room air shouldcontain 8 to 10 g of water / kg of air.Realizing that there can be considerable climatic swings throughout the year the following chart shows therecommended air conditions.

Same climatic conditions should be maintained in preparation and combing.Recommendation:

HumidityTemperature° Celsius Relative % Absolute g/kg

Standard value 24° 50-52 8-12Short-term (month) +/- 2° +/- 3Fluctuation

range Long-term (year) 22° - 28° 45 – 55

Note: A higher tendency to sticking of the raw material requires a lower absolute humidity.

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5. Troubleshooting

If the comber is not performing as expected and no obvious problems can be seen, then it is necessary to set themachine with a basic “default” setting.

5.1. Basic setting

Top comb ± 0.0Feeding 5.2 forward

Detaching distance 7.0Index disk 0Break draft 1.5Total draft 13Minimize batt tension (Reduce until loose then increase one step)Minimize table tension (Reduce until loose then increase slightly)

Run and, if possible, produce sufficient combed sliver to test for noil %, evenness and spectrogram. If there areobvious problems address them according to the instruction manual.

5.2. Reduce neps in the sliver

Check the nep level in the sliver from two or three cans from the machine in question. Check the nep level in the laps on the machine Calculate the actual removal rate.

Nep removal rate % = Neps in lap - Neps in sliver x 100 %Neps in lap

50 percent nep removal is standard practice. To remove more neps requires special components,settings and a high percentage of noil removal.

To increase a current nep removal efficiency:- increase the noil percentage- increase the top comb penetration- check the effect of the backward feeding (Backward feeding is a more intensive combing action).

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5.3. Reduce the short fibre content in the sliver

Check the short fibre content (SFC) in the sliver and in the laps. Determine the percentage of short fibres removed.

Short fibre removed % = Lap SFC% - Sliver SFC% x 100 %Lap SFC%

Check the condition of the circular combs. If they are worn or loaded the comber will loose its efficiency. Check the noil to see if it has an excessive amount of long fibre. If there is long fibre in the noil, determine why the fibre selectivity is not as it should be. The batt weight may be too light and not being held securely by the nippers. Check the cotton fineness and determine the number of fibres in the cross-section of the lap. (500,000 is

the target)

The slivers in the batt may be misplaced creating unevenness across the fleece. Check the feed and increase the feed length. – 4.3 mm can result in excessive combing and possible

fibre damage.

4.7 or 5.2 mm feed will reduce the noil percent, increase the production rate but reduce the combing intensity.

NOTE : Backward / Forward feed:

With forward feed, increasing the feed ► Reduces the noil removal.

With backward feed, increasing the feed ► Increases the noil removed

5.4. Mean Time Between Assists (MTBA)

The comber efficiency is best judged by considering the running performance alone and excluding the interruptiontime and operator waiting time.

Some of the factors that interfere with running performance fall into the following categories.

5.4.1. Table funnel stops

The usual causes are: choke, fleece break top roll lap, top comb overloading irregular feed, lap tagging feed Plate – roller slip or batt jamming, contaminated web plates and web guides.

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5.4.2. Machine cleanliness

Sticky deposits create a problem If possible, reduce the humidity at the comber and lower the moisture content throughout the processing line. Cotton wax accumulation. Some cotton types have a very waxy surface that can collect on contact points. The components have to be cleaned frequently to minimize machine stops. The deposit of wax is influenced

by aggressive actions removing the wax from the fibre surface. The cleaning machines, cards and combersshould be operated in the least aggressive manner.

5.4.3. Lapping of the detaching rollers

The following are causes of lapping around the detaching rollers: top rollers not buffed or treated correctly, wrong type of cot, no L.P. bridge, sudden swings of room conditions temperature / humidity, sticky cotton.

5.5. Cloudy fleece

By a visual examination it is possible to see if the fleece is uniform and regular. When the fleece has a “cloudy”appearance, the machine is not functioning correctly.The possible causes are:

the feed rollers may not be meshing correctly, the feed roller ratchet not correctly aligned, irregular feed at the feed plate, loading of the circular comb, loading of the top comb, low pressure of the detaching roller, top detaching roller too small in diameter, sticky Detaching roller, incorrect setting of the Index disk. batt weight too heavy for the nippers to have adequate control,

faulty suction system not removing the noil correctly.

5.6. Recommendation to remove a low noil content from long staple cotton

As cost saving measure, it is sometimes necessary to remove the least amount of noil from long staple cotton.This presents a problem of high fibre withdrawal forces that can be excessive and create a poor quality combedsliver.

The reasons for the difficulties are: To reduce the noil % the nipper is set closer to the detaching rollers (Ecartement).

The fibre withdrawal forces are increased and can reach a critical level. The fibres are not withdrawn uniformly and the fleece is cloudy and may even have holes in it.

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This produces an uneven sliver and a yarn with increased imperfections of thick places, thin places and

neps. OPTIMIZATION. Preferred action

REDUCING the batt weight to lower the number of fibres in the lap cross-section will reduce the fibrewithdrawal forces and improve the combing quality.

The negative side of this is that the productivity of the lap winder and comber is proportionally reduced.

Second choice

Use the same Lap weight,

reduce the nipper speed,

reduce the detaching roller speed,this reduces the fibre acceleration and lowers the work on the fibres,there is less fibre slippage at the detaching rollers,

Result - Acceptable quality but reduced production rate.

Short term solution (Not preferred)

Increase the pressure on the detaching rollers by a moderate amount. (Say 4.2 to max 5.0) - (A greaterincrease could be problematic.)The increase in roller pressure will more securely pull the fibres from the nippers, but any slight changesin batt condition or room conditions will cause a problem.

With this solution the productivity is not lost, but

The combing quality is compromised

The lifetime of the cots will be drastically reduced and the quality will deteriorate within a few days.

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8. Roving


1.1. Introduction 2

1.1.1. Features of roving production 3



3.1.

Creel 5 3.2. Drafting 5

3.2.1. Condensers 6

3.3. Drafting system 7

3.3.1. Break draft 8

3.3.2. Total draft recommendations 8

3.3.3. Cradle spacer plates 8

3.3.3.1. Cradle opening 9

3.3.3.2. Guideline for spacer plates – Cradle openings 9

3.4. Twist crowns 10

3.5. Roving twist 10

3.5.1. Twist level for roving production 10

3.5.2.

Roving twist level for spinning 11

3.5.3. Suggested roving twist curves 11

3.5.4. Manual strength test of roving 12

3.6. Flyer speed 12

3.7. Roving tension 13

3.7.1. Checking the roving tension (Roving stretching) 14


4.1. Air requirements 15

4.1.1. Exhaust air / Suction 15

4.1.2. Room conditioning 15


5.1. Introduction 16

5.2. Creel 16

5.3. Draft zone 16

5.4. Delivery rolls to package 16

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1.1. Introduction

Sliver from the Drawframe is fed as a single strand to the drafting zone of the roving frame. One sliver can issupplied for each of the roving positions. There is no doubling of ends behind the drafting zone. The sliver isattenuated in length by the draft and the mass / unit length is reduced by the draft.

A typical draft of the roving frame can be 8.4 which means that a sliver of 70 grains/ yd (5 g/m) would be draftedinto a roving of 70/8.4 = 8.33grains/yd or Ne1.0 (0.6 g/m

Sliver Draft Delivery Count

70 gr /yd 8.33 8.4 gr/yd Ne 1.0

5 g /m 8.33 0.6 g/m Nm 1.69

4915 tex 8.33 590 tex

The twist is inserted in the roving as it is wound onto the bobbin by the flyer. The twist level is the speed of theflyer divided by the delivery speed.

There are two systems of specifying the twist: Turns / unit length i.e. turns per inch (tpi) or turns per meter (t/m). Twist Multiplier (TM), which is the factor used to calculate the twist (tpi) for a given range of roving size or

fibre type.

Twist (tpi) = TM x √Roving count Ne or (hank)Twist t/m = α m x √Roving count Nm

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1.1.1. Features of roving production

The performance of the roving frame is measured in terms of “how well can the spinning machine produce yarn.For the spinning machine to effectively spin high quality yarn at high speeds the roving must be compatible withthe overall system and as close as possible to being fault free.Each phase of roving production has to be correctly optimized, set and maintained to ensure roving consistency.

Key:Head stock Feeding creel TailstockDrafting drive Drafting system Suction systemInverter flyer and bobbin drive Twisting and winding

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To be added later

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3. Machine Elements

3.1. Creel

The sliver fed to the roving frame is normally in the weight range of 50 to 80 grains/yd (3.5 to 5.6 g/m).Sliver weights heavier than 80 gr/yd can create problems of excessive fibre bulk in the double apron draftingsystem.For fine count spinning, the sliver should not be less than 50 gr/yd because fine sliver is fragile and can stretch inthe creel causing count variation.

To assist in the feeding of the sliver a power driven creel is recommended to lift the sliver from the cans andminimize sliver tension.

3.2. Drafting

The draft zone of the roving frame is a three over three double apron system. The features are:

2

Drafting arrangement

1

The sliver (1) is drawn in by the feed rolls of the drafting system, passes through a break draft zone and thenenters the main draft zone that includes a double apron arrangement to control the fibres.

The drafted fibres are twisted into roving (2) as they emerge from the front rollers.The bottom rollers are fluted and the top rollers are covered with synthetic rubber cots.

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3.2.1. Condensers

Condensers are provided to guide the fibres as they flow through the drafting system. The arrangement is asfollows:

123

Condensers

1 Feed condenser,2 Middle condenser,3 Delivery condenser.

The sizes of the condensers have to be selected according to the fibres being processed and the bulk thematerial passing through the draft zone.The choice is important in that it affects the roving quality and the running performance of the machine.Condensers that are too small can lead to fibre accumulations and uncontrolled stretching.Condensers that are too large loose control of the fibres and result in a deterioration of the roving evenness(CV%).

The condenser widths are colour coded for easy identification. There is a greater variation in the deliverycondensers as the range of roving size is considerable.

The widths of the delivery condensers range from: 17 mm for roving Ne 0.5 (Nm0.8 or 1200 tex) to 6 mm for roving Ne 2.0 to 3.5 (Nm 3.0 to 6.0 or 300 to 200 tex)

The standard condenser settings are shown in the table below,

Standard condenser sizes and colours

sliver feed weight Ne 0.16 to 0.12Nm 0.27 to 0.22tex 3600 to 4900

52 to 70 gr/yd

Ne 0.12 to 0.10Nm 0.20 to 0.17

Tex 4900 to 590070 to 80 gr/yd

Position Opening Colour Opening Colour

Feed 12 mm Black 14 mm Red

Middle 10 mm Grey 12 mm White

Delivery 10 mm Beige 12 mm White

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3.3. Drafting system

The arrangement and distance settings of the drafting system are shown in the following diagram.

Standard settings for the drafting system

Setting 1 2 3

Raw material:For cotton,synthetics and

blends up to 40 mm

For longest cotton,synthetics and blends

up to 50 mm

For synthetics andblends up to 60 mm

A = Cradle length 34,5 mm 45,0 mm 60,5 mm

B = Guide bar 24,0 mm 33,0 mm 48,0 mm

C = Main draft distance bottom rolls 49,0 mm 69,0 mm 76,0 mm

D = Break draft distance bottom rolls min. 60,0 mm min. 60,0 mm min. 70,0 mm

E = Main draft distance top rolls 55,0 mm 66,0 mm 82,0 mm

F = Break draft distance top rolls min. 59,0 mm min. 59,0 mm min. 70,0 mm

G = Forward offset 1st top roll* 4,0 mm 4,0 mm 4,0 mm

H = Backward offset 2nd top roll 2,0 mm 2,0 mm 2,0 mm

J = Backward offset 3rd top roll 0,0 mm 0,0 mm 0,0 mm

Note: The condenser width must be matched with the sliver and roving size. Similarly, the correct apron spacers must be selected by a series of tests. The standard settings for the break draft distance:

(D) = Longest fibres + 31 mm for easy to draft fibres and (+ 33 mm or +35 mm for fibres resistant to drafting).

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3.3.1. Break draft

The break draft can be varied between 1.02 and 2.04; however, it is recommended that it be kept as low aspossible. High break drafts require higher drafting forces and this can create associated vibrations in the feed rolls and

middle rolls. Higher break drafts tend to create roving irregularities such as slubs and thick and thin places. The power

required in the break draft action can overload the drafting rolls extending over the length of the machine. For optimal roving uniformity it may be necessary to limit the sliver weight to enable the break draft zone to

function correctly. With synthetic fibres up to 40 mm staple with draft resisting characteristics the break draft may have to be as

low as 1.022or 1.063 to prevent roll vibrations.

3.3.2. Total draft recommendations

The mechanical limits of the total draft are 4 to 20. The recommended draft ranges for different fibres arepresented below.

The draft ranges are divided into five basic groups dependent upon the raw material:

Recommended total draft range

Fibre type Preferred draft Possible range

Short staple cotton <1 1/16″ 6 to 9 5 to 10

Medium staplecarded cotton 1 3/32″ combed cotton up to 1 3/16″

7 to 12 6 to 14

Long staplecombed cotton 1 1/4″ to 1 7/8″

9 to 18 8 to 18

Blends of cotton/ syntheticsand man made fibres

7.5 to 12.5 7 to 13

100% synthetic fibres (polyester, viscose,acrylic, and nylon) up to 60 mm length

8 to 14 7.5 to 17

Note: When processing synthetics or blends the total draft should not be less than 7.5. When processing synthetic fibres the sliver weight must be adjusted so that the number of fibres in the sliver

should not exceed 25,000.

3.3.3. Cradle spacer plates

The roll setting and the cradle opening distance at the nose affect the fibre control with the double apron draftingsystem. The smaller the cradle opening the more the apron restrains the fibres. It is necessary to find the

optimum opening for roving quality and running performance.

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Spacer plates3.3.3.1. Cradle opening

The cradle opening “X” affects the fibre control in themain draft zone.Advantage of reducing the cradle opening is to improvethe uniformity of the roving.Disadvantages of reducing the cradle opening are: Worse running behaviour of the roving frame. Drafting problems at sliver splicings Increased slubs created by an “over control” of

fibres. Increased susceptibility to changes of climatic

variations. Increased susceptibility to changes of blend level.

Increased sensitivity to changes of: Key: + fibre finish 1 = Cradle+ fibre length and 2 = Spacer plate+ fibre fineness 3 = Deflection rail

X =Cradle opening (thickness)

It is recommended that the cradle opening “X” be increased slightly from that of the lowest CV%. An increase inCV% of 0.2 to 0.4% is often preferred because of the overall improved performance.

The benefits are: Better running behaviour of the roving frame Better running performance of the spinning machine Up to 30% fewer end- breaks No discernable loss of yarn evenness Better IPI values in the yarn

3.3.3.2. Guideline for spacer plates – Cradle openings

Roving Count

Ne Nm Tex

Cradle

Opening “X”

To 1.0 To 1.7 To 590 8.5 mm

1.1 to 1.8 1.8 to 3.0 590 to 300 6.5 mm

1.8 to 2.5 3.0 to 4.2 330 to 200 6.5 mm

Over 2.5 Over 4.2 Under 220 4.5 mm

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Technology Handbook

3.4. Twist crowns

The actual twist level in roving is not sufficient to gather the fibres as they emerge from the drafting zone. Tosupplement the twist, a “false twisting” device is provided at the top of the Flyer to temporarily create twistbetween the flyer and the delivery rolls. This false twist does not pass beyond the top of the flyer.

These false twisting devices are referred to as “Twist Crowns” (grommets). The roving rolling over the surface ofthe twist crown generates the false twist. In addition to the false twist aiding in the collection the fibres at thedelivery rolls it imparts strength to the fibre strand enabling it to travel from the delivery roll to the flyer top.

There are several types of twist crowns, composed of different materials, number of notches and shapes. TheRieter standard twist crown is with 12 notches.

The diameter of the hole through which the roving passes has to be selected according to the fibres being

processed.

Raw material Hole diameter (mm)

Combed cotton Ø 8 mm

Carded cotton and blends Ø 10 mmSynthetic fibres Ø 13 mm

3.5. Roving twist

Twist is required in roving to provide strength to enable it to be wound onto a package. The roving strength is alsoneeded to allow the roving to be pulled from the creel to the drafting system of the spinning machine. It is veryimportant that the twist level be optimized for: the running performance of the flyer, the roving stability in the spinning creel, most importantly, for the drafting characteristics on the spinning machine.

3.5.1. Twist level for roving production

As mentioned above, the roving requires twist to gather the fibres at the delivery roll and to provide rovingstrength so that it can be wound onto the bobbin. Additionally, the roving is subjected to high levels of centrifugalforce during the bobbin build, which tend to cause the outer layers to burst if there are localized weak places.The twist level CAN NOT be arbitrarily increased to prevent layers bursting because the roving has to be draft-able at spinning.Until the optimal twist has been established it is suggested that any tendency of bursting layers be resolved byreducing the flyer speed, particularly as the bobbin builds up.

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3.5.2. Roving twist level for spinning

Some twist is helpful in the spinning process because it causes the fibres to be slightly compacted and lie withinthe fibre bundle. The twist imparts a resistance to drafting that is desirable but only up to a point. If the draftingresistance is high, the roving frame will not be able to draft the bundle in a controlled manner.

The problems of high roving twist are: the roving will not draft in the break draft zone un-drafted roving will be pulled through the system and called “Hard Ends” hard ends cause ends down ends down at the roving frame can be a major operational problem

When one end comes down, the whole machine stops. If the machine does not stop quickly at an end down, theflying waste brings down several adjacent ends.

3.5.3. Suggested roving twist curves

The following is a chart showing the actual twist levels in turns per inch and turns per meter for roving of varioussizes and of different materials.

Key:12 Cotton13 Synthetic fibres21 = Roving twist

Roving twist

22 = Roving count

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How to read the twist chart:Find the roving count on the base and follow the vertical line up to the appropriate fibre curve. Then follow the

horizontal line to the left where the suggested twist is shown.

3.5.4. Manual strength test of roving

A traditional test for roving strength has proven to be helpful when a material is changed and the frictional /cohesive forces are not known.

It is essential that roving should not be produced that cannot be drafted in spinning. The following test can beconducted to find the degree of roving twist and determine whether it is appropriate as a starting point.

The manual test is conducted as follows:Manual Strength Test

1. Stand the full roving package (1) on a flat surface(2), the base of the bobbin being at the top.

2. Take the roving from the lower portion of the build(3), grip it and pull slowly in the direction causing thebobbin to turn.

3. Stop pulling after approximately 5 inches (12 cm)and then continue to pull again. Do not release thegrip on the roving. Repeat the procedure every 5inches until the roving breaks.

4. Eventually the roving will break at position (4).Measure the total length of roving unwound betweenpositions (3) and (4). The length indicates thestrength of the roving.

5. Repeat at least five times to obtain an average breaking length.6. The following is an interpretation of the various lengths.

Distance of 3 to 4 Assessment:

300 to 500 mm = Soft roving twist,500 to 800 mm = Normal roving twist,800 to 1100 mm = Hard roving twist

Over 1100 mm = Roving twist is too high and cannotbe drafted on the spinning frame.

3.6. Flyer speed

The flyer speed and the twist level determine the delivery speed of the roving frame.The maximum speed of the front bottom roller is 50 m/min.

The flyer speed, which relates to bobbin speed, can be higher at small bobbin diameters than it can be at larger

diameters. The centrifugal forces increase as the bobbin diameter increases. The bobbin speed is frequentlylimited to prevent the roving layers bursting as the bobbin build.

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To maximize the productivity, the flyer is driven by an inverter drive to vary the flyer speed.Highest speed at small bobbin diameter.

Reduced speed at full bobbin diameter.The range of flyer speeds is dependent upon the fibres being processed and the roving strength that isdetermined by the twist level.

The following chart shows the normal twist levels and the suggested upper / lower speed ranges for five differenttypes of materials.

Flyer speeds, raw materials and twist coefficients.

Key:6 = Short staple – carded cotton 1 1/167 = Medium staple – carded cotton 1 3/32

– combed cotton 1 3/32 to 1 3/168 = Long staple – combed cotton 1 ¼ to 1 7/89 = Blends –cotton / synthetics and blends of man made fibres,10 = 100% synthetic fibres, – polyester, viscose, acrylic.11 = Flyer speed

NOTE:

Optimal flyer speeds can only be determined by tests in the spinning plant.

3.7. Roving tension

The roving has to be precisely wound onto the bobbin. Each wrap should be laid along side the previous coil. The vertical movement of the bobbin controls the spacing between the coils. The amount of roving required to make one wrap

+ on the empty bobbin is 168 mm,+ at the full bobbin is 478 mm with a 6″ flyer

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The speed of the vertical movement of the bobbin has to be incrementally reduced as the package diameterincreases.

The roving is wound onto the bobbin at a surface speed corresponding to the delivery speed of the draftingsystem, (up to 50 m/min)

The difference in bobbin surface speed m/min and the flyer press finger surface speed m/min is the rovingtake-up speed in m/min.

The take up speed in m/min remains constant throughout the build, but the difference between the flyer rpmand the bobbin rpm has to change as the bobbin diameter increases.

The setting of the controls of the bobbin speed is critical to the winding of the roving. Attention: If the speed differential is not correct throughout the build the winding tension will vary. Variation in winding tension results in roving size variation.

High tension stretches the roving and reduces the roving size. Low tension can create problems of loose rovingbetween the delivery rolls and the flyer.

When a change is made in the roving size or material, the setting of the build and the winding tension has tobe performed.

It is necessary to check the size of the roving

3.7.1. Checking the roving tension (Roving stretching)

It is necessary to remove a consistent length of roving from different layers throughout the bobbin and comparethe weights.

The larger the sample length the more reliable will be the result. For this reason it is suggested that the samplesize should be the length of roving wound as the first layer onto the bare bobbin.

The weights of the samples should be plotted to reveal weight changes resulting from the roving being stretch.

It should be recognized that roving weight variations could also occur as a result of sliver weight variations andshould be taken into account when considering roving stretch.

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4. Recommendations


4.1.1. Exhaust air / Suction

To be added later.

4.1.2. Room conditioning

The temperature and relative humidity should be controlled to within +/- 2% of the norm. For most materials thefollowing applies:

Raw material Temperature Relative humidity

Cotton 28 ° Celsius (82˚ Fahrenheit) 48 %

Synthetic fibres and blends 28 ° Celsius (82˚ Fahrenheit) 43 %

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Technology Handbook

5. Troubleshooting

5.1. Introduction

As with all textile machines, there are certain aspects that have to be taken care of to maintain an efficientperformance of the roving frame.

As mentioned previously, any single cause of an end to come down means that production is lost at all positions.

Target should be less than one stop per doff .

5.2. Creel

Absolute minimal sliver breaks in the supply cans. One doff of the roving frame may produce 850 lb ofroving which is the equivalent 15 to 30 cans of drawing depending upon the can size.

Splicings of sliver can cause an end down in the draft zone. Sliver spliced in the creel should becontrolled to high standards. The splicing should be able to pass through the draft zone. Additionally, thesplicing should not be thin, otherwise the break will occur between the delivery rolls and the bobbin.

There should be no “piece cans” fed to the roving frame. There are too many splicings. The sliver should be correctly coiled in the cans, be clear of the can walls and with no tagging layers. There should be no “crossed” ends in the creel. Slivers should not touch each other as they move

through the machine.

5.3. Draft zone

The sliver condensers should be of the correct size, The drafts and roll settings should be optimized. The top roller condition and pressure should be correct. All surfaces and rolls should be clean and well maintained, especially the drafting aprons.

5.4. Delivery rolls to package

The roving twist, winding tension and package build must be correct. The flyer twist crowns (grommets) should be of the appropriate diameter and not wobbling on the flyer. There should be zero surface breaks on the bobbin. The roving tension between the delivery rolls and the crowns should not be too high. There should be a

slight bow in the roving path to the front flyers.

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Technology Handbook

9. Ring Spinning


1.1. Introduction 4 1.2. Principle features 4 1.2.1. Advantages of the ring spinning machine G 33 5 1.2.1.1. Ri-Q-Draft with the Ri-Q-Bridge 5 1.2.1.2. FLEXIdraft 5 1.2.1.3. ROBOdoff 5 1.2.1.4. SERVOgrip 5 1.2.1.5. INTERcool 6 1.2.1.6. SERVOdisc 6 1.2.1.7. ROBOload 6


2.1. Bobbin changing program 7 2.1.1. Basic function of SERVOgrip 7 2.1.2. Sequence of doffing operations 9


3.1. Creel 10

3.2.

Roving Guide –Trumpet 10

3.3. Drafting Zone 11 3.3.1. Categories of fibres for ring spinning 12 3.3.2. Application ranges for cradles 12 3.3.3. Settings of the drafting rollers 13 3.3.3.1. Bottom steel roll settings 13 3.3.4. Draft Range 14 3.3.4.1. Draft and roving sizes for cotton types 14 3.3.4.2. Draft and roving sizes for synthetic / blends 15 3.3.5. Break Draft 16 3.3.5.1. Break draft range for various materials 17 3.3.6. Cradle apron spacers 17

3.3.7. Drafting guide arm 18 3.3.7.1. Guide arm loading 19 3.3.8. Top roll cots 20 3.3.8.1. Top roller cots for ring spinning machine G 33 21 3.3.8.2. Top roller cots for ComforSpin® machine K 44 23 3.3.8.3. New drafting system load 24 3.3.8.4. Cot buffing intervals 24 3.3.9. Aprons 25 3.3.9.1. Top Aprons 25 3.3.9.2. Bottom Aprons 25 3.4. Twisting zone 26 3.5. Spinning balloon 26

3.6. Ring and traveller systems 27 3.6.1. Ring classification 27

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3.6.1.1. Ring Diameters 28 3.6.2. Traveller speeds 29

3.6.2.1. Traveller form 30 3.6.2.2. Traveller applications 31 3.6.2.3. Traveller weight 33 3.6.2.4. Estimation of wear and tear of the ring and traveller 33 3.7. Balloon control ring 35 3.8. Bobbin build 35


4.1. Start-up suggestions 37 4.2. Illustrations of Starter Windings 38 4.3. Recommendations for downstream processing 38

4.3.1. Knitting 39 4.3.2. Weaving 40 4.4. Center-P+ Electronic centring device for spindles 41 4.4.1. General 41 4.4.2. Directions for Use 41 4.4.3. Exchanging the centring adapter 43 4.4.4. Maintenance 44 4.4.5. Charging the battery 44 4.5. How precise must the „ring centring“ be? 45 4.5.1. Centring methods 45 4.5.1.1. Goal 45 4.5.2. Results from experience 45 4.5.2.1. Yarn hairiness depending on the centring accuracy 46 4.5.2.2. Yarn hairiness of the extreme spinning positions 47 4.5.2.3. Yarn hairiness within 10 Spinning positions 48 4.5.2.4. Yarn quality depending on the accuracy of centring 48 4.5.2.5. Yarn hairiness depending on the yarn tension 49 4.5.3. Centring device „RES“ 50 4.5.4. Centring device „CenterP+“ 50 4.5.4.1. Requirement specifications from 2000 50 4.5.4.2. Practical application 51 4.5.4.3. Complaints 51 4.5.4.4. Comparison measurements 52

4.5.4.5.

The gradations 53

4.5.4.6. The comparative measurements 53 4.5.4.7. Position of CenterP+ 55 4.5.5. How precise must the ring centring realy be? 55 4.5.5.1. Accuracy of centring 56 4.6. Air requirements 57 4.6.8. Exhaust air / Suction 57 4.6.9. Room Conditions 57


5.6. Break Draft Zone 58

5.6.8. Roll settings too close 58 5.6.9. Roll setting too open 58

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Technology Handbook

5.6.11. Break draft too high 58 5.7. Main Draft Zone 58

5.7.8. Settings 58 5.7.9. Synthetic Bottom Aprons 59 5.7.9.3. Leather Bottom Aprons 59 5.7.10. Top Aprons 60 5.7.11. Positioning of the Bottom and Top Aprons. 60 5.7.12. Bottom Apron Replacement 60 5.8. Guide Arm Pressure 60 5.8.8. Cradle Pin Settings 60 5.9. Spinning speed curve 61 5.9.8. Start up Speed 61 5.9.9. Bottom Speed 61 5.9.10. Top Speed 62

5.10. Bobbin Diameter 62 5.10.8. Bobbin Base Shape 62 5.11. Spin Out Speed 62 5.11.8. Factors affecting the automatic setting of the Spin Out Speed 63 5.12. Top Bunch Formation 63 5.13. Ring Rail Lowering 63 5.14. Back Windings on the Bobbin 63 5.15. Spindle Brake (Inverter Drive) 64 5.16. Twist Reduction / Increase to Improve Doffing and Start of Spinning 64 5.16.8. Twist Change Function 65 5.17. Clamping of the Yarn 65 5.18. Yarn Length between Clamp and Traveller 65 5.19. Sequence of start up after doff 66 5.19.8. Pre-Turn of the Spindles 66 5.19.9. Snarl Elimination 66 5.19.10. Start Spinning 66 5.20. Optimization of the doffing process 67 5.20.8. Prior to doffing, when the yellow light is on and the travelling cleaner is parked 67 5.20.9. During the Stopping Action 67 5.20.10. During the Doffing Action 67 5.20.11. After Start of Spinning 67

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Technology Handbook

1. GENERAL INFORMATION

1.1. Introduction

Ring spinning has been in existence since its introduction by an American, John Thorpe in 1828 and then Jenksdeveloped the traveller that rotated on the ring. These two steps opened the door to our current ring spinningtechnology that is the standard of yarn manufacture. Other spinning technologies have been developed that arehigher in productivity, but are lacking in many aspects of the yarns desirable characteristics.

Ring spun yarn has retained its position as the system that produces the strongest, finest, softest and mostlustrous yarn and fabric.Rieter has led the way in ring spinning machines, but it is only when the machines are optimally used and

maintained that the full benefits can be realized.

To spin high quality yarn at high spindle speeds the fibre and its preparation have to be controlled to highstandards. The ring frame cannot spin superior yarn from inferior material or roving.


Ring spinning machine G 33

For purposes of this chapter, the features of theG33 ring frame will be used to represent the state

of the art of modern ring spinning.

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Technology Handbook

1.2.1. Advantages of the ring spinning machine G 33

The advantages of the G 33 are:

1.2.1.1. Ri-Q-Draft with the Ri-Q-Bridge+ High constant long-term yarn quality+ drafts up to 80 fold /technological)+ high-precision bottom rollers+ central pressure control, automatic pressure relief, no periodic yarn defects+ Ri-Q-Bridge for improved yarn quality due to absolutely precise fibre guidance

1.2.1.2. FLEXIdraft

This facilitates the high performance of the drafting system on long machines:+ drive concept with separate drive for bottom rollers and spindles+ fast and easy adjustment of main draft and yarn twist+ higher precision of adjustments thanks to electronic settings at the panel+ no need to change gears+ no mechanical work necessary+ lower noise emission+ fully maintenance-free+ stable long term quality+ reduced torsional vibrations

1.2.1.3. ROBOdoffThe high speed doffing system:+ fully automated bobbin removal device+ fully integrated monitoring of the doffing process+ central doffer drive in centre of machine+ machine down time < 2 min+ lower end breakages at restart after doffing+ higher machine efficiency

1.2.1.4. SERVOgrip

Is a unique technique to clamp the yarn at the doff to prevent underwinding on the spindle:+ no more underwinding+ substantially reduced fibre fly+ less yarn defects and end downs+ less maintenance+ essential yarn savings

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Technology Handbook

1.2.1.5. INTERcoolHas been developed to effectively cool the components of the machine and minimize heat being

emitted into the spinning room:+ all motors and frequency converters are adapted to the integrated liquid cooling system+ longer service life of components+ low susceptibility to faults due to low operating temperature+ lower energy consumption+ no filter cleaning, maintenance-free

1.2.1.6. SERVOdiscCop transfer system+ automatic conveyance of full cops

+ open rail system+ cops disc individually interchangeable

1.2.1.7. ROBOload+ Tube loader system+ flexible economical alternative

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Technology Handbook

2. TECHNOLOGICAL FUNCTIONS

2.1. Bobbin changing program

The SERVOgrip system makes it possible to automatically change bobbins and minimize the problemsassociated with automatic doffing and start up.

There are no yarn underwindings on the spindle, Machine contamination is minimized. There should be no uncontrolled yarn remaining after the bobbins have

been doffed. The yarn break should occur close to the yarn clamp.

2.1.1. Basic function of SERVOgrip

All spindle types are equipped with the SERVOgrip system (underwinding free doffing).

Yarn Twist Reduction during back winding

- bobbin is full - SERVOgrip is opened - ring rail moves- top-buch completed - approx. 40 mm of upwards andring rail moves downwards spinning thread is SERVOgrip is closed

inserted - spinning thread is- delivery stops clamped

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Technology Handbook

Doffing

4. 5. 6.4. 5. 6.

- bobbin is removed by - new tube is fitted - ring rail straightens snarlROBOdoff - spinning process is

started (no remainingthread)

After the bobbin is filled with yarn, the yarn twist must be reduced during the backwinding process, especially withsynthetic fibres such as Polyester with high fibre strength and with coarse yarn counts. This is to reduce the yarnstrength during the doffing sequence.

The following example is to demonstrate the extremely high forces, which build during the yarn separation atdoffing without twist reduction.

Fibre strength polyester 55 cN/texFibre substance utilization 70 %Yarn count polyester Ne 20 (30 tex)Number of spinning positions 1200Correction factor, since not all threads will break simultaneously 70 %

N textexcN AV 97007.0*1200*30*7.0*/55 ==

These high forces would create unnecessary stress on the mechanical components of the doffing system andcould lead to problems. Modern drive systems enable us to reduce the yarn twist during the backwinding to anoptimal level of yarn breaking strength.With this technology in place, yarns with very high breaking strength and elongation, in combination with a highnumber of spinning positions can be doffed automatically without problems.By reducing the yarn twist during the backwinding process, the separation point in the yarn can be better defined.The cone winder can find the yarn end at a higher rate of success and therefore, function at a higher operatingefficiency.

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2.1.2. Sequence of doffing operations

Travelling cleaner parked.

The travelling cleaner must be parked prior to the start of the doffing cycle. Set (menu 12.5) to 2-5 minutesdepending upon the machine length yarn count and type of cleaner.

Schematic Diagram of the SERVOgrip bobbin change program.

12.1(1)

12.1(2)

4 1 . 2

( 2 )

1 2 . 8

( 2 )

4 1 . 2

( 1 )

1 2 . 7

( 1 )

12.5 (2)

12.6 (1)

12.6 (2)

12.5 (1)

12.8 (3)12.9 (1)

12.9 (2)

12.7 (3)

1 2 . 7

( 2 )

12.5 (3)

13.3 (2)

* *

* 13.4 (3)

13.3 (1)

1 3 . 4

( 1 )

12.4 (1)

12.3

12.4 (2)

1 2 . 2

( 1 ) 12.2 (2)

100% [11.5 (1)]

11.3 (1) 11.4 (1)

1 1 . 5

( 2 )

1 1 . 5

( 3 )

9 5 %

13.3 (1)

11.6 (2)

11.4 (2)

D o f f i n g c y c l e

Ring rail movement

Spindle rpm

Delivery speed

0.9 x RD

1 1 . 5

( 3 )

11.3 (2) 11.3 (2)11.4 (3)

12.2 (2) M a c h i n e s t o p

13.5

S p i n d l e + F e e d - / M i d d l e - r o l l e r

D e l i v e r y - r o l l e r

XX.X (X) = Data picture (Line)

Key: For doffing cycle Key: For starting cycle

12.5(3) Cops Change RR Position, 12.2(1) Start spindle in RR position,12.6 Top Bunch Position, 12.2(2) Start spindle after cop change12.7 Back Windings on the Bobbin, RR upward / downward12.7(2) Length of nipping thread, Clamped length, 12.3(2) Snarl lift reversal point12.7(3) Opening distance of the Clamp, 12.4(1) Snarl lift RR speed - Upwards12.9(2) Ring rail position Brake Spindle Motor, 12.4(2) Snarl lift RR speed - Downwards13.3 Spin Out Speed Adjustment. 13.4(2) Pre-turn spindles yes/no13.3(2) Wait Time, RR pos. 0 to Spindle Stop13.4(1) Yarn Twist Adjustment during spin out,13.4(3) Wait for Spindle Stop at RR-pos. 0.

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3. MACHINE ELEMENTS

3.1. Creel

The creel arrangement can affect the machine performance in many ways. It may appear that the creel is simplya way to conveniently suspend roving bobbins over the drafting system.The creel is the starting point of the spinning operation.In order to maximize the weight of the roving in the creel, the bobbin holders and roving guides have to beprecisely located to prevent abrasion of the roving as it moves to the drafting system.

The critical points are:

The Roving must not rub or cross other roving.Roving creel

When bobbins of 165 mm diameter are to be hung ina creel with five rows it is important that the creel beloaded evenly with half full bobbins

The roving guide bars must be located at the correct height. If the barsare of differing heights, the tension in the roving varies and this can leadto count variation in the yarn.

Creel vibration is a sign that some component is out of balance. The creeltends to amplify vibrations from the lower part of the machine.

Creel vibrations accentuate the tendency of the roving to stretch in its

path to the drafting zone. This can lead to yarn irregularities and countvariation. The bobbin holders and bobbin brakes, if used, should be clean and function

correctly. Roving tension in the creel should be as uniform as possible.

3.2. Roving Guide –Trumpet

The roving guide is mounted on the roving traverse bar located behind the drafting system. The bar moves slowlyto feed the roving over an extended area to spread the wear of the components and hence, extend the lifetime ofthe cots and aprons.The traverse motion should be set to cover as much of the surface as possible, but limiting the movement toensure that the fibres do not get too close to edges.

The trumpet surfaces must be smooth with low friction. They should not scuff the roving.

The guiding width of the trumpet should be large enough to allow free passage of the roving. They should notcreate resistance or chokes that lead to: increased yarn hairiness stretching of the roving and subsequent yarn count variation spinning ends down.

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3.3. Drafting Zone

The components of the drafting system are shown below.

Drafting system components

The drafting system is fundamentally important in that it basically determines the uniformity of the yarn. The draftat spinning is higher than any other draft applied throughout the process and it handles the fibre mass when it isat its finest. This necessitates the precise control of the fibres being processed to suppress the formation ofdrafting waves.In roller drafting the fibres are accelerated as they pass from the control of the first pair of rollers to the secondpair of rollers running at a higher surface speed.The short fibres are released from the first rollers and “float” until they are accelerated by the second rollers oraccelerated by longer adjacent fibres already being drawn at the higher speed.

The control of the short fibres is the primary challenge of the high performance drafting system and has beengreatly improved by the development of the “Double Apron” drafting system for the main draft zone. The twoaprons restrain the short fibres until they are close to the nip of the delivery rolls.

Drafting waves appear as variations in mass and can be clearly seen in the knitted or woven fabric. They also arerecognizable in the spectrogram as waves with an average wavelength of approximately 2 1/2 times the mean

fibre length. The Ri-Q-Draft system with the Ri-Q-Bridge has been developed to enable the aprons to moreprecisely control the fibres and consequently enable higher drafts to be used without loosing fibre control.It should be emphasized that all elements of the drafting system are critical to the production of consistent highquality yarn.

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3.3.1. Categories of fibres for ring spinning

The range of raw material processed on the ring-spinning machine can be classified under the following mainheadings according to commercial standards:

Short staple - cotton < 1 1/16″ - carded, Medium staple - cotton 1 1/16″ – 1 3/32 ″, carded,

“ “ cotton 1 1/16″ – 1 ¼ ″ combed, Long staple - cotton 1 ¼″ - 1 7/8 ″ combed, Blends – cotton /synthetics,

assorted synthetics, 100% Synthetic fibres up to 60 mm staple length – polyester, viscose, acrylic, nylon,

To optimally control the above-mentioned fibre groups, different cradle types / length are available (R2P 36, R2P

43, and R2P 59).

The weighting arm (guide arm) FS 160 P3-1 is used for all of the cradle lengths.

Key: A = cradle length1 = Spacer2 = Spacer thickness

3.3.2. Application ranges for cradles

The cradle length “A” is determined by the material tobe spun and the fibre length. The nipping point distance

in the main draft zone must be greater than the longestFibres. The range of application of the various cradle lengthsare shown in the following table.

Cradle type 100% Cotton Blends 100% Synthetics

R2P 36 Up to commercial staple 1 ¼”carded and combed

Cotton up to commercialstaple 1 ¼” with Synthetics up

to 40 mm

Staple length up to 40 mm

R2P 43 From commercial staple 1 ¼” Cotton up to commercialstaple 1 ¼” with Synthetics

from 44 mm

Staple length from 44 mm

R2P 43+ ----- Synthetics blends up to 50/51mm

Staple length from 51 mm(main drafting dist. 54 mm)

R2P 59 ----- Synthetic blends up to 50 mm Staple length from 50 to 60mm

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3.3.3. Settings of the drafting rollers

The bottom steel rollers (1, 2 and 3) are of 27 mm andlie with their centres in the same plane.

The back top roller (7) has a synthetic rubber cot of 30mm and is set slightly behind the back bottom rollerwith a backward offset (13) of 1.0 to 3.0 mmdepending upon fibres.

The middle top roll /Cradle roller (6) is set with a slightbackward offset (11) of 1.0 to 2.5 mm depending uponthe fibres.

The front top roller (5) has a synthetic rubber cot of30 mm and normally has a forward offset (9) of 6.5mm.

The distance between the rear bottom roller (3) andthemiddle bottom roller (2) is referred to as the breakdraftdistance (15).

The distance between the middle bottom roller and thebottom delivery roller is referred to as the main draft distance (14).

Measurements of the distances between the top rollers should be made when the rollers are loaded at 2.2barpressure.

The normal clearance between the nose of the apron and the front top roller is 0.5 to 1.0 mm. In the eventthat 32 mm top rollers are used, the cradle should be moved back by 0.5 to 1.0 mm.

3.3.3.1. Bottom steel roll settings

The machines are pre set during manufacture according to the materials specified by the customer.The cradle length establishes the main draft zone distance. The break draft zone setting is dependent upon thefibre type and roving twist level.

The following chart lists the steel roll settings for different fibres:

Bottom Steel Roller Settings

Fibre Type Cradle length Break Draft Zone Distance Main Draft Zone Distance

Carded cotton <1 1/16″ 36 mm 65 – (70) mm 42.5 mm

Combed cotton medium staple1 1/16″ to 1 7/32 ″

36 mm70 mm draft < 60

65 mm draft 61 - 8042.5 mm

Long staple Combed cotton >1 1/4″ 43 mm70 mm draft < 60

65 mm draft 61 - 8048.0 mm

Blends Cotton / synthetics < 40 mm 36 mm 70 mm 42.5 mm

100% Synthetics < 40 mm 36 mm 70 mm 42.5 mm

100% Synthetics 51 mm 43 mm 70 mm 54.0 mm100% Synthetics 60 mm 59 mm 80 mm 68.0 mm

Drafting Roller Arrangement

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Technology Handbook

In most instances the standard roll settings are acceptable and should not be changed without consultation withthe business unit.

However, in some synthetic fibre spinning plants the materials being processed may contain a large portion offibres exceeding the specified length for the cradle in use, i.e. fibres longer than 40mm with the 36 mm cradle, orfibres longer than 50 mm with the 43 mm cradle. Under these circumstances the middle bottom roll can bemoved backwards up to 8mm to accommodate the increased staple length. Then, the middle top rolls, with thecradles, and the back rollers have to be adjusted accordingly.

3.3.4. Draft Range

With the Ri-Q-Draft double apron drafting system it is possible to achieve optimal yarn quality results with high

drafts. There is a wide draft range potential depending upon the material and the preparation prior to spinning.

Additionally it is necessary to consider the spinning ends down level as part of the optimization process.In practice the reality of the yarn count and the size of the available roving establishes the draft range. Forexample, the count limit of short cotton maybe Ne 30/1 and a practical roving size could be Ne 0.75/1. As a resultthe draft at spinning would be 40, which is well below the mechanical limits.

3.3.4.1. Draft and roving sizes for cotton types

The following chart shows some practical cotton roving size and yarn count relationships.

Yarn and roving sizes for cotton yarns

Key:1 = Roving count (Ne)2 = Carded yarn range3 = Combed yarn range4 = Short staple cotton5 = Medium staple cotton6 = Long staple cotton8 = Yarn count (Ne)

As can be seen, the practical ranges are:

Normal Roving, Yarn and Draft Ranges for Cotton

Roving RangeNe

Count RangeNe

Draft Range

Short Staple Carded 0.5 to 1.5 Up to 30/1 14 to 33

Medium Staple Carded / Combed 0.6 to 1.7 24/1 to 70/1 25 to 80

Long Staple Combed 0.8 to 3.0 60/1 to 150/1 40 to 80

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Technology Handbook

3.3.4.2. Draft and roving sizes for synthetic / blends

Ranges of roving size for synthetic yarns

Key:1 = Roving count (Ne) 9 = 3.3 dtex 60 mm 11 = 1.7 dtex 40 mm8 = Yarn count (Ne) 10 = 2.2 dtex 50 mm 12 = 1.3 dtex 40 mm

13 = 1.0 dtex 38 mm

The draft limitations that apply to synthetics are not related to the short fibre content of the material, as is the casewith cotton. Some man made fibres can be spun well with the moderately high drafts, whereas with other fibretypes the draft range has to be limited.

The following table lists the recommended draft ranges for man made fibres:

Normal Roving, Yarn and Draft Ranges for Man Made Fibres

Roving RangeNe

Count RangeNe

Draft Range

Polyester, 50 to 60 mmstaple

0.6 to 1.2 10/1 to 40/1 14 to 50

Viscose/Polyester 40 mm 0.6 to 1.7 10/1 to 60/1 15 to 65

Fine Fibres of1.0 or 1.3 dtex

0.7 to 2.7 4/1 to 100/1 24 to 60

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3.3.5. Break Draft

Break draft at the spinning frame has the primary function of pre-tensioning the roving so that a consistent form ofroving is presented to the main draft zone.

The forces involved in the break draft zone increase with the level of break draft. If the break draft isincreased it can overload the drive systems on long machines processing fibres with high draft resistance.

The drafting forces also increase when the yarn count is coarser. If the break draft is incrementally increased the drafting force will increase and remain steady until a “critical

draft” is reached at which stage the drafting forces become erratic and drafting is uneven. The break draftshould always be more than 10% below the critical level.

The influence of the break draft on yarn quality is relatively small, but can have a negative effect if the rollsettings are not appropriate.

A general rule is;

1) As the break draft is increased the break draft zone distance should be reduced to maintain yarn quality. The adverse effect is that the drafting forces increase considerably.

2) With lower break drafts the roll settings can be more open. The drafting forces are reduced,

With larger break draft zone distances, the system is less sensitive to variations of fibre length, roving draftresistance and climatic conditions.

Lower break drafts should be retained as long as possible.

NOTE: Rieter always calculates the break draft using the diameter of the middle steel roller and does notinclude the apron thickness.In the event that a customer considers Rieter’s break draft to be low, it may be because they are basing theircalculation on the effective diameter including the apron thickness.

The apron thickness increases the effective steel roller radius by approximately 1 mm, which means thatcalculated draft would be increased accordingly.

In reality, the speed of the apron is slightly lower than the speed of the steel roller because of apron slip. This

means that the actual break draft is slightly lower than the calculated value.

This phenomenon should be minimized as much as possible by the correct selection of aprons and a thoroughmaintenance program.

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3.3.5.1. Break draft range for various materials

The following is a list of the normal break drafts used for different fibres and with total draft levels.

Fibres / Total Draft Range of Break Draft

1.09 1.10 .12 1.14 .16 1.18 1.20 1.24 1.3 1.5Carded cotton /

< 35 draft 1.14 …… .1.18

Combed cotton /< 45 draft46 – 6061 - 80

1.14…… ..1.181.18…...1,22

1.20..1.24

Blends, Cotton andSynthetics /

< 70 draft

1.16…… ……1.22

SyntheticsUp to 40 mm /

< 60 draftLyocell

Cohesive Polyester

1.16…… …1.201.10………..1.14

1.09

SyntheticsUp to 50mm /

< 50 draft1.16....1.18

SyntheticsUp to 60 mm /

< 45 draft1.16....1.18

In some instances it is beneficial to lower the break draft to reduce the thick and thin places that show up inknitted fabrics. It is suggested that knitted samples be evaluated for appearance in addition to the normal labuniformity tests.

3.3.6. Cradle apron spacers

The cradle is supplied with a series of spacers of different thickness that snap onto the cradle holder. Thespacers locate the nose of the top apron relative to the nose of the bottom apron.

The smaller the spacer size, the closer the top and bottom aprons. To optimally control the fibres during drafting

the spacers have to be selected based upon yarn quality and spinning performance.

Key: A = cradle length1 = Spacer 2 = Spacer thickness in mm

Up to a point, thin spacers usually produce yarn of betterIPI and evenness values. However, if the spacers are toothin the restraining forces will be too strong and overcontrol the fibres.

Over control of fibres results in:

Ends down due to ”hard ends”, High thick and thin places, Increased susceptibility to variation in fibre length,

drafting cohesion and climatic conditions.

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For the practical, best performance it is suggested that the preferred spacer should be 0.5 mm thicker than theone giving the lowest yarn CV%. This action may cause a slight increase in the yarn CV%, but there will be a

better overall running condition.

The following chart can be used as a guideline for spacer selection, but optimization is necessary.

Spacer Thickness Depending upon Yarn CountStep-Bridge

Ri-Q-Bridge

Key: 1 = Spacer mm о = Synthetic fibres2 = Improved running conditions X = Cotton carded3 = Improved CV% and IPI values w = Cotton combed.In the case of man-made fibres and carded cotton, a ¼ larger distance piece is recommended.

The factors that influence the effect of the aprons on the fibres being drafted are: Yarn count, - finer yarns need smaller spacers, Fibre length, - longer fibres need larger spacers Fibre cohesiveness, - Combed cotton needs slightly smaller spacers than carded cotton even though the

fibres of combed cotton are normally longer. Some synthetic fibres may need larger spacers.

Key: 4 = Distributor, rear.=

3.3.7. Drafting guide arm

The guide arm is the same for the three cradle lengths(36, 43 and 59 mm). The forward offset of the top deliveryrolls is normally 6.5 mm.

To obtain similar pressure conditions with the threecradles lengths, the pins (A and B) must be correctlylocated.

Prior to machine shipment the pins are inserted in theappropriate holes for the specified cradle.

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Technology Handbook

The following diagrams show the correct pin locations for different cradles and bottom apron guide plates.

36 mm cradle with stepped guide plate.The pins go in holes A1 and B1

36 mm cradle when the break draft distance is 75 mmIf the break draft distance is increased to 75 mm, the pin(A) must be moved into hole (A2)

43 mm cradle with stepped guide plate.

43 mm cradle with stepped guide plate,for synthetic fibres of 50 / 51 mm.

The front distributor has to be moved back one hole toposition (B2/1). The resulting forward offset is 2.5 mm.

59 mm cradle with straight guide plate.

3.3.7.1. Guide arm loading

The guide arms are loaded pneumatically. For fine roving or roving with low twist the pressure to the guide armcan be 2.1 bar. For coarse roving, or for roving with high twist or with of fibres with high draft resistance thepressure is 2.3 bar. If absolutely necessary the pressure can be increased slightly to 2.5 bar but component wearand power usage increases.

NOTE: - In addition to the normal guide arm loading, a pressure-reducing valve is provided to functionautomatically when the machine is standing for a pre-selected time. This reduced pressure ensures that the yarnends are secured, but that the top rolls are not deformed during standstill.

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Technology Handbook

3.3.8. Top roll cots

The type and condition of the top roll cots is extremely important to the spinning plant.In most cases, the cots on the feed rolls are of a relatively hard type of rubber where as, the cots on the deliveryrolls are somewhat softer.

The following observations can be made: The condition of the cots greatly affects the quality of the yarn, The surface of the cots must be able to securely grip the fibres being drafted. The cots should be buffed (ground) when signs of wear appear. Normally the time between buffing varies

between 1,000 and 2,000 hours of operation Smooth or greasy cots do not grip the fibres and cause a deterioration of yarn quality. Softer cots on the delivery rolls result in better fibre control during drafting, but the softer rolls tend to lap

when spinning blends or synthetic fibres.

Recommendations:

Raw material Feed roll cotsShore hardness

Delivery roll cotsShore hardness

Cotton 75 – 80° 65 – 75°

Man-made fibres 65 – 75° 75 – 85°

Blends The cot should be selected on the basis of good quality and minimal lapping tendency.

New features 32 mm cot: Minimum diameter

Since the beginning of 2004 the Ring spinning machines are specified and equipped with top roll cots of 32 mmdiameter. For quality reasons the minimum diameter of these cots is limited to no less then 30 mm. This isespecially important for the delivery cots, where good fibre nipping is very important.With the K44, the nip roller can be ground down to a diameter of 28 mm as previously, as long as this roller is notswitched with the delivery cot.

Ri-Q-CotsRieter will offer its own top roller cots as of January 2005. These coverings are named Ri-Q-Cot and will bespecified as first choice on machine components, unless requested differently by customer.The cot qualities (shore hardness) are used according to present assignment or application.

The following top roller coverings are available:Ri-Q-Cot R 168 68° shore bordeaux

R 170 70° shore dark brownR 174 74° shore moccaR 178 78° shore light greenR 178C 78° shore black cage roller

The last 2 digits in the Ri-Q-Cot specification correspond to the shore hardness of the cot.

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Technology Handbook

3.3.8.1. Top roller cots for ring spinning machine G 33

Recommendation(valid for delivery top roller) Supplier

raw material yarn count

Used for TypeHardness

[°Shore] Colour

100% CO Ne 28 - 160 delivery J-463 63° lavender

Blends (CO/ MMF) Ne 40 - 90

100% MMF Ne 50 - 90 infeed J-490 83° grey

100% CO Ne 20 - 27 (60) delivery J-470 70° green

Blends (CO/ MMF) Ne 30 - 39 (70)

100% MMF Ne 30 - 49 (70) infeed J-490 83° grey

100% CO Ne 10 - 19 (30) delivery J-476 74° blue

Blends (CO/ MMF)

100% MMFNe 18 - 29 (40)

infeed J-490 83° grey

100% CO Ne 5.5 - 9 (16) delivery J-490 83° grey

Blends (CO/ MMF)

100% MMFNe 5.5 - 17 (30)

infeed J-476 74° blue

Accotex

all raw material all yarn counts cradle ME-480 80° black




[°Shore] Colour

delivery HA 67T 67° orange100% CO Ne 36 - 160

infeed HA 74T 74°dark

green

100% CO Ne 24 - 36 (80) delivery HA 65A 68° red


100% MMF Ne 50 - 90 infeed HA 74T 74°dark

green

100% CO Ne 20 - 27 (60) delivery HA 70T 70° dark blue Blends (CO/ MMF) Ne 30 - 44 (90)

100% MMF Ne 36 - 49 (90) infeed HA 74T 74°dark

green

100% CO Ne 14 - 19 (30) delivery HA 74T 74°dark

green


100% MMF Ne 28 - 35 (50) infeed HA 80A 78° green

100% CO Ne 5.5 - 13 (20) delivery HA 80A 78° green

Blends (CO/ MMF) Ne 5.5 - 23 (30)

100% MMF Ne 5.5 - 27 (36) infeed HA 74T 74°dark

green

Huber &Suhner(Berkol)

all raw material all yarn counts cradle HA 80R 78° black

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Technology Handbook




[°Shore] Colour

100% CO Ne (24) 28 - 160 delivery R 168 68° bordeaux


100% MMF Ne 50 - 90 infeed R 174 74° mocca

100% CO Ne 20 - 27 (60) delivery R 170 70°dark

brown


100% MMF Ne 36 - 49 (90) infeed R 174 74° mocca

100% CO Ne 14 - 19 (30) delivery R 174 74° mocca


100% MMF Ne 28 - 35 (50) infeed R 178 78° light green

100% CO Ne 5.5 - 13 (20) delivery R 178 78° light green

Blends (CO/ MMF) Ne 5 .5 - 23 (30)

100% MMF Ne 5.5 - 27 (36) infeed R 174 74° mocca

RieterRi-Q-Cot

all raw material all yarn counts cradle R 178C 78° black

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Technology Handbook

3.3.8.2. Top roller cots for ComforSpin® machine K 44




[°Shore] Colour

delivery J-463 63° lavender

nip roller J-470 70° green100% CO

Ne 50 - 160


100% CO Ne 30 - 49 (80) delivery J-470 70° green

nip roller J-463 63° lavenderBlends (CO/MMF) Ne 50 - 80


100% CO Ne 16 - 29 (40) delivery J-476 74° blue

Blends (CO/MMF) Ne 30 - 49 (60) nip roller J-470 70° green

100% MMF * Ne 30 - 80 infeed J-490 83° grey

delivery J-490 83° grey

100% CO Ne 10 - 15 nip roller J-470 70° green

infeed J-476 74° blue

Accotex

all raw material all yarn counts cradle ME-480 80° black

with 100% MMF finer Ne 49 => delivery roller J-470, nip roller J-476




[°Shore] Colour

delivery HA 65A 68° red

nip roller HA 70T 70° dark blue100% CO Ne 36 - 160

infeed HA 74T 74° dark green

100% CO Ne 28 - 35 (70) delivery HA 70T 70° dark blue

Blends (CO/MMF) nip roller HA 65A 68° red

100% MMF Ne 50 - 80 infeed HA 74T 74° dark green

100% CO Ne 18 - 27 (40) delivery HA 74T 74° dark green

Blends (CO/MMF) nip roller HA 70T 70° dark blue

100% MMFNe 30 - 49 (60)

infeed HA 80A 78° green

delivery HA 80A 78° green

nip roller HA 70T 70° dark blue100% CO Ne 10 - 17

infeed HA 74T 74° dark green

Huber &Suhner(Berkol)

all raw material all yarn counts cradle HA 80R 78° black

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[°Shore] Colour

delivery R 168 68° bordeaux

nip roller R 170 70° dark brown

100% CO Ne 36 - 160

infeed R 174 74° mocca

100% CO Ne 28 - 35 (70) delivery R 170 70° dark brown

Blends (CO/MMF) nip roller R 168 68° bordeaux

100% MMFNe 50 - 80


100% CO Ne 18 - 27 (40) delivery R 174 74° mocca

Blends (CO/MMF) nip roller R 170 70° dark brown 100% MMF

Ne 30 - 49 (60)infeed R 178 78° light green

delivery R 178 78° light green

nip roller R 170 70° dark brown100% CO Ne 10 - 17


RieterRi-Q-Cot

all raw material all yarn counts cradle R 178C 78° black

3.3.8.3. New drafting system load

With the larger top roll diameter of 32 mm, an improved flexing action and surface arae between top- and bottomrolls, is adchieved. This results in better fibre nipping and allows a slightly reduced drafting system load.In most instances the lower value of the setting rage can be selected.New: G33 2.1 bar (range 2.1 to 2.3 bar)

K44 2.4 bar (range 2.4 to 2.7 bar)

3.3.8.4. Cot buffing intervals

New cots must be buffed after an initial period of between 500 and 1,000 running hours. The delivery roll cots should be buffed when signs of wear appear which is depends upon the hardness ofthe cot. Normal intervals between buffing are:

Shore hardness Buffing interval

60 – 70° after 1’000 – 1’500 running hours

71 – 75 after 1’500 – 2’000 running hours

75 - 85 after 2’000 – 2’500 running hours.

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When the buffing interval is less than 2,000 hours, the diameter of the cot should be ground down by 0.2mm.

When the buffing interval exceeds 2,000 hours, the cot diameter should be ground down by 0.3 mm toensure that the “glassy layer” has been removed completely.

The feed roll buffing interval can be up to four times longer than that of the delivery roll cots. The Cots on the cradle rolls must never be buffed.

With the new top roll cots 32 mm it is necessary to remove at least 0.3 mm in diameter with each buffing cycle. Ifthis amount is not adhered to, inadequate quality can occur over the service live of the cot. It is alsorecommended, that new cots are buffed (levelled) before the first time use.The grinding instruction of ATPG, advises a surface roughness of 0.8 – 1.0 µm, which should be checkedregularly with a calibrated measuring instrument.

3.3.9. Aprons

The control of the aprons is critical for good drafting. The surfaces of the aprons have to be clean and allow the fibres to draft consistently. If the aprons become

contaminated they should be removed and cleaned. The aprons must be of the appropriate length so as to be at the correct operating tension. They should not

be loose and buckle, nor should they be overly tight and difficult to turn. The bottom apron-tensioning device should be smooth and offer the minimum amount of resistance to the

apron movement.

3.3.9.1. Top Aprons

The commonly used top aprons have the following specifications:

Supplier Cradle Description Diameter x Width x Thickness (mm)

Armstrong 36 NO 7821 39.2 x 30 x 1.1

Armstrong 43 NO 7821 43.3 x 30 x 1.1

DAYtex 36 NB 726 39.25 x 30 x 1.1

DAYtex 43 NB 726 43.3 x 30 x 1.1

DAYtex 59 NB 726 52.8 x 30 x 1.1

3.3.9.2. Bottom Aprons

For cotton and blends of cotton, most commonly leather aprons are used to achieve higher yarn quality.Coated leather aprons, type Torna Grey, are supplied by Sueddeutsche Textilleder (STL). The specifications are:

Cradle length Length (mm) Width (mm) Thickness (mm)

36 235 30 0.9

43 235 30 0.959 260 30 0.9

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Technology Handbook

With synthetic yarns, the rubber apron has a superior wear cycles. Rubber bottom aprons have the following specifications.

Supplier Description Diameter(mm)

Width(mm)

Thickness(mm)

Cradle length(mm)

Recommended use

Accotex 78210 72.5 30 1.1 36 coarser than Ne 36

Accotex 78210 72.5 30 1.1 43 coarser than Ne 36

Accotex 78210 82.0 30 1.1 59 general

DAY 726 NB 72.6 30 1.1 36 coarser than Ne 36

DAY 726 NB 76.2 30 1.1 43 coarser than Ne 36

DAY 726 NB 82.0 30 1.1 59 general

Damaged aprons should be replaced immediately to prevent the production of sub-quality yarn.

3.4. Twisting zone

The twisting and winding zones are common, in that the rotating bobbin inserts the twist and the travellersimultaneously winds the yarn onto the bobbin. For practical purposes, one rotation of the traveler inserts oneturn of twist.

The twist generated in the balloon passes through the pigtail up to the delivery rollers. The twist travels to thepoint of the “spinning triangle” where the fibres emerge from the delivery rolls.

The width of the spinning triangle is established by the width of the fibre strand leaving the rolls. The distance tothe apex of the spinning triangle is influenced by the spinning geometry and the twist level.

3.5. Spinning balloon

The spinning balloon is generated by the centrifugal forceson the yarn as it rotates. The factors influencing the balloonshape include:

The spindle/ bobbin speed:

Higher spindle speeds increase the forces in theballoon.

The length of the balloon: As the ring rail moves up and down the bobbin theballoon height and form change.

The yarn count:The yarn tensions increase with coarser yarns andthe travellers have to be changed accordingly

the traveller:

The weight of the traveller has to selected to balancethe balloon forces and stabilize the balloon form.

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Technology Handbook

3.6. Ring and traveller systems

Historically there have been two types of ring, the horizontal (T-flange) ring for short staple spinning and thevertical ring for spinning and twisting long staple, coarse counts, The vertical rings were frequently lubricated toenable the heavy travellers to run at higher speeds without “burning out”.Over the years the forms of the rings have evolved into those of our present types.

The following is an overview of the ring types3.6.1. Ring classification

The “T - flange normal” ring is available as the

symmetrical form.

The “T - flange antiwedge” ring has an a-symmetrical form. This modification was made toallow more clearance for the yarn between theupper surface of the ring and the traveller.

The form of the antiwedge ring reduces the ring /traveller area of contact and can consequently limitthe maximum traveller speed.

The “S – flange” (inclined) ring which has beendeveloped to increase the contact area between

the ring and traveller and to reduce the pressure.For some yarns higher spinning speeds areattainable with the S – flange ring.

The T – flange rings are designated by the overall width of the flange. Flange 1 – 3.2 mm Flange 2 – 4.0 mm The exception is the Titan AW98 ring that is only 3.2 mm wide.

The S – flange rings are 2.8 mm wide and have the following potential advantages: better heat transfer from the traveller due to the increased contact surface area, which is 4 to 5 times greater

than the T–Flange ring. Simplified running–in period due to lower traveller pressure against the ring surface. Spindle speed can be increased significantly if the yarn can withstand the forces. (Warp yarn up to 25 %

spindle speed increase) Reduced thermal damage to sensitive synthetic fibres. Improved running stability. Fewer traveller changes.

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3.6.1.1. Ring Diameters

The diameter of the ring has to be selected depending upon the requirements of the yarn count and the amountof yarn that can be wound on the bobbin.

Rieter offers a range of ring sizes from 36 mm to 51 mm. The following lists the type of rings available and someof their characteristics;

Ring Applications:

Ring type Flangetype

Flangewidth (mm)

Ring dia.(mm)

Gauge Approx, yarncount (Ne)

Reference

4.0

4.03.2 / 4.0

51

4845

75 5.5 – 20

7 – 24 (30)14 – 36 (40)

LC T-flange

normal

3.23.23.23.2

42403836

70 18 – 6030 – 10040 – 14050 – 160

Ring running in program

necessary

4.04.03.2 / 4.0

514845

75 12 – 2012 – 24 (30)12 – 36 (40)

CR T-flangeanti-wedge

3.23.2

3.23.2

4240

3836

70 18 – 6030 – 100

40 – 14050 – 160

Ring running-in programnecessary, not for coarseryarns

4.04.03.2 / 4.0

514845

75 5.5 – 207 – 24 (30)

12 – 36 (40)

Titan-N 98 T-flangenormal

3.23.23.23.2

42403836

70 18 – 6030 – 10040 – 14050 - 160

No ring running in program

3.2 45 75 14 – 36 (40)Titan-AW98

T-flangeanti-wedge

3.23.2

3.23.2

4240

3836

70 18 – 6030 – 100

40 – 10050 - 100

No ring running in program,medium to fine yarns

ZENIT,TITAN S-flange,ORBIT

S-flange 2.82.82.82.8

42403836

70 18 – 5030 – 7036 – 8045 – 80

High performance (warpyarn)

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The following are some of the points that have to be considered when selecting the appropriate ring diameter.NOTE:

When spinning coarse yarns or yarns with low twist, the production is not limited by the spindle / traveller speedbut by the delivery roller speed of 28.5 m/min.

Within the constraints of traveller speed, the ring diameter can be selected and the considerations are; The maximum traveller speed in m/min is established by the fibres and yarn being processed. The spindle speed is dependent upon the ring diameter. The smaller the ring diameter, the higher can be the spindle speed to reach the maximum traveller speed. The smaller the ring diameter the smaller the weight of yarn that can be wound onto the bobbin. Small bobbins have to be doffed more frequently at the spinning machine. Small bobbins with less yarn per bobbin require more handling and splicings per kg of yarn at the winder. For optimal spinning, the length of the bobbin (tube) should be 4.7 to 5 times greater than the ring diameter.

Consequently as the ring diameter is reduced so is the tube length that further lowers the amount of yarn

that wound on to the bobbin. Small rings are for fine yarns and large rings are for coarse yarns.

3.6.2. Traveller speeds

The maximum traveller speed has been increased over the years as technology and materials have beendeveloped. The maximum traveller speed has to be determined by a series of tests to consider the yarn qualityand spinning performance. This criterion is usually established before machines are specified.

As a guideline:

When spinning cotton at 35 m/s, the traveller is considered to be running at a very high speed. Manufactures of Man made fibres usually suggest that the traveller speed be limited to 28 to 30 m/s. Those fibres that have a low melting point, such as polypropylene, require traveller speeds well below 28

m/s. It is necessary to obtain the recommendations of fibre supplier.

The following chart shows how the spindle speed varies in relation to the ring diameter to result in a travellerspeed of 28 m/s. and 35 m/s

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Influence of Ring Diameter on Spindle Speed and Traveller Speed



Technology Handbook

3.6.2.1. Traveller form

C – shaped traveller As a basis for considering traveller form, the C-shapedtraveller is shown as an illustration.

1 Inner traveller width2 Height of bow3 Yarn passage4 Wire section5 Traveller - ring contact surface6 Angle of toe7 Toe8 Opening9 Upper part of traveller bow

The cross-sectional form and the shape of the travellers have been developed for specific applications and haveto be selected for each type of yarn being spun. Examples of the Braecker traveller types are shown below.

Illustration of Wire Selections

fGood results regarding hairiness. Suitable for fine cottonyarn and viscose.

drFor blends, cotton and synthetics. Good results for lowtwisted yarns.

udrFor cotton, blends and synthetics. Extremely wide half-round profile offers a large contact surface. For high

speeds.

frFor acrylics, special synthetics and core yarn. Flat toe,round traveller bow (yarn passage), for higher speeds.

rFor synthetics and core yarn, for lower speeds.

drhFor SU travellers. Also available with udr and r profile.

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3.6.2.2. Traveller applications

The selection of travellers for a specific yarn is somewhat complicated. The decision is based upon:

Type of flange: T-flange or Orbit. Material: such as cotton or yarns containing man made fibres. Yarn count: coarser or finer than Ne 40/1. Ring flange size: No 1 or No 2 flange (3.2 mm or 4.0 mm) Ring profile: normal or antiwedge.

To assist in the selection process, the following Braecker charts are included.

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Technology Handbook

It is strongly recommended that each erector working on the ring-spinning machine obtain a copy of the Braeckerbooklet. For your convenience, the Bräcker Manual English 2003.pdf has been added to this CD-ROM.

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3.6.2.3. Traveller weight

The weight of the traveller should be as light as possible, but the balloon must remain stable. The balloon mustbe considered at all phases of the bobbin, from the first windings at the bottom to the last windings duringpreparation for doffing.

The following chart is calculated with the GRISHIN formula and is a guide to the range of traveller weights fordifferent yarn counts.

The balloon must not collapse during the doffing or start-up phases of spinning. It is important to consider theballoon form above the balloon control ring when selecting the traveller weight.

Traveller Weights for Cotton and Blend Yarns

3.6.2.4. Estimation of wear and tear of the ring and traveller

The wear and tear of the traveller has to be monitored to see if the traveller is tracking correctly, otherwise

damage of the ring could result.

Visual inspection:

the travellers have to be removed with tweezers to prevent breakage. A visual inspection is necessary to seethe wear distribution and where the traveller is making contact with the ring.

A sample of at least 100 travellers should be inspected to form a reliable judgment. If the number of travellers judged to be badly worn exceeds 15% of the total inspected, all the travellers

should be changed.

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The following illustration shows the wear characteristics of travellers, how to interpret the appearance and whatcorrective action should be taken.

Evaluation of Traveller Wear – for the T-flange Ring

The wear and tear of the ring traveller is a good indicator for the state

Average weight loss Maximum weight loss.End of traveller life

Excessive wear. - Danger!

Ring damage from excessivetraveller wear.of the spinning rings.

Periodic checks of the ring traveller, generally prevent a prematurebreakdown of the spinning rings.The amount of wear and tear on the ring traveller is also an indicationof whether the weight of the ring traveller and the spindle speed are correct.

The maximum life-time of the travellers can also be determined by the wear.

On no account may the limits indicated in the «Criteria of evaluation» be exceeded.Should the limits be exceeded:

– reduce the speed of the spindles by 5%, or – shorten the running time of the travellers by 20%

Otherwise the service life of spinning rings will be shortened. Possible ways to estimate the wear: – Visual (abrasion marks) – Loss of weight (gravimetric) – Amount of ring travellers breakdowns

There are two abrasion marks on the ring traveller. Mark 1, is on the inside prong of the ring traveller,mark 2, is in the head radius area of the ring traveller. The ratio between the two marks is an indicator for theweight.

Evaluation of Traveller Wear – for the ORBIT Ring

– Both marks show approximately equal abrasion►the weight of the ring traveller is correct.

– No or very light abrasion in the head radius, heavyabrasion in the inside prong area►the ring traveller is too light.

– Heavy and relatively deep abrasion in the head radius

area, normal or lighter abrasion in the inside prong area►the ring traveller is too heavy.

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Average wear pattern.End of traveller life.



Technology Handbook

3.7. Balloon control ring

With relatively long bobbins and narrow gauge machines it is frequently necessary to use balloon control rings tolimit the size of the balloon. Without the balloon control ring it would be necessary to use very heavy travellers tocontain the balloon size, but this leads to high yarn tension and yarn breaks.

The balloon control ring divides the balloon into two smaller balloons and facilitates spinning with relatively lowtensions.

Balloon Control Ring The yarn rubs against the surface of the ballooncontrol ring at speeds similar to the traveller speed.(30 m/s = 108 km/hr)

The balloon control ring must not interfere with the

movement of the yarn

They should be clean and not contaminated with fibrefinish.

They should not be damaged or scratched.

Balloon control rings can cause roughening of theyarn, fusing of heat sensitive fibres and fibreshedding.

3.8. Bobbin build

The vast majority of bobbins are wound with the “filling” (cop) build. The bobbin is formed in three parts: the curved base, the cylindrical body and the conical top.

The winding procedure is:

The ring rail is raised slowly to “wind” the yarn and is then moved downward at a higher speed to lay coils atan increased helix angle to lock-in the previous layer.

The upward and downward movement is referred to as the stroke. The height of the stroke is normally about 15 to 20% greater than the diameter of the ring. The downward movement of the ring rail is 2 to 3 times faster than the upward movement. The combination of the two layers having different winding angles is beneficial in the stability of the build in

the re-winding process. Occasionally the spinning ends down will be higher during the faster downward movement and should be

considered in setting up the speeds and conditions of the machine. The stroke is short at the beginning of the build and is increased throughout the formation of the curved

base. After the base formation the stroke length remains constant.

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The spinning tension is greatest when the yarn is being wound directly onto the tube at the bottom of the buildand the spindle speed has to set accordingly. Maximizing the production can be accomplished using the speed

curve program:

During the first part of the build the spinning speed has to be established to minimize spinning breaks. As the package builds and the balloon length is shortened, the spinning tension is reduced. To maximize production, a control program is used to increase the spindle speed throughout the build to

take advantage of the reduction of balloon forces. The control program also slows down the spindle speed prior to stopping for the doffing cycle.

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4. RECOMMENDATIONS

4.1. Start-up suggestions

Prior to spinning it is very important that the machine be in a correct operating condition. Check that the machine is correctly levelled. Inaccurate levelling can produce an “out of round running

condition that frequently shows up as a 10 cm spectrogram peak in the yarn. The rings must be correctly centred, (Very Important) preferably using the electronic indicator. The device

should be carefully calibrated. The centring function should be performed by the erector and not left toassisting personnel provided by the plant.

Check to be sure that the yarn thread guides are correctly located over the tubes. The yarn balloon must besymmetrical around the bobbin.

Ensure that the ring rail is level over the full length of the machine, otherwise the doffing function will becompromised and the bobbin build will not be uniform.

Check the setting of the roving guides to be sure that the roving will pass through the drafting system in thecentral zone.

Set the draft roll distances for the fibres to be spun. In most case the rolls will have been pre – set accordingthe customer’s fibre specifications.

Set the break draft and total draft according to the roving size and the required yarn count. On the basis of the fibres to be spun and the yarn count needed, select one of the standard settings for:

Cradles and aprons,Roller settings – bottom and top,

Draft distribution.

Set the spindle speed, taking note of any pre-sales tests that have been done. Program the speed curve, the bobbin build and the bobbin weight so that critical conditions are avoided at

start up Select the traveller type as established by any pre sales trials or use those supplied with the machine. If necessary set the traveller clearer for the type and size of the traveller to be used. If possible avoid

changing the clearer positions until the running conditions are established. Follow the Ring Run-in program when setting up a new machine. Pre spin on 10 to 20 positions for sizing and initial checks of balloon form and the general spinning

conditions. Feed the roving immediately ahead of the spinning-on step. Avoid having multiple ends of roving being

drafted and feeding fibre to the waste collection system while other ends are being started. At the start of spinning, clamp the seed yarn under the tube and wind approximately five wraps around the

bobbin at a height not to exceed the strokes of the ring rail. Avoid winding “start up yarn” above the corresponding ring rail stroke. Excessive start up yarn on the bobbin

tends to become entangled in the yarn as it is being wound. It also creates problems of yarn dragging at thewinding machine.

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4.2. Illustrations of Starter Windings

Windings for “Start Spinning”

Bad starter winding, NOT coveredby the first layers of yarn.

Bad starter winding.

Good starter winding, covered bythe first layers of yarn

Good starter winding.

Adjust the traveller weight so that a correct balloon form is created. The traveller must not be too lightwhereby the balloon will collapse, nor too heavy causing the balloon the contact the top of the tube over theyarn tension.

4.3. Recommendations for downstream processing

COM4® as every yarn type, owns an own characteristic. This also means that there are sl ight differences indownstream processing. In the following chapter you will find some of these differences explained and how to re-act.Generally spoken, COM4® is a compacted yarn. Fibers are more straightened and more paralyzed. This meansthat the diameter of the yarn body is about 2 % less (UT 4) than conventional ring yarn. Additionally the hairinessis strongly reduced. Tenacity and elongation are increased.This means gives you the following points of attention:

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4.3.1. Knitting

Covering is worse- ask for yarn with lower twist- decrease loop length- find different constructions using visibility of knitting construction

Exchange of existing articles- when copying existing articles, the result with COM4® yarn may differ- reasons are missing hairiness and lower covering (see above)- create new articles for compact yarn to show the yarn characteristics to its best advantage

Yarn tension- caused by the reduced hairiness, yarn tension may differ during processing

- check and correct the adjustment of brakes

Fiber fly is less- increase interval of cleaning cycles- look more for constructions using different fiber types or different colors(you will have much less troubles than with conventional ring yarn)

Lower hairiness for better optic- use the potential regarding luster und brilliancy- find high-value articles- consider eliminating the singeing process

Eliminate singeing- due to the better structure of the yarn, singeing can be eliminated in many cases- lower wear and tear on the knitting machine- increase interval of cleaning cycles

Higher security regarding ends-down- higher, uniform strength gives the opportunity to increase number of machines per worker- think of non supervised shifts

Color- COM4® colors look more cold than hairy conventional ring yarn

- the same amount of dye stuff gives darker shades

Needle wear and tear- about 25 to 30 % less needle wear and tear gives the opportunity to keep needle longer time- more preferable is to change needles after the same time as for conventional ring yarn, but reduce secondquality (gives more profit)

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4.3.2. Weaving

Covering is worse- find the right construction- use 2 threads drawing-in in the reed- ask for yarn with lower twist- increase number of threads per unit

Exchange of existing articles- when copying existing articles, the result with COM4 yarn may differ- reasons are missing hairiness and lower covering (see above)- create new articles for compact yarn to show the yarn characteristics to its best advantage

Lower hairiness for better performance

- lower hairiness needs lower amount of sizing agent- shed opening can be reduced for higher speeds and more warp shafts- reduced clinging for less tension peaks and higher efficiency

Lower hairiness for better optic- use the potential regarding luster und brilliancy- find high-value articles- consider of eliminating the singeing process

Fiber fly is less- increase interval of cleaning cycles- look more for constructions using different fiber types or different colors(you will have much less troubles than with conventional ring yarn)

Higher security regarding ends-down- higher, uniform strength gives the opportunity to increase number of machines per worker

- higher, uniform strength gives the opportunity to increase loom speed- less second quality- higher efficiency

Eliminate mercerizing- due to the higher brilliancy mercerizing may be eliminated

Color- COM4® colors look more cold than hairy conventional ring yarn- the same amount of dye stuff gives darker shades

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4.4. Center-P+ Electronic centring device for spindles

4.4.1. General

The Center-P+ centre pointer is used to centre spinning rings on Ring spinning machines. Correct centring of ringto spindle has a crucial influence on the yarn quality and on the number of yarn breaks.Centring with the bare eye depends mostly on the person doing the job and on the condition of the spindles. It isdifficult to centre all spindles uniformly with this methode, since machines may have more than 1000 spindles.Furthermore, a visual centring is not always possible on Ring spinning machines of modern design.

The Center-P+ spindle centre pointer does the job with the help of a light-emitting diode (LED) display, whichshows reproducible results and can be interpret objectively. With the centre pointer, the job can be done easilyand without tiring, even on long machines.

This handy device is battery-powered and can be used during a whole shift without line connection.

The centre pointer can be used on spindles with a diameter between 16 mm and 18 mm, adapters are availablefor spinning ring diameters 36 mm to 48 mm.Its open design allows the Center-P+ centre pointer to be attached to the ring at any point, over the runningspindle from the side. The balloon control ring, or thread guide is no obstruction. The ring traveller does not haveto be removed; it only needs to be pushed backward into the open section of the centre pointer.

The Center-P+ centre pointer can also measure on top of the conical part of a spindle, eliminating the need tostop the spindle and put on a cylindrical casing, just to removed it again after the centring process. A spring-loaded gripping device holds the centre pointer onto the spinning ring and compensates for themanufacturing tolerances of the ring.

The display consists of two lines of LEDs perpendicular to each other. Red diodes show in which direction the

ring should be moved, and a green diode lights up when the spindle is within a radius of +/- 0,15 mm from thetheoretical centre point of the ring.

4.4.2. Directions for UseThe battery supplied with the centre pointer should be charged before the device is used the first time.

Switching onBefore the device is switched on, ensure that it is equipped with the correct ring adapter, if necessary exchangethe adapter.

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To switch the Center-P + centre pointer on, connect the hand-held part of the device to the battery via the spiralcable. With the device switched on and sufficient battery charge, the outermost red LEDs light up alternately, to

show that the device is ready for use. A blinking green LED means the battery is low and the centre pointer cannot be used.

If the battery remains connected in this condition, the electronics will automatically switch off the device.It is strongly recommended that the device be always disconnected from the power source after use. This mustalso be done if the battery is discharged. A discharged battery should be charged as soon as possible, to ensurethat the device is always ready for use.

Placing the centre pointer Activate the lever, to retract the clamping pins into the housing and place the measuring head sideways over thespindle onto the spinning ring.

Ensure that no traveller is within the area of the support surface of the centre pointer, to be trapped under theadapter. When the lever is released, a spring presses the clamping pins evenly outwards and holds the centrepointer centrically on the ring to be adjusted.With a slight twisting motion, the optimal seating of the centre pointer on the ring can be ensured.Eight red and one green LEDs indicate the position of the ring relative to the spindle when the device is mountedon the ring.

The active red LEDs show the direction in which the ring with the device has to be adjusted. If the red LEDs are litonly in one direction, then the ring must be adjusted in the direction shown until only the green LED is lit.

It is important to note, that the display of the red LEDs is not linear—see the following diagram.

Green LED: Spindle is centred; spindle position is within +/- 0,15mm of the theoretical centre point.

Centring precision is good.

"Red-1" LED: Spindle is not centred; it is inside a circle with aradius of max. +/- 0,25 mm from the theoretical centre point.

Centring precision is fair.

"Red-1" and "Red-2" LEDs: Spindle is within a circle with a radius

of max. +/- 0,4 mm from the theoretical centre point.

"Red-2" LED: Spindle is outside the circle with a radius of > 0,4 mm from the theoretical centre point.

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Example:

Example 1) Example 2) Example 3)X < 0,15 mm 0,15 mm < X < 0,25 mm 0,15 mm < X < 0,25 mm Y < 0,15 mm 0,15 mm < Y < 0,25 mm 0,25 mm < Y < 0,40 mm

Example 4) Example 5) Example 6)0,25 mm < X < 0,40 mm X > 0,40 mm X < 0,15 mm0,25 mm < Y < 0,40 mm 0,25 mm < Y < 0,40 mm Y > 0,40 mm

With the centre pointer in place, the ring should be carefully adjusted until the device is positioned so that only thegreen LED is lit.When this position has been reached, the fastening screws on the ring can be tightened. Make sure, the ring isnot shifted out of its correct position while this is done.

4.4.3. Exchanging the centring adapter

The Center-P+ centre pointer can be equipped with adapters for ring diameters between 36 mm and 48 mm.To exchange the adapter, two screws must be loosened with a 2,5 mm spanner. Gently remove the metallic partfrom the plastic part.When mounting an adapter, ensure that the two plastic projections on the centre pointer housing engage in theappropriate positioning holes on the adapter, and that the adapter is firmly seated around its entire circumference.The two fastening screws can then be tightened with moderate force.The adapter is a precision instrument and must be handled with care. Store the adapters in the appropriatepocket of the carrying case, when not in use.

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4.4.4. Maintenance

The apparatus requires no regular maintenance. If necessary, wipe off any soiling with water and a little soap.Use no solvents, as they might destroy the plastic materials in the device. As needed, the moving parts of the ring adapter can be lightly oiled with fine sewing machine oil.

4.4.5. Charging the battery

The charger is microcomputer-controlled. As soon as the green LED on the device lights up, the charging processis complete and the Center-P+ is ready for use.With a fully charged battery the device can be used for more than 10 hours without interruption, although theduration of one charge depends on how the centre pointer is used and on ambient conditions.

The green LED will blink when the accumulator is getting empty.

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4.5. How precise must the „ring centring“ be?

Centring of spinning rings remains a central topic in relation to yarn quality. Mostly for reasons of time,inadequate care is devoted to the ring centring process.How „precise“ the spinning rings were centred, is particularly visible in the yarn hairiness.The visual hairiness testing with the Zweigle methode – as expressed in the value S3 - reacts very sensitive inthis matter.With the Uster UT4, the hairiness testing captures the deviations of inaccurately centred spinning rings as well.However in terms of absolute-numbers, the variations are smaller and thus the user is sensitized to a lowerdegree toward of accuracy of spinning ring centring.Nevertheless a good correlation to the value S3 exists with the H Sh 1m values of the UT4.

4.5.1. Centring methods

Ring centring can be accomplished with different methods however with unequal success concerning accuracy.the visual light gap method

centring with the “RES” device (E.Schweizer)centring with the Center P+ (Freespring)

4.5.1.1. Goal

The goal consists of centring all spinning rings as accurate as the yarn quality requires under consideration of therespective conditions.

4.5.2. Results from experience

The quality criterion of yarn hairiness is just as important as the evenness or the IPI values. As mentioned before, inaccurately centred rings are explicitly apparent in the yarn hairiness value. Within theother lab-test parameters, no striking deviations develop that would be eye popping.

The optical testing methode with Zweigle reacts particularly sensitive to inaccuracies of ring centring. The Zweigledevice measures those fibres, which are raised from the yarn body and expresses the frequency, arrangedaccording to fibre length. The commonly used indication „S3“ represents the number of hairs per 1m yarn, thatare equal to and longer than 3 mm.The hairiness test with the Uster UT4 method, does not measure /arrange according to lengths. As disadvantagecan be said, that the H value reacts substantially less sensitive, in contrast however, a Spectrogram with possibleperiodicities is depicted and the H Sh 1m value exhibits a good correlation with the S3 value.The rise in S3 is not only produced by an inaccurately centred spinning ring, but also the change in thread tensionon the Ring spinning frame can be a significant perpetrator. Therefore, both testing methods must be used tolocate the problem.

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4.5.2.1. Yarn hairiness depending on the centring accuracy

Bobbins were taken randomly from 10 spinning positions each, of normal and diagonal flange rings. Theinaccurately centred rings resulted in a significantly higher, thus worse hairiness value – Zweigle test – whencompared against the accurately centred rings.When testing the hairiness of the same yarns with the Uster UT4-H, differences in favour of the accuratelycentred rings are visible, however not as obvious as with the Zweigle methode.

Hairiness Zweigle and UT4-H depending on centring accuracy Average value from 10 spinn ing positions

0

1

2

3

4

5

6

7

8

9

10

11

12

13

H a i r i n e s s :

S 3 v a l u e ,

U T 4 - H v a l u e [ H / m , ]

inaccurately centred accurately centred

Normal flange (Titan N98) Diagonal flange (Titan Orbit)

Z w e i g l e S 3 v a l u e

U T 4 - H v a l u e

Hairiness Zweigle and UT4-H depending on centring accuracy Average value from 10 spinn ing positions

0

1

2

3

4

5

6

7

8

9

10

11

12

13

H a i r i n e s s :

S 3 v a l u e ,

U T 4 - H v a l u e [ H / m , ]

inaccurately centred accurately centred

Normal flange (Titan N98) Diagonal flange (Titan Orbit)

Z w e i g l e S 3 v a l u e

U T 4 - H v a l u e

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4.5.2.2. Yarn hairiness of the extreme spinning positions

During the closer investigation, the large spread within the 10 spinning positions was noticed. Thus the highaverage value was caused by only a few spinning positions, which exhibited insufficient centring.The deviations were > 0.40 mm. This is demonstrated in the following diagram.The inaccurately centred spinning ring, creates an obviously higher occurrence in all length classes of hairiness.However, if the centring accuracy is kept by < 0.25 mm over all spinning positions, resulting in a smaller spread, alower average in the hairiness value S3 is realized.

Centring accuracy from two extreme spinning positions

0

5

10

1520

25

30

35

40

4550

55

60

65

70

7580

85

90

95

100

1 2 3 4 6 8 S3

Length of extruding hairs [mm ]

Z w e i g l e - H a i r i n e s s [ H / m

]

Spin.pos. 2, accurately centred

Spin.pos. 7, inaccurately centred

Centring accuracy from two extreme spinning positions

0

5

10

1520

25

30

35

40

4550

55

60

65

70

7580

85

90

95

100

1 2 3 4 6 8 S3

Length of extruding hairs [mm ]

Z w e i g l e - H a i r i n e s s [ H / m

]

Spin.pos. 2, accurately centred

Spin.pos. 7, inaccurately centred

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4.5.2.3. Yarn hairiness within 10 Spinning positions

The test-yarns were taken from the identical 10 spinning positions. On one hand with accurately centred spinningrings and on the other hand with inaccurately centred positions (normal flange).

Yarn hairiness depending on ring centring (Yarn Ne 30)

2

3

4

5

6

7

89

10

11

12

13

14

15

16

17

18

1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10

Spinning position number (Normal flange)

H a i r i n e s s : Z w e i g

l e S 3 / U s t e r U T 4 - H [ H / m ] accurately centred

inaccurately centred

Uster UT4-HZweigle S3

Yarn hairiness depending on ring centring (Yarn Ne 30)

2

3

4

5

6

7

89

10

11

12

13

14

15

16

17

18

1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10

Spinning position number (Normal flange)

H a i r i n e s s : Z w e i g

l e S 3 / U s t e r U T 4 - H [ H / m ] accurately centred

inaccurately centred

Uster UT4-HZweigle S3

4.5.2.4. Yarn quality depending on the accuracy of centring

We examine now, how the Uster evenness and the imperfections are influenced by the centring accuracy of thespinning rings, as shown in the following diagram.

Yarn quality depending on centring accuracy (10 Sp.pos. each)

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

UT4

CVm%

Thin-

place -40%

Thick-

place +35%

Neps

140/200%

U s

t e r v a

l u e

C V m ,

I P I [ % , A m o u n t . / 1 0 0 0 m

]

N98 inaccurate N98 accurate

curate ccurate

Yarn quality depending on centring accuracy (10 Sp.pos. each)

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

UT4

CVm%

Thin-

place -40%

Thick-

place +35%

Neps

140/200%

U s

t e r v a

l u e

C V m ,

I P I [ % , A m o u n t . / 1 0 0 0 m

]

N98 inaccurate N98 accurate

curate ccurate

Orbit inac Orbit aOrbit inac Orbit a

The average values of the individual columns are derived from 10 bobbins each. The yarns were spun withnormal- and diagonal flange rings, always on the same spinning positions.

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Deterioration in yarn quality values, caused by inaccurately centred spinning rings, are not as obvious as inhairiness. The evenness and the thin places change only marginally. However, difference in thick places are

slight noticeable and a significant increases in the nep value is obvious, always in favour of the accurately centredspinning rings.

4.5.2.5. Yarn hairiness depending on the yarn tension

The increase in hairiness does not always have to be caused by the inaccuracy of spinning ring centring. Theyarn tension on the Ring spinning machine, for example, is the most important influencing factor in changes of theyarn hairiness.The following diagram shows the relationship between yarn tension and yarn hairiness (Zweigle methode).The spindle speed and the Traveller weights were varied within the same spinning positions, with accurately

centred spinning rings (normal flange).This results in different yarn tension values, which then leads to variable hairiness.The spindle speed affects the yarn tension only moderately and therefore, influences also the yarn hairiness onlymodestly.However, varying the Traveller weight entails clear changes in yarn tension. Accordingly, these changes cause adifferent integration of the fibres in the spinning triangle, which leads to altered values in the yarn hairiness.

The smallest yarn tension, lowest spindle speed and lightest Traveller, produces an unfavourable integration ofthe fibres and the highest yarn hairiness. In opposite, the highest yarn tension with maximum spindle speed andheaviest Traveller, achieve the best yarn hairiness values.

Yarn hairiness depending on yarn tension (Yarn Ne 30)

5

6

7

89

10

11

12

13

14

15

16

17

18

19

20

21

ISO 40 45 50 ISO 40 45 50 ISO 40 45 50

The variables: Traveller weight and spindle speed

H

a i r i n e s s : Z w e i g l e

S 3 [ H / m

]

20

21

22

23

24

25

26

27

28

Y a r n t e n s i o n

[ g ]

Zweigle S3 value

Yarn tension

17'600 rpm17'000 rpm16'500 rpm

Yarn hairiness depending on yarn tension (Yarn Ne 30)

5

6

7

89

10

11

12

13

14

15

16

17

18

19

20

21

ISO 40 45 50 ISO 40 45 50 ISO 40 45 50

The variables: Traveller weight and spindle speed

H

a i r i n e s s : Z w e i g l e

S 3 [ H / m

]

20

21

22

23

24

25

26

27

28

Y a r n t e n s i o n

[ g ]

Zweigle S3 value

Yarn tension

17'600 rpm17'000 rpm16'500 rpm

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4.5.3. Centring device „RES“

With the introduction of the G33 Ring spinning model, which has fix-mounted balloon control rings andseparators, the measuring head needed to be redesigned, from an enclosed to an „open“ execution. When Rietermandated again to centre the spinning rings with the RES device, a renewed design effort took place. At the beginning of 2000 a practical measuring head was available for the G33 and K44 and made the RES theonly useful centering device available on the market.

Some thoughts in regard to the RES device:+ Very precise measurements are possible.+ The gradations of the LEDs are very fine.+ The measuring head can be adjusted very precisely and relative easy.+ The claw wedging of the open head design, centres the ring easy, precisely and firmly.+ An pair of half-sections made out of special plastic is available for each ring diameter, for the measuring head.

- Centring is only possible with an auxiliary steel tube over the spindle.- The time requirement is substantially higher when compared to the visual light-gap method.- The measuring head can be damaged very easily during the centring procedure.- The device is relatively expensive and therefore not utilized as much.

4.5.4. Centring device „CenterP+“

Because of the difficult ring centring with the RES and the inaccuracy with the visual light-gap method, a simplernevertheless exact centring device had to be found.

The company Freespring already had an uncomplicated centring device on the market, but the measuring headdesign on this device was also enclosed and therefore, could not be used on the G33 and K44.Rieter was interested in this device and a cooperation to develop a new „open“ measuring head matured.

4.5.4.1. Requirement specifications from 2000

The requirement specificans read:

• Open measuring head, access through the spindle (not over the spindle).

• The sensor must read directly from the spindle, without auxiliary tube.

• The Traveller-cleaner and the applied Traveller must not disturbe the measuring head, which must have

an accommodating recess area.• The device must be operated with an accumulator, no power cable.

• The centring accuracy of max. +/- 0.14 mm (the green range) must be assured, because this eccentricdeviation can be rated as good.

• The centring device should be easy to handle and intuitive.

• Sufficient space must be at hand for the centring procedure.

• A zero-gauge must be available to check and calibrate the measuring head.

• The required time for the technician may not be higher than with the visual method (approx. 40-60 sec.).

• The spindle speed and ring rail height are flexibly.

• The same adapter must be suitable for the normal- as well as diagonal flange ring

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Here are the two ring profiles depicted, which can be serviced with the measuring head.

Normal flange Diagonal flangeTitan N98 Titan Orbit

4.5.4.2. Practical application

At the end of March 2004 the newly conceived centring device „CenterP+ “, with the open measuring head wasdemonstrated in the SpinCentre of Rieter. During this occation the device was tested on different Ring spinningmachines such as G33 and K44, whereby some issues concerning shape and handling arose.

The most important shortcomings were:

• Device touches the separators (form),

• redesign of the releasing lever (because of thread monitoring), and

•

refinement of gradations of the eccentricity.

The CenterP+ device fulfilled nearly all given conditions, only the control gauge was still missing. Even theexisting „tapping tool“ can be used together with the new centring device.

At the beginning of 2005 the centring device „CenterP+“ had reached its current condition.

The centring device is offered in two colours; Blue colour: CenterP+ with closed measuring head (Freespring) Red colour: CenterP+ with open measuring head (Rieter)Based on today's sales figures it can be said that the CenterP+ device had a very successful start.

4.5.4.3. Complaints

Case 1The task was to centre on the Ring spinning K44. With the CenterP+ the spinning rings had been centred into thegreen range (illumination green /red flickering).With full bobbins a clear “out of centre” deviation was shown on all spinning positions, in the same direction. A double check with the RES resulted in an eccentric deviation of up to 0.50 mm.Doubts arose and we requested an inspection gauge, which proved a deviation in our CenterP+ device.

As a consequence, we requested an inspection gauge for all ring diameters.

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Case 2In May 2006, a message came to Rieter, that in 2 to 3 cases a severe centring error had developed on customer

site using the new centring device on G33 Ring spinning machines.First, the original inspection gauges were missing at the customer site. Research for the reason of this problemreveiled, that this device was outside of the manufacturing tolerance.

4.5.4.4. Comparison measurements

Basic data:To develop some reference points with the CenterP+ versa the “RES” device, various test measurements werecompleted in the SpinCentre by Rieter.

The data: Spinning ring Titan N98 40 mmSpindle rpm 10'500 min-1Ring rail in middle positon of total stroke

Devices : CenterP+ versa RES device - calibrated to +/- 0 to 0,02 mm

> 0,40

X- Axis

Y - Axis

< 0,15

< 0,25

< 0,40

> 0,40

X- Axis

Y - Axis

< 0,15

< 0,25

< 0,40

The measurement concept

The zero point, green LED, can exhibit an internal tolerance of +/- 0.12 mm.

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4.5.4.5. The gradations

The gradation of the eccentricity is depicted in the following diagram.

2. red

1. + 2. red

1. red

green

Zero point

tolerance

Eccentrically [ +/- mm ]

Present

Goal

0,250,150,12 0,400,70 >0,40

2. red

1. + 2. red

1. red

green

Zero point

tolerance

Eccentrically [ +/- mm ]

Present

Goal

0,250,150,12 0,400,70 >0,40

The allowed deviation of the zero point is with +/- 0.12 mm too high. This covers almost the tolerated green rangeand thus can lead to an eccentricity that reaches outside of the green range.

The tolerance for the zero point clearly must be reduced.

4.5.4.6. The comparative measurements

From a set of comparative measurements between CenterP+ and the “RES” device, the most interesting settingsare depicted below (test 1. / 3. / 5. / 6. / 8.).

y +

1. Centred with RES device

x-0,04 y+0,02

checked with Center P+

green / red y- flickering

x - x +

Center P+

LED flickering

RES-Device

y -

y +

1. Centred with RES device

x-0,04 y+0,02

checked with Center P+

green / red y- flickering

x - x +

Center P+

LED flickering

RES-Device

y -

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y +

5. Centred with Center P+

green / red1 (x+ und y-) flickering

checked with RES

x +0,02 y +0,02

x - x +

Center P+

LED flickert

RES-Device

y -

y +


green indication (middle)

checked with RES

x -0,07 y +0,04

x - x +

Center P+

LED flickering

RES-Device

y -

y +


green / red1 (x+ und y-) flickering

checked with RES

x +0,02 y +0,02

x - x +

Center P+

LED flickert

RES-Device

y -

y +


green indication (middle)

checked with RES

x -0,07 y +0,04

x - x +

Center P+

LED flickering

RES-Device

y -

y +


red2 x+ and red2 y-

checked with RES

x +0,5 y -0,35

x - x +

Center P+

LED flickered

RES-Device

y -

y +


red1 x+ and red2 x+ / red1 flickered y-

checked with RES

x +0,16 y +0,15

x - x +

Center P+

LED flickered

RES-Device

y -

y +


red2 x+ and red2 y-

checked with RES

x +0,5 y -0,35

x - x +

Center P+

LED flickered

RES-Device

y -

y +


red1 x+ and red2 x+ / red1 flickered y-

checked with RES

x +0,16 y +0,15

x - x +

Center P+

LED flickered

RES-Device

y -

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4.5.4.7. Position of CenterP+

When evaluating the position of all test measurements versa the RES device, a predominant correction for bothaxles and in the same direction is necessary. The following table demonstrates the measured positions during thedifferent tests, versa the RES device. The CenterP+ device in the SpinCentre exhibits a systematic eccentricerror of 0.10… 0.20 mm.

Necessary positional correction with Center P+

Test

in x-axis in y-axis

Positionto RES

Working rangeCenterP+

1. ▲0.10 green

2. OK green

3. OK green

4. OK green

5. ◄0.10 ▲0.10 green / (red)

6. OK red 2

7. ◄0.10 ▲0.15 red 2

8. ◄0.15 ▲0.20 red 1 and 2

9. OK red 1 and 2

10. ▼0.10 red 1

11. ◄0.15 ▲0.10 red 1 (2)

4.5.5. How precise must the ring centring realy be?

The light gap methodThis is not a reliable system for centring the spinning rings. It is a visual method, which depends very intensely onthe condition of the person, it is fatiguing for the eyes and the light conditions are rarely optimal all the way

around the ring circumference. This method regularly results in “out of limit” rings.

Electronic centringThe diagrams from the field trials emphasize, that whether normal- or diagonal flange spinning rings, the centringmust be performed with an electronic device.

Today the available device choice remains between:

• CenterP+ this unit is handy, simple, without power cable, relatively inexpensive.

• RES device very exact, but more elaborate.

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4.5.5.1. Accuracy of centring

Although the ring centring is an unpopular and complex activity, it remains a central and important task within anRing spinning operation. With today's yarn quality requirements, it is inevitable, that the spinning rings areadjusted to an eccentricity of less than 0.25 mm. This can only be ensured with an electronic device over theentirety of a Ring spinning machine and not with the visual methode.Even if the amount of rings “out of tolerance” amounts to only a few percent, these few Bobbins however, cancause a considerable defect in the end product.To avoid out of tolerance rings when using the electronic centring devices, the centring device must be check andadjust regularly and on location for accuracy.

The appropriate control gauges for the CenterP+.

The degree of centring accuracy is individual and depends on the respective customer. With the electronicdevice, it must be centred „as good as necessary“, however of high importance is the uniformity over allspinning positions.

The accuracy generally depends on the spindle speed and the required yarn quality.

Spindle speeds in the upper segment require a more accurate centring within the range < 0.15 mm.With lower speeds and coarser yarns the spinning rings are to be centred within the range < 0.30 mm.

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4.6.8. Exhaust air / SuctionTo be added later.

4.6.9. Room ConditionsTo be added later.

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5. TROUBLE SHOOTING

5.6. Break Draft Zone

5.6.1. Roll settings too close Over control of the roving, Thick places in the yarn, Un-drafted roving (hard ends) Uneven yarn, High ends down

5.6.2. Roll setting too open Loss of fibre control, Uneven yarn, Lower breaking strength.

5.6.3. Break draft too low Irregular drafting (stick / slip effect). – fibre packages. Increased workload in the main draft zone.

Excessive apron wears.

5.6.4. Break draft too high Insufficient fibre control. Irregular yarn – thick and thin places.

5.7. Main Draft Zone

The primary function of the main draft zone is to control the fibres during drafting. This applies particularly to thecontrol of the short “floating fibres and is accomplished by using the double apron drafting system.

5.7.1. Settings

The length of the fibres being processed establishes the –

Bottom roll setting, Cradle size. Bridge.

The top rolls have to be set according to the spacing of the bottom rolls.

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Vertically above the bottom rolls or 1 – 2 mm behind bottom rolls. The top roll cots have to be selected to suit the fibres to be spun and the required yarn characteristics.

The cots have to be well maintained to retain the necessary yarn quality and spinning ends down level.

The spacers have to be established by optimization to meet the yarn requirements and spinningperformance.

Thin spacers increase the fibre control, which –

Reduce yarn elongation and strength, Create broken fibres, Increase the ends down rate, Improve the yarn evenness. Increase drafting forces.

Thick spacers reduce drafting forces and result in:

Higher yarn strength and elongation, Worse yarn evenness CV%.

5.7.2. Synthetic Bottom Aprons

Advantages, Synthetic aprons normally perform well,

Endless with no joint or seam, Serviceable and not expensive, Resistant to fibre finishes. Normally used for man made fibres, blends and medium/ coarse yarns.

Disadvantages, Increased friction over the apron tension bar, Tendency to “ stick / slip”, Can generate vibrations in the draft zone.

5.7.2.3. Leather Bottom Aprons

Advantages, Flexible, Low friction over the tension bar, Smooth drafting action. Normally used for the spinning of fine cotton yarn

Disadvantages, Not endless, - glued at the seam, Fibre finishes tend to cause premature aging of the leather,

Expensive.

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5.7.3. Top Aprons

Top aprons are always synthetic materials.

5.7.4. Positioning of the Bottom and Top Aprons.

The bottom rolls must be positioned so that the bottom roll flutes are aligned with the knurls of the toprolls.

The bottom aprons should run in the centre of the fluted area, The top aprons must run exactly over the bottom aprons. The roving guide should be centred relative to the aprons.

5.7.5. Bottom Apron Replacement

Do not store spare bottom aprons on the bottom rolls, Rolling aprons stored on the bottom roll harden (age) quickly, and are not as flexible as the normal

running aprons. Replace damaged aprons with new aprons using a bonded joint. Do not exceed 10% replaced aprons on the machine. If this occurs before the completion of the normal

life cycle, replace all of the bottom aprons with a new set.

5.8. Guide Arm Pressure

The central air valves control the pressure to all of the guide arms.

The maximum air pressure is limited to 2.3 bar (190 N). This pressure is not recommended for normal usebecause,

The high pressure causes rapid wear of the top roll cots, It increases the forces required to drive the drafting system.

Recommendation – Reduce the pressure to the lowest practical level without increasing ends down or loosingyarn quality.

5.8.1. Cradle Pin Settings

The pin settings (A1/B1 A2/B2 etc.) are shown in the machine manual and should be adjusted according to thefibres and cradles in use.

Avoid placing excessive load on the middle rolls, otherwise early apron damage may occur.

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5.9. Spinning speed curve

To maximize the productivity of the ring-spinning machine, the spindle speed can be increased throughout thebuild. As the balloon size becomes shorter higher spindle speeds can be tolerated with no increase of ends downnor deterioration of yarn quality.

When setting the speed curve it is very important to monitor the ends down rate at the different sections of thebobbin build so as to optimize the speeds and the points of the build at which the speeds can be set.

The following diagram depicts the programmable speed definition points.

With the G 33, a fine tuning of the spindle speed curve is possible due to 4 setting points. Thus an almostconstant yarn tension over the complete cop build-up can be realized.

Speed curve [%]

5.9.1. Start up Speed

(Menu 11.3) Production Settings

The spinning start up speed (point 2) is adjustable between 60% of the maximum spindle speed and 1%

lower than bottom spindle speed (point 3). The spindle speed is gradually increased from the start up speed (2) to the bottom spindle speed (3)

during the building of the base of the bobbin.

5.9.2. Bottom Speed

(Menu 11.4) Production Settings

The bottom speed (point 3) can be set between 1% greater than (2) to 99% of full speed, which is 1%less than speed (4).

The spindle speed gradually increases from speed (3) to (4) during this phase.

The starting position (3) of the bottom speed is the end of cop shoulder (curved base) and has aminimum ring rail position of 46 mm to a maximum position of 1 mm below position (4).

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5.9.3. Top Speed

11.5 Production Settings

The 1st top speed position, point (4) is the start of the 100% of full speed. The lowest setting point is1mm above the point (3) and the latest position is 1mm below point (5).

The 2nd top speed position, point (5) is the end of the top speed phase and has a minimum position of1mm after point (4) to a maximum position of 1mm before full cop position.

Note: The top speed of the machine at start up has to be established by considering the pre sales testdata, customer experience and the ring run - in program. It is suggested that the absolute maximumspeeds be avoided until the machine and components have been run in and the required yarn qualityattained.

The spindle speed is gradually reduced to 95% between point (5) and the full bobbin position (6).

5.10. Bobbin Diameter

The diameter of the full bobbin depends upon the building motion. The machine automatically controls the ring railmovement and will wind a prescribed amount of yarn onto the bobbin according to the setting of “cop weight” –(menu 12.8). The value of (menu 12.8) is an approximation of the cop weight and is to be used only to control thelength of the ring rail cycle and the diameter of the bobbin. When the yarn count is changed at (menu 11.1) thelength of the ring rail cycle will be automatically adjusted. However, re setting of the cop weight can be done tofine tune the bobbin diameter.

5.10.1. Bobbin Base Shape

The bobbin base shape is programmed at the production setting (menu 12.1). If the spinning condition is criticalduring the building of the base, a flat or medium form may be desired to reduce the overall effect of spinning inthis zone. If the spinning conditions are good and enable the round form to be used, an increased amount of yarncan be wound onto the bobbin.

5.11. Spin Out Speed

At full bobbin the machine automatically reduces the speed to a pre-programmed “Spin Out Speed”. Thisvalue can be further adjusted at (menu 13.3). The spin out speed setting establishes the spindle speedat which the machine runs immediately prior to the wind down.

The program calculates the Spin Out Speed to deliver the required “spin-out yarn length” to ensure thatthere is approximately the needed yarn length between the clamp and the traveller. However, theprogram was developed for the mid – range yarn counts Ne30/1 to Ne 60/1. When coarser yarns arebeing spun the spin out speed will need to be manually optimized.

By raising the spin out speed the length of yarn delivered during the wind down operation is increased.Similarly, by lowering the spin out speed the delivered yarn length is reduced.

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The components affecting the required spin-out yarn length are; Tube length,

Ring/bobbin diameter, Wraps around the bobbin, The length of clamped yarn, The length of yarn between the clamp and the traveller.

NOTE: A change of the Spin Out Speed affects:

The yarn length between the clamp and the traveller. If the spin out speed is reduced excessively, the synchronization of the ring rail movement, and the yarn

delivery will be disturbed and the clamping action can be lost. The spin out speed should be changed in small increments to avoid loosing ends during doffing. When the spin out speed is reduced, care should be taken to ensure that it is not too low and causing the

balloon to collapse.

5.11.1. Factors affecting the automatic setting of the Spin Out Speed

Wraps around the bobbin, (menu 12.7) Clamping length, (menu 12.7(2) Yarn length between clamp and traveller, Twist Level during spin out (menu 13.4) Ring rail position to start spindle braking. (Menu 12.9(2)

5.12. Top Bunch Formation

When the machine is at spin out speed the ring rail is raised to the Top Bunch position if so programmed (menu12.6) or, if this is not programmed to 1mm above the full cop position.

5.13. Ring Rail Lowering

The ring rail movement is pre-programmed to complete the lowering and clamping movements to

coincide with the stopping of the spindles and the stopping of the yarn delivery rolls.

The speed of the ring rail lowering motion is depends upon the number of back windings required (menu12.7). The fewer the windings the higher the lowering speed.

5.14. Back Windings on the Bobbin

The number of back windings on the bobbin is set at (menu12.7). It is suggested that the lowest practicalnumber be used number to produce the most direct yarn path from the top of the bobbin to the clamp. A

setting of 1.5 to 2 wraps is preferred unless there are yarn breaks during lowering, in which case the numberof wraps should be increased.

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NOTE: With a change in the number of wraps the program responds to adjust the conditions by making -

- An automatic change in the spin out speed to produce the- Required delivered yarn length for clamping, and- Maintain the synchronization of the system

The setting of the number of wraps is not designed to change the length of clamped yarn or the yarnlength between the clamp and the traveller. However with some materials and spinning conditions theclamping length may vary with a change in the number of wraps.

Care should be taken when changing the number of wraps to use small steps to avoid loosing theclamping action.

5.15. Spindle Brake (Inverter Drive)

The spindles have come to a controlled stop, coinciding with the ring rail arriving at the “cop change position”(menu 12.5/3).

The braking function is activated when the ring rail reaches the “Ring Rail Brake Motor” position (menu12.9/2). The spindle speed is then decelerated at a rate of 16.7n/s² for medium and fine yarns and at10n/s² for yarns coarser than Ne10/1.

The setting of the RR-brake motor position is done to fine-tune the synchronized stopping of the spindleand, when necessary should be done in small steps.

Raising the RR-brake motor position leads to increases in the spin out speed, the yarn delivery speed

and the lowering speed of the ring rail. This leads to a longer time interval between clamping and spindlestop.

Lowering the RR- brake motor position has the reverse effect and reduces the time between clampingand spindle stop.

Care should be taken to be sure that the spindle does not stop before the yarn is clamped. Changes in the brake motor position result in the program raising or lowering the spin out speed

maintain the required “spin out yarn length”

5.16. Twist Reduction / Increase to Improve Doffing and Start of Spinning

The twist level inserted into the yarn during spin out can be controlled by setting the “Yarn twist adjustment duringspin out” (menu 13.4).

For coarse and high strength yarns, it is necessary to reduce the twist during spin out. In the doffingaction it is important that the yarn breaks close to the clamp to avoid long tails and springing yarn.

With such yarns as 100% polyester, it may be necessary to reduce the twist to the 60% level to obtain acontrolled, consistent yarn break.

For fine, low twist yarns it is frequently necessary to increase the twist level so that the yarn is locallystronger for the doffing and start-up operations.

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5.16.1. Twist Change Function

When the twist level during wind down is changed, the new parameters are sent to the deliveryfrequency converter. The speed of the delivery motors run faster or slower in relation to the spindlespeed during wind down. In this way the twist level is changed.

To maintain the required spin out yarn length and delivery speed with a changed twist level, the spindlespin out speed is reduced for the lower twist condition and increased for the higher spin out twist level.

The change of twist level is made when the ring rail reaches the full cops position for the first time.

5.17. Clamping of the Yarn

The ring rail is lowered to below the zero line to open the clamping crown of the SERVOgrip.

The degree to which the clamp is opened is determined by setting “underwinding” (menu 12.7/3). Thenormal setting is 5mm. However, when spinning with “high bow travellers” or coarse yarns a 6mmsetting may be needed.

The ring rail alignment is critical to maintain an efficient function of the clamping mechanism. The length of yarn wound in the clamp is varied by setting the “Length of nipping thread” (menu 12.7/2)

and should be approximately 0.5 to 0.8 turns around clamp. It is necessary to visually check the length of the clamped yarn.

NOTE: The clamped length should never exceed one wrap. The ring rail is programmed to be raised and allow the clamp to close and grip the yarn.

With the Titan and T – flange ring / traveller system, the ring rail normally is raised directly to the doff

position (12.5/3) of 5-8mm above the zero position. With the Zenith / Orbit ring / traveller system the ring rail should be raised to the zero position by setting

“Wait for spindle stop at RR-pos. 0” (menu 13.4/3 –yes). Then, after pausing at position “0”, the ring railis automatically raised to the doff position.

5.18. Yarn Length between Clamp and Traveller

The length of yarn between the clamp and the delivery rollers should be controlled to minimize the snarling of theyarn, but must be sufficient to facilitate the formation of the balloon at spindle start up.

When the machine has stopped for doffing, the display (menu 13.3/2) shows the time between RR pos.0 and spindle stop. This relates to length of the yarn between the clamp and traveller. It is important thatthe yarn does not excessively wrap around the bobbin with the target being 8 to 20 mm, whichcorresponds to 0.1 to 0.6 sec in the display of (menu 13.3/2). This value is a read only value and to beused for information.

The traveller should not come to rest more than half a turn from where the yarn is clamped. To change the length of yarn between clamp and traveller the spin out speed can be adjusted at (menu

13.3). Increased % creates a longer yarn length, Reduced % creates a shorter yarn length.

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Factors that can influence the yarn length between the clamp and the traveller include, The number of back-windings, because the spin out speed is changed to compensate for the

spin out length required. The ring rail position brake motor that establishes the spin out speed. The program attempts to fully compensate for the above changes. However, with some

materials and coarse yarn counts the response is outside the normal parameters and cancause a longer or shorter yarn length.

5.19. Sequence of start up after doff

5.19.1. Pre-Turn of the Spindles

It is possible to pre turn the spindles before moving ring rail or starting to spin. In some cases it is used to orientthe travellers that may have been displaced during the doffing action. This function is activated by programming(menu 13.4/2) – yes.

With the T- flange ring and traveller it is possible that the pre turn function will have an undesirable effectand will increase the tendency for the yarn to come out of the traveller and reduce start up efficiency. Inwhich case it should be programmed to “NO”

5.19.2. Snarl Elimination

To remove the snarls in the stationary yarn, the ring rail is raised and then lowered at controlled speeds prior tothe start of spinning.

The ring rail is raised to a height set at Lift Reversal Point for snarl removal (menu 12.3/2). It is usual toraise the ring rail to a height of 50 to 80mm.

The speed of the upward movement is set at (menu 12.4/1) and a normal speed is 30 to 35 mm/sec After reaching the reversal point, the ring rail is reversed and lowered to the “Start Spinning Position”

which is set at (menu 12.2/1). A normal value for the start spinning position is 50 mm. This is set tominimize the initial spinning tension and wind the initial yarn within the first layers of the build.

The downward speed of the ring rail is set at (menu 12.4/2) and normally falls within the range of 35 to45 mm/sec.

5.19.3. Start Spinning

RR moving Downwards: The spinning operation is normally started while the ring rail is movingdownwards (menu 12.2/2) after leaving the Snarl lift reversal point. The “start spindle” position is set bythe ring rail position (menu 12.2/1) at 10 to 30mm below the reversal point.

RR moving Upwards: When the snarl elimination is not needed, the ring rail can be moved directly tothe “start spindle” position (menu 12.2/1) at 20 to 30mm and the setting of the (menu 12.2. / 2) should be“Upwards”. With this arrangement the Snarl lift position setting (menu 12.3/2) should be 25 to 30 mm.

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5.20. Optimization of the doffing process

5.20.1. Prior to doffing, when the yellow light is on and the travelling cleaner is parked

Record the positions and number of ends down or, Piece up all ends so that there are no ends down prior to doffing. Feel the balloon tension when the spindles are running at spin out speed as the last layer is being

wound. Check to feel if the tension is too low.

5.20.2. During the Stopping Action

Observe and manually check the movements and STOPPING of the delivery roll and the spindle. Theyshould be synchronized.

Observe the balloon to see if it collapses during down winding.

5.20.3. During the Doffing Action

When the doffer starts to move, activate the EMERGENCY STOP. Record the ends down to determine the breaks during lowering. Check the position of the traveller relative to the SERVOgrip.

Over 20mm is too high for the Titan ring and traveller, Over 15mm is too high for Zenith, Orbit or T-flange rings.

Feel the yarn tension between the delivery rolls and the thread guides, Tight yarn means that the yarn between clamp and traveller is too short, Loose and snarling means that the yarn length is too long, The Optimum is with the yarn “not tight” - Preferred snarl of 3 to 5mm.

Re-start the machine. Stop the doffing action when the bobbins have been removed and the ring rail has swung out and is

lowering the bobbins. Stop the machine with the STOP button. Record the ends down to see how many were created during the doffing step. Note the nature of the yarn breaks.

Are the yarns broken uniformly and close to the clamp?

Is the yarn tail too long and winding around the spindle? Did the yarn break and “spring back”? Have any yarns come out of the traveller? Check yarn length in the clamp. Is the yarn clamped correctly?

Re-start the machine and allow the doffer to function and start spinning. Carefully observe the snarl removal and balloon formation

5.20.4. After Start of Spinning

Stop the machine as the doffer rail is returning to the ground position.

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Technology Handbook

Record the number of ends down of which the yarn is broken and no remaining yarn is visible. Some of thebroken yarn may have been wound onto the spindle and be under the tube. In this case the yarn clearly

broke during starting. Record the number of ends down with yarn on the thread guide (pigtail). This indicates that the balloon

collapsed or that the balloon came out of the traveller. NOTE: If the machine is in the set-up mode and only a few positions are being used for spinning, return the

tube-transporting belt to the ground position before re-starting the machine. If there are obvious problems with the doffing efficiency, analyze the data collected and decide on what

changes of settings or travellers are needed. If immediate changes are required and an addition test performed, the changes should be made before the

machine is started. Start the machine and spin on to the positions with ends down. When a small amount of yarn has been spun onto the bobbins, program the machine to make a “Premature

Doff” at (menu 13.1 yes) in the maintenance mode.

Check to see the effect of the changes and proceed as necessary.

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10. Rotor Spinning


1.1. Introduction 4

1.1.1. Applications 4

1.1.2. Rotor yarn advantages 5

1.1.3. Rotor yarn disadvantages 5

1.1.4. Rieter rotor spinning product lines 5

1.2. Principle Features 6

1.2.1. R 20 Machine features 6

1.2.2. BT Machine features 6


2.1. Application guidelines 8

2.1.1. Cotton knitting yarns 8

2.1.2. High strength cotton weaving yarns 8

2.1.3. Cotton / polyester weaving yarns 9

2.1.4. Denim yarns 10 2.1.5. Drapery and upholstery yarns 11 2.1.6. Polyester weaving yarns 11 2.1.7. Acrylic yarns 12 2.1.8. Coarse count cotton yarns 12

2.1.9.

Viscose/rayon yarns 13


3.1. Technological guidelines 14 3.2. Rotors 14 3.2.1. Influence of rotors diameter on yarn characteristics 14 3.2.2. Influence of rotor groove 14 3.2.3. Influence of surface coating 15 3.2.4. Influence of rotor speed 15 3.2.4.1. Spinning tension 15 3.2.4.2. Production 15

3.2.4.3.

Yarn elongation and winding tension 16

3.2.5. Factors influencing the spinning tension 16

3.2.6. List of R 20 rotors 16 3.2.7. Rotor speed limits 17 3.3. Yarn twist 18 3.3.1. Recommended twist multipliers 18 3.3.2. Influence of twist multiplier 19 3.3.3. Twist insertion 19 3.3.3.1. Actual twist 19 3.3.3.2. False twist 19 3.4. Nozzles 20

3.4.1.

Steel nozzles 20

3.4.2. Ceramic nozzles 21 3.5. Rotor, faceplate, nozzle combinations 22

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3.6. Opening rollers 22 3.6.1. Opening roller wire 22

3.6.2.

Standard opening roller and applications 23 3.6.3. Coated opening rollers 24

3.6.4. Lifetime of opening roller wire 24 3.6.4.1. Definition of lifetime 25 3.7. Opening roller housing 26 3.7.1. Trash removal 26 3.8. Draft 26 3.8.1. Influence of draft 27 3.9. Winding 27 3.9.1. Important winding settings and parameters 27 3.9.2. Cradle alignment 28 3.9.3. Yarn traverse 28

3.9.3.1.

Thread guide stroke 28

3.9.3.2. Variable stroke gear box 28 3.9.4. Stroke displacement 28 3.9.5. Winding angle (Helix angle) 29 3.9.6. Winding tension 29 3.9.7. Package cradle pressure 30 3.9.8. Antipatterning 30 3.9.9. Recommended maximum package diameters 31 3.9.10. Yarn delivery top roller 31 3.9.11. Winding speed 32 3.10. Waxing 32 3.11. Piecing 33 3.11.1.

Piecing systems 33

3.12. Online quality monitoring 33


4.1. Overview of preceding processes 34 4.1.1. Bale laydown 34 4.1.1.1. Cotton 34 4.1.1.2. Synthetic fibres 34 4.1.2. Blowroom 34 4.1.3. Carding 35

4.1.4.

Drawing 35

4.1.4.1. Sliver quality 36 4.1.4.2. Sliver evenness 36 4.2. Start up steps 37 4.2.1. Basic pre start up checks 37 4.3. Air requirements 38 4.3.1. Compressed air 38 4.3.2. Exhaust air / suction 38 4.3.2.1. Waste removal 39 4.3.3. Room conditioning 39


5.1. Machine handling 40

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Technology Handbook

5.2.1. End down analysis 41 5.2.2. Typical ends down list 42

5.3.

Procedures to re-start positions with red lights 42 5.3.1. RIETER R20 “OPERATOR REDLIGHT CHECKLIST” 43

5.4. Fly and dust accumulation at the feeding zone 44 5.5. Application of Barco yarn clearer with polyester yarns 45 5.5.1. Facts we need to know about Barco yarn clearing: 11 Points 45 5.5.2. Function of static dust monitoring 49 5.5.2.1. Function of dynamic dust monitoring: Small contamination 50 5.5.2.2. Function of dynamic dust monitoring: Large contamination 51 5.5.3. With PES, three completely different problems must be held apart: 52 5.5.4. Why does the Vminus-channel cut after a yarn break? 53 5.5.4.2. Measurement to prevent V-cuts 54 5.5.5. How does the dynamic dust monitoring function? 55

5.5.5.1.

Explanation to dynamic dust monitoring: 55

5.5.5.2. How can we improve this disadvantage? 56 5.5.5.3. Assessment of these measures: Does the dust management function? 57 5.5.6. Practical examples 57 5.5.7. Summary 59

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1.1. Introduction

Rotor spinning has evolved over the past 35 years to dominate some markets. The productivity, conversion costsand yarn characteristics have made it possible for the rotor spinning market to grow. This growth has beenachieved by replacing some ring spun yarns, but, because of the yarn structure, the applications are limited.Rotor yarns are primarily spun from the “carded yarn” preparation system into the count range Ne 3/1 to Ne 36/1with a few finer exceptions.

1.1.1. Applications

Rotor yarn is successfully used in both weaving and knitting applications even though the yarn strength is lowerand the handle is harsher than ring spun yarn.

Typical applications include: Primary fibres:

Mop yarns - Cotton waste,Carpet backing Polypropylene,

Blankets - Acrylics,Upholstery Cotton, synthetics and blendsDraperies and wall coverings Synthetics and blends

Gloves Cotton

Sweaters Acrylics and cottonSocks Cotton, acrylicsDenim Cotton,

Towels Cotton, polyester cotton

Napery, table wear Polyester/cotton blendsWoven apparel, trousers / shirts Cotton and pes/co blendsSports wear, fleece fabrics Cotton, acrylics and pes/co blends

Sheeting Cotton and pes/co blendsUnderwear Cotton

T- Shirts Cotton and pes/co blendsKnitted shirts and dresses Cotton and pes/co

Shirts (leisure), blouses, dresses Viscose, lyocell, tencelLinings (suits, trousers) Viscose

Knitwear (woman) Viscose/pes blendsIndustrial fabricstapes and abrasive cloth

Polyester

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1.1.2. Rotor yarn advantages

The primary advantages of rotor spinning over ring spinning are increased production rate, reduction ofprocesses such as roving and winding, ease of automation, reduced labour requirement and lower productioncosts. In addition to the economic benefits, rotor yarns have advantageous characteristics, which include:

• lower defect levels compared to the other spinning systems, particularly fewer yarn long thick and thinplaces,

• superior knit fabric appearance,

• lower fibre shedding at knitting or weaving than ring spun yarn,

• less torque than ring spun yarn,

• less energy required than for ring spinning,

• less floor space required compared to ring and air jet spinning,

• sophisticated real time quality and production monitoring on each spinning position,

•

superior dye-ability compared to ring spun yarn.• (Short staple yarn manufacturing –McCreight of ITT)

1.1.3. Rotor yarn disadvantages

From the introduction of rotor spinning the stiffness and harshness of the yarn has been of concern. The yarnassembly is bound together by fibres that are tightly wrapped around the bundle producing a less flexible product.Extensive efforts have been spent to minimize this effect, but it is not possible to eliminate all wrapping fibres. Associated disadvantages include:

• lower strength when compared to ring spun yarn, (approximately only 70% of comparable ring spun yarn),

• high pilling propensity compared to air jet yarn,

• accelerated needle wear at knitting compared to ring spun yarn,

• high maintenance costs compared to ring and air jet spinning.

• (Short staple yarn manufacturing – McCreight of ITT)

It is clear that rotor yarn is not the best for all applications. However, there are a great number of technologicalvariations available that make a rotor spinning machine very versatile in terms of fibres that can be processed,yarn counts that can be spun and yarn characteristics that can be produced.

1.1.4. Rieter rotor spinning product lines

Rieter produces two different types of rotor spinning machines.

R 20 rotor spinner

In the R 20, the rotors are supported by indirect bearings that enable the rotors to turn at speeds up to 140,000rpm. Additionally, a fan at the end of machine generates the air used to transport the fibres from the openingroller to the rotor.

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BT rotor spinner BT rotor(with air pumping action)

In the BT rotor spinning machines, therotor shafts are mounted in direct bearings thatlimit the speed to a maximum of 105,000 rpm. Additionally, the fibre transport air is primarilycreated by the pumping action of the rotors thathave holes at the periphery to pump air as therotors rotate.

1.2. Principle Features

The following section describes the features of Rieter’s Rotor spinning machines as described to customersthrough the sales and marketing information.

1.2.1. R 20 Machine features

Rotor sizes from 28 to 56 mm diameter, Rotor speeds up to 140,000 rpm depending upon rotor diameter, yarn count and types of fibres being spun, Indirect Bearings for high speed spinning, AERObearing for the axial support of the rotor shaft, Delivery speed – up to 220 m/min for conical and cylindrical packages,

Raw material – cotton, man-made fibres and blends up to 60 mm length, Yarn count range – 125 to 10 tex: Nm 5 to 100 or Ne 3/1 to 60/1, Draft range – 40 to 400 depending upon yarn count, Efficient rotor cleaning system with high pressure air jets, SYNCRO TOP piecing system for optimal piecing quality at high take-up speeds, Quality monitoring and foreign matter detection, “Jumbo“ – Packages up to 5 kg or 340 mm diameter Cylindrical packages up to 340 mm diameter, conical packages of 1º51´, 3º51´or 4º42´ up to 270 mm

diameter, Package winding with a Variable Stroke Box (VSB) with pneumatic package loading to improve package

build, density and yarn unwinding characteristics, REDIpac yarn end location for easy handling at downstream processes, UNIfeed “Just in time“ tube supply system.

1.2.2. BT Machine features

Rotor sizes from 26 to 66 mm diameter, Rotor speed up to 105, 000 depending upon rotor diameter, Direct bearing, now available with ceramic balls, Axial gearing not needed, Delivery speed – up to 180 m/min for cylindrical and conical packages, Fibres – cotton, flax, regenerated fibres, man-made fibres and blends,

Yarn count range – 200 to 14.5 tex: Nm 5 to 68 or Ne 2.5/1 to 40/1, Draft range – 21 to 300 depending upon yarn count,

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AMISPIN semi automatic piecing on the BT 903, Fully automatic piecing on the BT 905,

CCD yarn clearer and quality monitor, Cylindrical packages up to 4.15 kg or 300 mm diameter, Conical packages up to 2.4 kg or 270 mm diameter, Integrated robot for cleaning, piecing and doffing on BT 905, Just-in-Time tube transportation.

For both the R 20 and the BT machines, it should be understood that production speeds and spinning conditionsare dependent upon the yarn quality required, the material being supplied and the spinning room conditions.

Also, maximum production limits of speed or yarn count can only be attained when suitable raw material isoptimally processed prior to spinning. Additionally, the correct spinning components of good quality have to beused.

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2.1. Application guidelines

This section aims at providing information regarding the spinning requirements for various endproducts.

2.1.1. Cotton knitting yarns

Knitting yarns Ne 16/1 to 30/1 (Nm 27 to 50) should be spun with a relatively low twist level,TM 3.2 to 4.0 (α m 97 to 120, to produce flexible yarns.

Rotors of 35 mm Ø at up to 100,000 rpm, 31 mm Ø up to 115,000 rpm or 30 mm Ø up to125,000 rpm can be used when the cotton is well prepared.

With the 35 and 31 mm rotors the K4KK, the K8KK or the KSS nozzles are used. For high speed spinning with the 30 mm rotor the K6KF nozzle is proving to be successful. The soft twist tubes are always used to help stabilize the spinning condition. It must be emphasized that the rotor speeds are dependent upon the quality of the cotton and

the preparatory processes. To produce a softer, more bulky yarn with more hairiness, the fluted grooved nozzle, K4KS

can be used, but the rotor speed may have to be reduced to obtain a stable spinningcondition.

The OB 20 opening roller is normal, but the OB20 DN, the OB20 /4 DN or the OU25D canalso be used to extend the opening roller lifetime if the cotton tends to be abrasive.

Two processes of drawing are preferred, but single drawing is acceptable if there is goodcontrol of the card and drawing sliver weights.

Knitting yarns must be well waxed. Yarn quality monitoring is strongly recommended, but it is recognized that for some products

it is not absolutely necessary. In any event the piecing quality should be optimized to producea small piecing that will not create problems at the knitting needles.

2.1.2. High strength cotton weaving yarns

Weaving yarns have to be able to withstand the actions of high speed weaving machines.They should be strong and as smooth as possible with a low level of hairiness.

Normal twist level is TM 4.5 to 5.0 (α m 135 to 150) The spiral nozzle KS is preferred, but sometimes the K4KK is used. Also the soft twist tube is

advantageously used for the spinning of finer yarns. The rotor diameter depends upon the yarn count being spun, but the rotor groove should be

selected to meet the end use requirements. The SD or MD grooves are normal for themedium and finer yarns, whereas a more open groove may be needed for trashy cotton usedto spin coarser yarns.

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Rotors of 30 mm Ø at up to 125,000 rpm,31 mm Ø at up to 120,000 rpm,

35 mm Ø at up to 100,000 rpm,40 mm Ø at up to 80,000 rpm.

The piecing should be as strong as possible, but not so large as to be fabric defects. Quality monitoring is strongly recommended.

2.1.3. Cotton / polyester weaving yarns

Cotton / polyester weaving yarns are normally spun into the count range Ne 10/1 to 40/1 (Nm 17 to70)

and are spun from blends that are from 80% cotton / 20% polyester to 75% polyester / 25% cotton.With the exception of the rotor coating, the blends can be treated in a similar manner.

The yarns must be strong and smooth with minimal imperfections that would be seen asfabric defects.

The twist level does not greatly affect the yarn strength, the twist /strength curve is relativelyflat. Consequently the twist level is established on the basis of spinning performance and endproduct requirements. The normal twist is TM 3.2 to 4.0, but being slightly higher for cottonrich blends and lower for polyester rich blends.

To prevent damaging the polyester, nozzles with a small radius are used to allow spinning athigher rotor speeds. This is particularly the case for polyester rich blends. For high speedspinning the “flat” type nozzles S3KF or S6KF are frequently used. The K3 KF nozzle is also

being used for with compatible polyester. For some of the coarser yarns, being spun onlarger rotors at slower speeds, the grooved ceramic nozzle is frequently suitable.

The soft twist tube frequently used to help stabilize spinning. The staple length of the polyester influences the minimum rotor diameter. It is not normal to

use rotors smaller than 31 mm Ø. Where the polyester fibre finish is compatible with highspeed rotor spinning the:

31mm rotor is being used at speeds of over 115,000 rpm and the35mm rotor is being used at 100,000 rpm.

It should be noted that the polyester fibre finish is critical to the spinning performance.

For cotton rich blends the diamond (D) rotor coating is recommended and for the polyesterrich blends the boron (B) coating is best.

Blend yarns are normally spun with lower twist levels, therefore, it is very important that thecotton trash content of the blend be controlled to below 0.05%. Large trash particles tend tolodge in the rotor groove and interfere with spinning.

The opening roller wire is normally OS 21/ 6 DN or OS 21. In some cases, after pre-salestests, the OU 25-D wire may be specified.

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2.1.4. Denim yarns

Denim yarns now cover a wide range of applications from traditional cotton “Jeans fabric” producedfrom Ne 5.6/1 to ladies fashion shirts produced from Ne 22/1 and finer. Denim was originally definedas woven, cotton, fabric produced from an indigo dyed warp and a natural coloured filling and most ofthe yarn counts fell between Ne 5.6 and 12/1.For the yarns finer than Ne 12/1, the processing comments are covered in the section 6.2 - coveringcotton weaving yarns.

The warp yarns used for the indigo dyeing process and the subsequent re-beaming operation have tohave a low “cling” tendency. This is not the case for filling yarns nor for yarns going into the naturalwarps or beam dyed warps.Many spinners choose to produce yarns that can be used for all applications, but the result may be acompromise of the fabric appearance.

The filling yarn must be uniform in appearance from the inside of the package to the outside.There should be no rotor loading that changes the yarn hairiness from a clean to loadedcondition. Filling variations are very obvious when used across a dyed warp and areconsidered as defects.

The warp yarn is not sensitive to slight yarn variations. In many instances, a “ring like”uneven appearance is desired.

Rotors for coarse and medium count yarns have been developed with a wide-angle groove tominimize rotor loading and subsequent yarn variations. The D lll rotor is frequently used forspinning denim yarn. For cotton that is very abrasive, boron treated steel with a diamond /nickel coating is recommended.

For rope dyeing warp yarns the following rotors are suggested:Ne 5,6/1 to 12/1 - rotor 48 D lll D at 50,000 to 65,000 rpm.Ne 5.6/1 to 12/1 - rotor 40 D lll BD at 60,000 to 80,000 rpm.Ne 6/1 to 12/1 – rotor 35 D lll BD at 75,000 to 90,000 rpm.

In some cases the D lll rotor is used for beam dyed warps and filling to simplify the logistics ofthe spinning plant.

Where a strong, lean yarn with low hairiness is needed for filling or beam dyeing, the 40 mm S Drotor is suggested.

Denim yarns are normally spun with grooved ceramic nozzles, depending upon the required yarncharacteristics. The spiral nozzle is not recommended because the coarse yarns are too livelyand have excessive torque. The K3KK, K4KK, K8KK and K4KD are normally used. When the

K4KD nozzle is used, the yarns go into rope dyed warps. Lively, coarse denim yarns tend to kink and snarl at the next process. To overcome this

tendency, the soft twist tube can be used. However it should be noted that this tube tends toslightly increase the yarn bulk and hairiness.

The opening roller wires used for denim yarns normally are standard for cotton i.e. OB 20,OB 20 – DN or OU 25 D. These wires produce a uniform yarn with good evenness.

“Ring Like” denim yarn is a relatively uneven yarn created by irregular fibre opening. This effectcan be produced by using a special opening roller that can be made available through thetechnical department.

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2.1.5. Drapery and upholstery yarns

Drapery and upholstery yarns are frequently spun from synthetic fibres, nylon, polyester, acrylic andviscose in 100% form or as blends with a variety of fibres to obtain a special texture or optical effect:

Fibres tend to over 1.5″ long and of relatively coarse denier. The hardened steel 56 mm rotors with 57-degree grooves are frequently used, - (65 mm for special applications). For 1.5″ fibres the 40 SB rotor issuitable.

Yarn counts are in the range Ne 3/1 to 6/1 Care has to be given to controlling the feeding of the sliver. If the sliver is too cohesive and will

not open easily, the sliver feed is irregular and spinning is unstable. Attention has to be given toprevent the sliver slipping between the feed roller and the feed plate. The fluting of the feed rollershould securely grip the sliver.

The opening roller should have a wear resistant coating or be of the wear resistant pinned ringtype.

The nozzle has to be selected depending upon the type of fibres being spun. In some cases theK4K nozzle is used and in others instances, for 100% polyester, the smooth flat steel nozzleSGF is used.

Many times the spinning components for these products have to be selected by the business unittechnical department.

2.1.6. Polyester weaving yarns

These yarns are normally for technical fabrics that have high performance requirements. They areused in tapes, belts and substrates and composites. Care has to be exercised to obtain the maximumpossible yarn strength. This means that the fibres should not be damaged in the opening area or atthe nozzle. Suggestions are:

The rotor diameter has to be selected according to the count being spun, i.e. 40 mm SB rotor forNe 8/1 to 16/1 and 35 mm or 31 mm SB rotors for finer yarns.

The hardened steel or boron treated steel rotors, SB, are recommended for 100% polyester. The nozzles should have a low false twisting action. The flat type nozzle is recommended. The

smooth nozzle SGF is suggested as the least aggressive nozzle. When a slightly higher level offalse twist is needed the grooved nozzle S3KF is sometimes used.

The soft twist tube may be needed to improve the spinning stability, however it may result in a

reduction of yarn strength. The opening roller wire is frequently difficult to select. The uncoated OS 21 wire does the least

damage to the fibre and is the best surface if it has an acceptable lifetime. However, thepolyester may have a finish that is abrasive and this tends to wear out the wire in anunacceptable short period of time.

Coated opening roller wire such as OS 21 /6 DN may improve the lifetime, but the fibre may bedamaged by the diamond coating and create dust build up in the rotor groove. To minimize fibredamage the opening roller speed should be as low as practicable. Additionally the feed plateshould not over control the fibres increasing the fibre opening forces.

In some cases the needle-opening roller has proved to be the best for certain applications.Check with the business unit.

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2.1.7. Acrylic yarns

Acrylic yarns are used for a variety of products from knitted apparel to industrial awnings andsubstrates. Most of the acrylics are either dyed fibre, package dyed, or piece dyed as fabric. Acrylicsare normally compatible with rotor spinning, but some of the end products have to be high in lustre,soft and bulky. This is a challenge in rotor spinning because of the yarn structure and wrapper fibres.

For knitting yarns, the wrapper fibres should be minimized. Larger rotors and open grooves(57 degree rotor) are preferred. The softest yarns are produced with 56mm, 48mm and40mm rotors if the spinning economics are acceptable.

Yarns can be spun using the 35mm and 32mm rotors, but the yarn will be compact andsomewhat stiff.

The nozzle has to be selected to meet the end use requirements. Sometimes the groovednozzle such as the K4KK is good for producing a hairy yarn under a stable spinning

condition, but unfortunately the yarn may shed badly in the knitting machine. This effect ispartially dependent upon the fibre finish. In any event the fibre should be producedspecifically for rotor spinning.

A smooth nozzle is frequently preferred for acrylics. The soft twist tube may be necessary to improve the spinning stability and allow low twist

yarns to be produced, however, the hairiness will be slightly increased The OS 21 opening roller works well. The diamond-coated wire tends to damage the fibre

and cause shedding on the machine. The yarns that are going directly to the knitting machine have to be waxed at spinning.

Knitting yarns that are going to be package dyed should not be waxed until after the dyeingoperation.

2.1.8. Coarse count cotton yarns

For coarse count yarns in the range Ne 3/1 to 6/1 care has to be taken in selecting the correctspinning components, robot elements and the package changing parts:

Diamond coated 56mm rotors. Ceramic grooved nozzle with a large diameter hole to allow the coarse yarn to pass easily. Diamond coated opening rollers such as OB20 DN to resist wear. The robot has to be set to produce a controlled piecing which will not be so large as to choke in

the subsequent operation. The package transfer system has to be capable of handling the coarse yarns. It is very important

that the appropriate hardware be used to ensure that the yarn end is cut at yarn transfer.

The machine length should be limited in spinning positions so that the robot can effectivelyhandle the functions of piecing and package changing. When spinning very coarse yarns, thetime to wind a package can be as short as two hours, which limits the number of positions, thatone robot can efficiently handle.

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2.1.9. Viscose/rayon yarns

Viscose was one of the earliest fibres to be spun on the rotor spinning because it did not contain trashand it was not temperature sensitive. However care has to be taken to optimize the machine for highperformance spinning.

The rotor diameter depends upon the yarn count and the staple length. Viscose can be spunon rotors of any diameter, from 28mm to 56mm.

The rotor surface should be hardened steel or boron. Rotor speeds can be relatively high if the fibre is produced with a finish for high speed rotor

spinning:

48 mm up to 70,000 rpm,40 mm up to 80,000 rpm,

35 mm up to 95,000 rpm,31 mm up to 115,000 rpm30 mm up to 125,000 rpm

The “S” rotor groove is used to produce a strong uniform yarn. The nozzle has to be selected according to end use requirements. Some applications need

the smooth nozzle while others need the grooved nozzle. The OB20 DN or the OB20/4 DN opening roller wires are commonly used. In plants where

various types of fibres are spun, the OS21/ 6 DN can also be used for viscose.

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3. Machine Elements

3.1. Technological guidelines

The following section covers the normal applications of spinning components used with common fibres andblends. It should be understood that when exceptions are encountered, the Business Unit R should be consulted.

3.2. Rotors

Rotors have to be carefully selected to meet the production and quality expectations. The primary considerations

are:

Yarn type, - for example knitting, weaving, and denim. Yarn count, - small rotors can be used for fine counts but larger rotors are needed for coarse counts. Fibres to be spun, - the speed at which fibres can be spun may determine the rotor size. Small rotors have

minimum speeds that may exceed the tolerable speed of the fibre. Fibre length - this limits the minimum rotor diameter. Long fibres cannot be spun using small rotors. Fibre type – cotton can be spun using diamond coated rotors whereas, polyester and some blends spin

better using boron treated rotors. Sliver trash content – high trash content requires a rotor groove that is self-cleaning or not sensitive to trash

build up.

3.2.1. Influence of rotors diameter on yarn characteristics

The rotor diameter, groove, surface finish, and speed affect the yarn formation and yarn characteristics in thefollowing ways:

the larger the rotor diameter relative to the fibre length, the fewer will be the “wrapper fibres”. wrapper fibres increase with the use of smaller rotors, larger rotors produce a more flexible yarns, with larger rotors a yarn of lower twist can usually by spun, larger rotors can produce softer yarns.

3.2.2. Influence of rotor groove

The radius of the bottom of the groove primarily affects the compactness of the fibre bundle before it istwisted into a yarn. High strength, lean yarns can be made with small radius grooves.

Grooves with a small radius tend to trap trash particles. This can lead to moiré or rotor loading. The groove angle affects the way the entering fibres are embodied into the fibre bundle and the yarn. With

large angle grooves the incoming fibres tend to slide under the yarn being formed and hence reduce thenumber of wrapper fibres. This phenomenon is also affected by the orientation of the groove relative to thesliding wall of the rotor.

With large angle “open” grooves coarse can be effectively spun, such grooves are used for Denim andcoarse knitting yarns.

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3.2.3. Influence of surface coatingThe use of wear resistant coatings to extend the lifetime of rotors is now a common practice. However one

coating is not suitable for all fibres.

Diamond coating with a nickel topcoat is the most common treatment and is used for cotton and cotton richblends with polyester.

The nickel topcoat is used to limit the exposure of the diamond particles and minimize the aggressive actionof the diamond.

For extra wear resistance, the basic steel rotor may be boron treated to produce a very hard surface beforethe diamond / nickel coating is applied. This process is used for some coarse yarns such as denim.

Boron treatment of the rotors is now used extensively to extend the li fetime of rotors used to spin syntheticfibres, polyester rich blends with cotton, and viscose.

Hardened and tempered steel rotors are used on some of the larger rotors to spin a wide range of fibressuch as cotton, polyester / cotton blends, synthetic fibres, viscose and regenerated fibres.

3.2.4. Influence of rotor speed

3.2.4.1. Spinning tension

The rotational speed of the rotor generatescentrifugal forces (F 2) at the rotor groove. Theseforces increase with the speed and fibre mass.

To remove the yarn from the groove the centrifugalforces have to be overcome by the yarn strength.

Additionally, the yarn has to be pulled over thenozzle that creates a dragging resistance as falsetwist is imparted.

The yarn tube and the “Soft Twist “ devices createresistance and increase the overall withdrawalforce, referred to as the spinning tension (1)

3.2.4.2. Production

The rotor speed is the speed of twist insertion; each revolution of the rotor is one turn of twist. As the rotor speedis changed, the delivery speed changes when the twist level is constant.To increase productivity, smaller rotors have been developed to run at increased speeds of up to 140,000 rpm.However, small rotors can only be used to spin medium and fine yarns.

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3.2.4.3. Yarn elongation and winding tension

As the rotor speed is increased the spinning tension increases. This increase in tension below the delivery rollextends the yarn and consequently reduces the remaining yarn elongation. Higher speeds ►Lower yarnelongation.

It should be noted that if the rotor speed of a machine is changed, the spinning tension changes. The windingtension may need adjustment to compensate for the change of residual yarn contraction. An increase in rotorspeed can result in the winding tension being too high.

3.2.5. Factors influencing the spinning tension

The spinning tension is influenced by: Rotor speed, - Higher speed with same rotor diameter ►increased spinning tension, or reduced speed

►lower tension Rotor diameter, - Smaller rotors at the same speed produce lower spinning tension. Yarn count – An increase in count or fibre mass increases the spinning tension. Nozzle – a more aggressive nozzle increase the spinning tension.

Fibre finish – A change of fibre finish can change the frictional drag as the yarn passes over the nozzle. Thespinning tension will be changed.

“Soft Twist” tube - imparts a slight false twisting action and increases the spinning tension.

3.2.6. List of R 20 rotors

DIII = for denim warp (rope dyed)

S = Standard groove

R = for recycled fibres

M = for knitting yarns N = for cotton with high trash content

For identification purposes, the backs of the rotor cups are marked.

Diameter - 28 to 56 mm,groove (type) – S, M, N, Dlll or R,coating – B boron,- D - diamond, V – hardened and tempered,coded manufacturing date.

Example: 31- M- D N38

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3.2.7. Rotor speed limits

Each rotor size has an optimal speed range depending upon the fibres, yarn count and nozzles. It is suggestedthat at start up a mid range speed be initially used until the machine and components are run in.

• Exceeding the maximum speed➯Spinning tensions are too high and the yarn tends to break. A small portionremains in the rotor.

• Being under the minimum speed➯Spinning tension too low. This results in an unstable spinning condition. Atan end down, the yarn end will be tapered.

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3.3. Yarn twist

The yarn twist is needed to give stability to the yarn and enable the yarn to be formed and wound. The level oftwist is usually established dependent upon the yarn requirements of:

strength, processing needs for weaving yarns, fabric softness for knitting yarns, the fibres being spun influence the level of twist. Longer fibres need less twist than short fibres. Twist Multiple (TM.) or α has been established as a value to maintain similar yarn characteristics when the

count is changed.

For the Ne and Nm systems of yarn count, the formulae for twist is:

Tpi = TM x Ne

T/m = αm x Nm

The twist in the yarn is the rotor speed divided by the delivery speed.

T/m = Rotor rpm Tpi = Rotor rpm

Delivery speed m/min Delivery speed m/min x 39.37

3.3.1. Recommended twist multipliers

Suggested twist multiple ranges for rotor yarns for various applications:

m e

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3.3.2. Influence of twist multiplier

3.3.3. Twist insertion

3.3.3.1. Actual twist

The actual twist of rotor spun yarn corresponds to the rotation of the rotor. However, because of the yarnstructure it is not possible to measure the amount of twist using standard “twist-untwist” lab testing methods.

The lab twist values are always less than the actual twist. The higher the degree of fibre orientation and thefewer the wrapper fibres, the closer will be the lab twist values to the actual twist.

3.3.3.2. False twist

As the spun yarn is removed from the rotor, it is pulled through the stationary nozzle. The yarn partially rollsover the nozzle surface and false twists the yarn. The false twist extends back to the yarn peeling point in therotor groove. The false twist does not stay in the yarn as it leaves the nozzle. The false twisting rolling actionis greater when any of following are increased:

the nozzle surface friction, the size of the nozzle contacting surface, the form of the nozzle surface, i.e. Grooved, spiral, and shape, spinning tension, yarn count

The combination of actual twist and false twist determine the amount of “spinning-in” twist at the peeling point. Insufficient spinning- in twist produces an unstable spinning condition and the ends down level will be

high. The yarn end will have thin tailing out end. Excessive spinning-in twist creates a high amount of fibre disturbance. This can result in a rough hairy

yarn. The optimum level of spinning-in twist is frequently established by trials.

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3.4. Nozzles

As previously mentioned, the nozzle is important in maintaining a stable spinning process and in the production ofa desired yarn. The following chart illustrates some principles in nozzle selection.

Effect of nozzle surface

Low false twist High false twist

Minimal action Increased action

Smooth nozzle - Low friction Grooved

Smooth yarn Low ends down

Strong yarn Hairy yarn

High twist yarn Bulky yarn

Low pilling Tendency to pill

Low scuffing low CV% Higher CV%

3.4.1. Steel nozzles

Steel nozzles are recommended for temperature sensitive fibres such as polyester, acrylic and polypropylene. Insome applications they are not wear resistant and need to be replaced after only a few months of use.

Note: Worn nozzles affect yarn quality and spinning performance. Steel nozzles should be carefully monitoredand replaced in a timely manner.

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3.4.2. Ceramic nozzles

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3.5. Rotor, faceplate, nozzle combinations

In the R 20 the plug in type nozzles are now used for rotors up to 48-mm diameter.

Rotor Faceplate Nozzle

D 28

D 30D 30

D 31

D 32

D 35

D 32

D 40

D 48 D 40

D 28 to 48(plug in nozzle

D 56 D 56 D 56 (screw in nozzle)

3.6. Opening rollers

The function of the opening roller is to separate the fed fibres so that they will pass as individual fibres down thefibre channel into the rotor. The opening action is very intensive and can damage fibre if the incorrect wire orspeed is used. This is particularly the case when synthetic fibres are being spun.Worn or damaged opening roller wire causes yarn quality problems and high ends down.

3.6.1. Opening roller wire

The opening roller wire has been developed to effectively open the fibres at the feeding zone and release thefibres into the fibre channel. The wire type and speed should meet the following requirements:

Open the fibres at the feeding zone. Minimize fibre damage in the opening action. Avoid overheating synthetic fibres. Some fibres can be easily fused by an over aggressive opening roller

action.

Release “foreign matter” at the trash removal area, Release the fibres at the fibre channel so that a uniform fibre flow is achieved. Avoid fibre lapping around the opening roller. Increasing the leading angle, of the wire ►

Increases the opening action. For cotton the OB 20 wire is used with a front angle of 25 degrees.Increases the chance of fibre damage. For cotton / polyester the OS 21 wire type is used with 12

degrees. Increases the tendency for fibres to wrap around the opening roller. Increasing the tooth spacing can –

Improve yarn imperfections,Reduce the level of ends down.

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3.6.2. Standard opening roller and applications

The following is a list of the R 20 opening roller wire types.

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3.6.3. Coated opening rollers

Coated opening roller wire has been developed to extend the wire lifetime. The coatings, which are primarilydiamond particles in a nickel base, extend the lifetime by a factor of two to three times over the uncoatedwire. Coated wires are normally used for:

Viscose and viscose blends, synthetic fibres and blends, cotton with high trash content, coarse Count cotton yarns,

3.6.4. Lifetime of opening roller wire

The lifetime of opening roller wire depends upon: Material being spun, fibre type, staple length, fibre finish, trash content and the dust and sugar

content of cotton, production rate determined by yarn count and delivery speed, type of wire and coating. A significant factor in fibre finish is the amount of Titanium Dioxide used to produce dull or semi-

dull fibres. It is a very abrasive material and can rapidly destroy components. This can be a majorproblem when “unbranded” fibres are processed because there may be no control of the fibrefinish.

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3.6.4.1. Definition of lifetime

Wire lifetime has been exceeded when the wear of the opening rollers doubles the rate of ends down ascompared to the new opening roller.

The amount of material, which passes through a spinning position during the wire lifetime, is referred to as“M”.

By using the following charts, the amount of material “M”, passing through a position over a certain periodof time, can be seen. Similarly, the expected lifetime can be found for any count and delivery speed if thevalue “M” is known.

Lifetime of Opening Roller Wire

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3.7. Opening roller housing

The condition of the opening roller housing is very important to the consistency of fibre flow through thesystem. Defects, damage, wear or contamination cause yarn imperfections or ends down.Points affecting the function of the opening roller housing include:

The feed plate must be clean and not worn by either the fibre or feed roll. There should be no build up on the feed plate at the fibre feeding point. Cotton with “honey dew”

tends to form a brown build up at the fibre feeding point. This must be cleaned. The housing must not contact the opening roller head and interfere with the free rotation of the

roller. Damaged inserts or rough places cause fibres to tag. The tags eventually break free and cause

defect or end down.

3.7.1. Trash removal

A trash removal slot is provided to allow the separation of trash particles and fibres. The size of the trashremoval slot is selected to suit the amount of material passing through the system. As a guide the followingapplies:

16 mm slot for Nm 17 (Ne 10/1) and coarser,24 mm slot for Nm 17 (Ne 10/1) and finer.

For exceptional materials it is necessary to prevent material being removed through the trash slot. A pin is

available to fit into the housing, adjacent to the trash slot, to change the airflow and direct all material,including trash, into the rotor.The pins are primarily used for:

Flax and similar stiff fibres that tend to sling off the wire at the trash slot, blends that have a very high percentage of very short fibre – normally spun into coarse yarns, coarse yarns being spun from very trashy cotton, bleached cotton where there is no trash to be removed and the fibre tends to leave the opening

roller, in order to determine whether a machine should be equipped with pins in the housing, tests must

be run and the filter box material collected, measured and examined. Normally this step will havebeen done pre test before the machine is shipped.

3.8. Draft

Draft is a function of the yarn count and the weight of the sliver being fed.

Draft (V) = Nm yarn = Ne yarn or

Nm sliver Ne sliver

Draft (V) = Sliver weight (grains/ yard) xNe yarn

8.33

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3.8.1. Influence of draft

Higher drafts: With the R20 drafts up to 400 are possible for finer counts. The maximum sliver weight of 6.5 – 7.8

g/m or 90 – 110 grains/yard limit the draft range for coarse counts. More intensive opening of the sliver. Reduces yarn imperfections, improves Yarn evenness (CV%), permits heavier sliver weights to be fed which increases Drawframe productivity, enables one sliver weight to be used for most yarn counts, some materials cannot tolerate very high drafts and care should be taken to ensure that fibre

damage does not occur. Also, with high drafts the opening forces are increased which tend to wear out the opening roller

wire at an accelerated rate. Draft should not be excessive when spinning synthetic fibres.

3.9. Winding

Winding on the rotor-spinning machine is very important to the acceptability of the yarn in the downstreamprocesses. Optimization of the winding setup has to be done according to the end use. For weaving applications the package weight and density can be maximized for the required

diameter. Relatively hard packages are acceptable, but the yarn must be easy to unwind. For Dye packages the build of the package is very important to prevent uneven dyeing. The

density must be uniform throughout, from inside to outside and without hard edges. For knitting, the yarn must be uniformly waxed and the build must prevent excessive overthrows

that cause yarn tagging at the knitting machine.

3.9.1. Important winding settings and parameters

The following features directly affect the quality of the wound packages and should be carefullycontrolled to avoid package-related problems.

Cradle alignment – to be sure the package correctly sits on the winding drum, Yarn traverse width should be controlled or set to produce the needed package width. Yarn traverse displacement should be set to prevent the formation of hard or raised edges.

Angle of wind (helix angle) determines the package form and stability. The yarn winding tension has to be set to ensure that a working tension is maintained throughoutthe build of the package.

The “Anti-Patterning” has to be set to prevent yarns being wound excessively on top of previouswindings and creating ribbons.

Cradle pressure has to be controlled. The air pressure and air lines must be able to supply therequired air pressure to the winding zone throughout the package formation.

For knitting yarns, the waxing device has to set with the appropriate wax type and the correct rateof application.

The condition of the package-driving surface has to be able to drive the package at the requiredspeed to avoid variations of winding tensions form one position to another.

The yarn delivery roller has to be in good condition and should not have worn grooves that allow

yarn slippage.

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3.9.2. Cradle alignment

The cradle alignment is originally done before the machine is shipped. However, there are times when themachine has to be changed and re alignment has to be performed. The package must be driven equally ateach side. This is particularly critical for conical packages when using the differential drive. The tube mustsit so that both the nose and the base of the cone are evenly seated on the driving surfaces.

3.9.3. Yarn traverse

The yarn traverse mechanism can be set to wind packages of various widths.

With the mechanically set arrangement the stroke length can be 142 mm, 145mm and 148mm

mm. With the VSB box the overall stroke length can be varied from 125 mm to 155 mm. The package width is normally as wide as possible but for coarse yarns it should be limited so that

the package does not bulge and rub against the cradle.

The following guideline can be used:

3.9.3.1. Thread guide stroke

With standard box. 148 mm for yarns finer than Nm 40 (Ne 24/1).

145 mm for yarns Nm 15(Ne 9/1) to Nm 40 (Ne 24/1). 142 mm for yarns coarser than yarns Nm 15 (Ne 9/1). Stoke displacement adjustable between 0 and 5 mm.

3.9.3.2. Variable stroke gear box

Stroke length is adjustable between 125 and 155 mm Stroke displacement is adjustable between 0 and 30 mm.

3.9.4. Stroke displacement

The stroke displacement varies the position of thewindings so that there is not a concentration of yarn atthe edges. When the edge displacement is zero, thetraverse guide reverses at the same position at eachstroke. The edge is very hard and tends to build up to alarger diameter.With standard the winding system the stroke lengthremains constant and is displaced, over several strokes,to the left and then to the right. This creates a softeredge and a more uniform package density.

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Note: When the edge displacement is increased there is a tendency for the yarns to slip over the edge ofthe package and cause “overthrows or stitching. This can create problems in unwinding at the nextoperation.



Technology Handbook

3.9.5. Winding angle (Helix angle)

The winding angle is established by the speed of the yarn traverse guide and the winding drum.Increasing the winding angle has the following effect:

Winding angle Increase the package stability, (less bulging) tends to slightly reduce the package width, reduces the package density, reduces the package weight, increases the tension exerted upon the

yarn by the traverse guide, and may causeyarn breaks in the winding area.

Winding tension or winding speed mayneed to be reduced to compensate for the

change in forces exerted by the traverseguide.

Recommendations for winding angles: Cylindrical packages,

Maximum weight = 5 kg, Maximum diameter = 340 mm Winding angles = 32˚ (possibly 30˚, 34˚and 37˚)

Dye packages, Maximum diameter = 200 mm. Winding angles = 37˚ (possibly 40˚).

Conical packages Maximum diameter = 270 mm. Winding angles = 32 (possibly 34 or 37).

Measurement of the MeanWinding Tension

3.9.6. Winding tension

The winding tension draft has to be set to produce therequired package firmness. It depends upon:

The package application, weaving, dyeing or knitting, the elasticity of the fibres being spun, the winding angle, the spinning tension. the yarn should always be taut in the winding zone. the optimum winding tension can only be found by tests.

In some applications the tension draft has to be below1.0 to allow the yarn to relax between the spinning zoneand the winding drum.

The yarn tension curved bar is provided to produce an approximate constant yarn path length. This reduces thetension variation created by the yarn guide moving the yarn path from side to side. Even with this device there is

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always short-term tension fluctuations. Additionally, there is a tendency for the winding tension to be reduced asthe package builds.

When measuring the winding tension it is most useful to record the average value when there is 5 to 10 mm ofyarn wound onto the package.

3.9.7. Package cradle pressure

The cradle pressure is primarily dependent upon the pneumatic loading system. It is essential that there areno air leaks in the system, otherwise the pressure will vary. This leads to the formation of soft packages oflarger diameters.

Winding drum surfacesThe package is driven by the surface of the winding drum tires. As the surface wears or becomes slick, thedriving friction force is lower and the winding tension is reduced. This produces softer packages of largerdiameter.The loss of driving friction is critical with the differential drive for conical packages. When the tires losedriving friction, both have to be replaced. Oversized packages can create problems at the creel of the nextoperation.

3.9.8. Antipatterning

At certain locations within the package, the windings lay in patterns. This occurs when the traverse guidelays a yarn directly on top of a previous laid yarn. These patterns can interfere with the stability of thepackage and create problems during unwinding.The diameter of the patterning is dependent upon the winding angle and the stroke length. To minimize thepatterning effect, the winding angle is constantly varied slightly by the antipatterning device.

The drive of the yarn traverse gearbox is varied by +/- 2.5% or +/- 3.5% depending upon the shape of thecam used in the gearbox.

The most critical patterning occurs when the wound yarn makes one circumference of the package while the

traverse guide makes two strokes bringing the yarn back to the starting point. This is called the 1:1 patternand occurs around the maximum package diameter. Package diameters are usually limited to not reach the1:1 pattern.

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3.9.9. Recommended maximum package diameters

Winding angle (helix)148 mm stroke

30˚ 32˚ 34˚ 37˚ 40˚

Diameter (mm) of1:1 patterning

375 350 329 301 276

Maximum packagediameter

340 340 315 285 260

Winding angle (helix)142 mm stroke

30˚ 32˚ 34˚ 37˚ 40˚

Diameter (mm) of1:1 patterning

361 337 316 289 266

Maximum packagediameter

340 325 300 275 250

3.9.10. Yarn delivery top roller

The delivery top roller must be seated and pressured against the steel to securely pull the yarn out of therotor. The delivery rollers should prevent the yarn spinning tension from passing into the winding zone.In the event that slippage occurs at the delivery rollers, the tension in the yarn being wound will vary andcould be very high resulting in:

Some of the packages being very hard, variation in winding tension from package to package, the yarn will break frequently at the yarn traverse guide and piecing at package change will be difficult because the yarn will not be held by the delivery roller

during yarn transfer to the package.

The delivery top rollers must:

Have a smooth surface with no worn grooves when spinning fine yarn, when spinning coarse yarns, the rollers wear and very small grooves can be tolerated as long as

the yarn does not slip. Worn rollers should be buffed if possible or otherwise recovered. The top rollers must be aligned with the steel rollers to ensure that there is a controlling nip across

the width of the rollers.

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3.9.11. Winding speed

The rotor speed and the twist level establish the winding speed. For most yarns the winding speed is withinthe limits of the system. However, with coarse yarns and low twist yarns, the maximum delivery speed maylimit the productivity.

The guide rod speed depends upon the delivery speed and the winding angle. The rods have maximumspeeds and limit winding speeds. There are two types of rods:

made of synthetic material (CFK) and aluminium, made from chromium-plated steel.

The following table shows the maximum permissible delivery speeds when various winding angles are used.

Permitted delivery speed (m/min)Winding angle (helix)

Traverse guide rod(CFK) and aluminium

Traverse guide rodchromium plated steel

30˚ 220 150

32˚ 220 150

34˚ 220 140

37˚ 180 130

40˚ 170 120

3.10. Waxing

Wax is applied to knitting yarns to reduce yarn friction at the knitting needles. The yarn to metal friction canbe tested using several devices, but in all cases the average yarn friction is the most frequently used value.When the wax is applied between the delivery rollers and the winding drum, it is important that the yarnfriction should be as consistent as possible from package to package and throughout the package build.

The wax application is dependent upon the yarnwinding tension and the yarn path deflection overthe wax block. It is very important that the tensionbe uniform as the package builds.

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3.11. Piecing

The piecing process has to be optimized so that:

The piecing quality must not be an unacceptable yarn defect. The piecing strength must enable the yarn to withstand the requirements of the subsequent

processes, usually greater than 75 % of the yarn strength. The efficiency of first time piecing should be better than 80 %.

3.11.1. Piecing systems

On the R 20, two basic piecing systems are provided. 1) The SYNCRO TOP with fibre deflection and 2) the

“SYNCRO TOP 2” with “Feed / Withdrawal” synchronization.

With SYNCRO TOP, the piecing is made by feeding the sliver to the waste collection system until the damagedend has been removed,

dropping the yarn end into the rotor and then re-directing the opened fibre stream into the rotor as the yarn end is being removed.

With the SYNCRO TOP 2 system, the piecing is made by:

Feeding the damaged end of the sliver to the waste collection system, stopping the feed while the yarn end is placed into the yarn tube,

starting the sliver feed, the fibres going into the rotor, dropping the yarn end into the rotor and then withdrawing the yarn at a controlled speed corresponding to the rate of fibres being fed to the rotor.

SYNCRO TOP settings - To be added later SYNCRO TOP 2 settings - To be added later

3.12. Online quality monitoringSee operating instructions.

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4. Recommendations

4.1. Overview of preceding processes

Every operation from bale laydown to finisher drawing impacts the performance of rotor spinning:

4.1.1. Bale laydown

4.1.1.1. Cotton

The type of fibres arranged in the blowroom affect the preparatory process and the spinningperformance. If the cotton is contaminated with bark, polypropylene, waste fibres or excessive trashthe spinning performance will be compromised. Take care to check the quality of the cotton bales inthe laydown. Also check to see if the re workable waste is fed in a controlled manner.

4.1.1.2. Synthetic fibres

The finish on synthetic fibres is critical to the rotor spinning process. Try to obtain the labels from thebales that show the type and origin. If there are processing problems, the necessary facts about thefibre can be obtained from the fibre producer.

4.1.2. Blowroom

The blowroom machinery should run with a minimum standing time. Short bursts of very highmaterial flow rate followed by machine waiting times are undesirable.

Machines that are obviously in bad operating condition can cause problems of entangledfibres, high levels of neps, damaged fibres, and insufficient cleaning. Each of these caninterfere with the spinning process.

Waste feeding in the blowroom has to be consistent. When operators over feed the wastehopper or do not feed it at a regular rate, the percentage of waste fibres in the materialvaries. This results in the variation of short fibre content of the sliver and consequently

spinning performance and yarn quality varies. The cleaning machines should be functioning correctly. Care should be taken to be sure that

the waste removal system is effectively working. If the waste is allowed to accumulate it willbe sporadically sucked back into the cleaned fibre creating a very high concentration of trash.Some of this trash will be carried through to the spinning machine and cause spinning andquality problems.

Fibre transportation pipes can cause problems for the spinning machine.- Entangled fibres can be generated in the damaged pipes or in fibre pipes with bad

connections. This results in an increase in neps and slubs.- Long distances between machines can cause fibres to roll and become entangled.- Condensation can occur in pipes that extend between building and cause the fibres to

stick and choke in the system. Chokes result in matted and entangled fibres that can

be damaged in subsequent operations. Condensation tends to occur when the outsidetemperatures become low, i.e. overnight and during winter.

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4.1.3. Carding

The card can be a very effective machine in improving the quality of the fibres being processed. Whenthe machines are operating correctly the neps and trash are greatly reduced. The fibres in the sliverhave been individualized and a degree of fibre orientation is achieved.Cards that are not operating correctly can produce inferior quality sliver that can disturb the spinningprocess and cause yarn defects.

The feed from the chute to the card should be uniform across the matt and along the length. Ifthe matt is lumpy, the feed is not controlled and clumps of fibres can be pulled into the card.These clumps are then not carded correctly and sliver defects result.

Damaged card wire can create a bad carding condition and the sliver quality suffers. Neps, slubsand tags can be caused and create problems in spinning.

Incorrect settings of the carding components, licker-in, doffer and flats, produce bad qualitysliver. The nep removal and trash removal may be unacceptable.

The collecting and coiling of the sliver at the card can create tags slubs and clearer waste thatremain in the sliver and cause problems at spinning.

4.1.4. Drawing

The drawing process can cause problems when it is not performed correctly:

Coiling problems can cause the slivers to cling together and split. This produces a light yarnthat is either a quality cut or an end down. Another problem is that the coils may be foldedand the fold is pulled into the feeding funnel and chokes the feed.

Trash accumulated in the Drawframe can be pulled into the sliver and cause qualityproblems.

The settings of the Drawframes should be consistent across the spinning plant. OneDrawframe set incorrectly can produce high ends down at every spinning position thatreceives its sliver.

In the trouble shooting activities there are times when some cans of sliver are proven to bethe cause of ends down. If this can be clearly demonstrated, it is suggested that thetroublesome cans be put aside and concentrate on the machine spinning normal material.The Drawframe supplying the faulty sliver should be identified and corrected. It may be that

the problem is not at the Drawframe, in which case the card and card sliver should beexamined. It is possible that one card is creating a problem and that the material is beingchannelled through the drawing operations.

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4.1.4.1. Sliver quality

The following table lists suggested sliver characteristics needed for different yarn counts:

Yarn countup to

Trash % Sliver CV% Maximum fibre fineness

Nm Ne Drawn sliver Cotton micronaire dtex / denier12 7/1 < 0.30 < 4.0 < 6.0 < 6.6 / 6.020 12/1 < 0.20 < 3.8 < 6.0 < 3.3 / 3.0

27 16/1 < 0.15 < 3,5 < 6.0 < 3.3 / 3.034 20/1 < 0.12 < 3.5 < 6.0 < 2.2 / 2.0

40 24/1 < 0.10 < 3.5 < 5.2 < 1.7 / 1.550 30/1 < 0.07 < 3.2 < 4.2 < 1.3 / 1.2

60 35/1 < 0.05 < 3.0 < 3.8 < 1.3 / 1.270 41/1 < 0.03 < 3.0 < 3.6 < 1.1 / 1.0

CV% (1m) 0.8 – 1.0CV% (3m) 0.6 – 0.8Weight

Variation CV% (5m) 0.4 – 0.6

Spinning limits for rotor yarn,Carded cotton = 120 fibresMMF and blends = 110 fibres

4.1.4.2. Sliver evenness

The sliver evenness is very important and should be minimized whenever possible:

irregularities in the sliver cause yarn variations or ends down in spinning, finer yarns require a more even sliver, defects in the sliver are extended by the draft of the spinning machine and can become unacceptable long

thick or thin places, sliver in the cans should not be damaged, scuffed sliver causes the coils to cling to each other and then either choke at the feed zone or create a long

very thick yarn, loosely formed sliver tends to split and produce light yarn or ends down. Note: When ends down are caused by thick or thin sliver, the robot will normally fail to piece up until the

appropriate sliver weight is fed. This can greatly affect the piecing efficiency and subsequently the machineproductivity.

Sliver splicing should be avoided. Bad splicings will cause either an end down or a quality cut. It can be that

the robot will fail several times to piece up because of the excessive mass. It may be that the splicing chokesin the feeding zone and cannot be pieced up until after operator intervention.

The best yarn quality and piecing efficiency is obtained by manually feeding new sliver to the machine andallowing the robot to start spinning by making a piecing.

Felted or matted sliver due to abrasion in the can causes sliver tagging. The defective Drawframe with faultycan eccentricity should be identified and corrected so that there is clearance between the can and the slivercolumn.

Damaged cans and coilers can cause bad quality sliver, which create problems in spinning. Trash and clearer waste accumulated at the card or Drawframe and released into the sliver creates quality

problems and spinning ends down.

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4.2. Start up steps

At start up it important to perform the basic checks to be sure that the fibres and yarn count are consistent withthe components specified in the machine order and supplied with the machine.

4.2.1. Basic pre start up checks

The following is a list of points to be checked and recorded:

Yarn count and Twist requested by the customer.

Obtain sliver details before the machine is ready for start up, include - fibres, blend level, number ofdrawing processes, sliver weight, and sliver evenness - CV%. Try to obtain labels from man made fibrebales, try to obtain an overview of the preparation process from the blowroom through drawing.

Check to see if the requested yarns are included in the installation guidebook. If not find out if they wereproduced at ARIS as test before the components were specified and, in any case, obtain a set upverification.

Check the exhaust air the filter capacity should be able to receive the exhaust air without causing abackpressure.

Check machine components that are contacted by the fibre. If necessary, they should be cleaned with a milddetergent to remove protective coatings such as rust preventing oil.

Set the machine spinning controls to spin at average speeds for the yarn and components. Do not start upthe machine at the highest requested speed. The production optimization can be done when the machineand components have been run – in.

Set the quality control system according to the manual. For the initial check of the machine and the first fewkg of yarn produced as test yarn, set the quality monitor on the open side until the yarn sizing has beencompleted. However, as soon as practicable, the quality monitor should be re-set to help in correctingpositional problems.

Set the robot piecing program as outlined in the “Machine settings” or other guidelines. Some pointers aregiven in the operating and Installation manual. Aim at obtaining a reliable piecing action for the machine start

up and then optimize the settings when the machine is in production.

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4.3.1. Compressed air

The compressed air must be supplied at a minimum pressure of 600 kPa (6 bar).

The air consumption rate depends upon the length of the machine and the machine functions. Thefollowing chart shows typical air consumption rates:

High quality compressed air is necessary to run the AERObearing and for perfect rotor cleaning.Requirements on compressed air quality.The customer has to provide compressed air rotor cleaning of quality 3/4/3 by DIN ISO 8573-1:

Heavily solid particles, class 3; max. particle size = 5 µm; max. particle density = 5 mg/m3 Water content, class 4; max. pressure dew point = +3°C Total oil content (droplets, aerosols and steams), class 3; max. oil content = 1 mg/m3 (at 1 bar absolute

pressure, +20°C and relative steam pressure of 0.6 bar)


Each rotor-spinning machine produces an amount of exhaust air depending upon the length of themachine. It is VERY IMPORTANT that the filtration system is capable of handling the exhaust air anddoes not create a back pressure. There must be no positive air pressure in the duct beyond the fan.

The suction fan speed should be adjusted to provide:

Suction at the yarn tube - Minimum of 60 hPa (600 mm WS).Maximum of 85 hPa (850 mm WS).

Suction at the air duct of the robot rail system of –Minimum of 110 hPa (1100 mm WS).

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4.3.2.1. Waste removal

The filter waste collected in the machine must not be allowed to build up and reduce the suctioncapacity of the fans to below the required minimum values.

The waste removed from the opening roller housing and the spinbox can indicate that the machine isoperating correctly or not.If there is an excessive amount of fibre waste in the filter, it suggests that some of the rotors are settoo deep into the machine and fibre is flowing over the rotor rim.

4.3.3. Room conditioning

The temperature and relative humidity influence the rotor spinning process. Fibres respond tomoisture, if they are too dry they tend to be damaged more easily and yarn strength will be lost. Also,with synthetic fibres there will be a tendency for static to build up. On the other hand, if the moisture istoo high, the fibres tend to become sticky and contaminate the spinning components. The challenge isto find the optimal conditions for the fibres being spun and for the other operations being performed inthe vicinity of the spinning machines.

A general guideline is to use the water content of the air as a value to use to optimize variousconditions.

For most fibres, including cotton, viscose/rayon, polyester, and blends with these fibres, the air

water content should beapproximately 10 to 11g water / kg air.

100% acrylic - approximately 11 to 12g water / kg air. Sticky cotton (honey dew) 9 g water / kg air.

The following table shows the air water content depending upon the temperature and relativehumidity.

Relative humidity %

40 45 50 55 60 65Temp.C / F

g water / kg air (approximate)

22 / 71.6 8.5 9 10 11

23 / 73.4 9 10 10.7 11.524 / 75.2 8.5 9,5 10.5 11.5 1225 / 77.0 9 10 11 12

26 / 78.8 8.5 9.5 10.5 1227 / 80,6 9.25 10.5 11.5

28 / 82.4 10 11 1229 / 84.2 10.5 11.5

30 / 86.0 11 1231 / 87,8 12

This chart is based upon an atmospheric pressure of 760 mm. At higher elevations with lower

pressures the local moisture content should be obtained.

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5. Troubleshooting

The following should be helpful in analyzing situations and solving problems associated with spinningperformance.

5.1. Machine handling

Many small simple things can add up to a rotor spinning machine loosing production efficiency. Mostof the points are operator / technician related, but create the impression that “the machine is givingproblems”. Here are a few obvious ones:

Missing sliver cans and broken slivers. - Three events are more than 1% of the production. Red lights not attended to, or cancelled without correcting the cause. – Every three red lights

mean a loss of 1% of production. The larger problem is simply cancelling the red lightbecause the robot has to again go to the position and spend time trying to piece up. If therobot is programmed to make three attempts, it looses approximately 1.5 minutes of piecingtime.

Turning the position off without permission of the fixer and not noting the reason. Sometimespositions are left off for days without being given attention. This reduces the machineefficiency.

Robot settings being performed by all fixers to make the robot effective. Once the robotsetting has been established, it should not be changed in order to piece up a spinning

position. If the robot consistently fails to piece up at a position, it is because the position is inneed of attention – not the robot.

Package removal can greatly interfere with the machine efficiency if the package handlers donot remove all the packages in an effective manner. When the machine package doffing isstarted, the robot cannot doff full packages at the spinning positions. These positions aremomentarily out of production. If for any reason the removal is delayed, several full packagesare accumulated and production is lost.

Topping cans with the last few layers of the previous cans leads to production loss. When theslivers are spliced, the mass is usually not acceptable to the yarn quality monitor and thisleads to a quality stop. Unfortunately, part of the defective splicing can be in the feeding areaand causes a robot piecing failure. Sometimes the sliver jams at the feed and may not bedetected and result in several missed piecing attempts. The “Procedure to re start red lights”

(5.3) should be followed.

5.2. Checking the ends down level

It is frequently necessary to manually check the number and cause of ends down on a part of a machine orthe whole machine. Sometimes different components are being compared as part of an optimizationprocedure. The following is a general recommendation.

Prepare a checklist that contains all pertinent causes of ends down. When the machine is running and ends are known to have come down, walk in front of the

robot and analyze the end down before the robot is allowed to piece up. Record the position number, time and type of end down.

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By recording the running time, number of positions being evaluated and the number of endsdown during the evaluation period, the absolute rate of ends down can be calculated. Divide

the number of ends down x 1000 by the number of rotor hours evaluated.

Ends down / 1000 rotor hours = Number of ends down x 1000Number of positions x Running time (hr)

To obtain reliable machine ends down data it is suggested that the full machine should bechecked for a period of two hours to give data for more than 500 rotor hours.

5.2.1. End down analysis

Check the yarn end on the package and the remains in the rotor at each end down.

PROBLEM /Abbreviation

APPEARANCEProbable cause of end down

Fibre accumulations /“FA”

Yarn end has entwined entangled fibresCause:Possibly damaged opening roller wire, or fibre accumulations in the openingroller housing or entangled sliver.

Fibre accumulationsin the rotor/“FAR”

Yarn end has a clean break with yarn remaining inside the rotor cup - fibreaccumulation clinging to the piece of yarn.Cause: Possibly damaged opening roller wire, or fibre accumulations in the opening

roller housing or entangled sliver.Tapered /“Ta”

Yarn end tapers off – thin end.Cause:Insufficient spinning stability, insufficient twist insertion to the rotor groove.Recommendation: Increase real twist, or increase false twist by the use of amore aggressive nozzle or by increasing the rotor speed.

Foreign fibre /“FF”

Foreign fibre embedded in the yarn end or in the yarn portion left in the rotorgroove.Cause:In most cases, it is polypropylene from the bale wrapping material, but also itcan be coarse vegetable matter such as bark from the cotton plant or weedsgrowing with the cotton. Where the cotton is contaminated fabric, unopenedthreads can cause an end down. Additionally a release of part of a lap on the opening roller may appear asforeign fibres.

Quality stop /“Q”

A quality stop always produces a long tapered yarn end by stopping the feedwhen a defect is recognized.Cause: The machine display indicates the reason for the quality cut. If it isbecause of a slub, thick place or foreign fibre, the defect can usually be foundby winding off 2 to 5 meters of yarn.

Yarn piece in the rotor /“Y”

Yarn end is a clean break. A piece of yarn remains in the rotor cup.Recommendation: The spinning tension exceeded the yarn strength.Reduce the spinning tension by using a less aggressive nozzle and, if

necessary, lowering the rotor speed.

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Yarn end tapering off /“Yt”

Yarn end -long tapering off and leaves only fibre in the rotor cup.Recommendation: Check to see if it is a quality cut. If not, check the content

of the filter box for excessive fibre waste.Check the “rotor depth”. If the rotor is set too deep into the machine,

some of the fibre tends to flow over the rotor rim and starve the spinningprocess.

5.2.2. Typical ends down list

Record the position number and type of stops.

… Position type of end downl l ll 1st hour l 2nd hour l 3rd hourl l l

12 l Y, Y, FAR, l Y, S l28 l FA, FA l FA l

116 l FF l l175 l Yt, Yt l Yt l75 l S, S l S l9 l ta l l

Additionally, the data can be compiled to show an overall performance as follows:

Ends down level check

Y ///FAR /S ////FA ///FF /Yt ///Ta /

If the above data was taken from both sides of a machine:

The overall spinning condition seems to be good, positions 12, 28 and 175 need attention and the sliver at position 75 should be examined for contamination. ( S = Sliver related)

5.3. Procedures to re-start positions with red lights

When the robot fails to piece up an end, it leaves the position with a “red light”. Many operators do nothingbut cancel the light to allow the robot to again attempt to piece the end. This is a very bad practice andshould forbidden. When the robot fails to piece up, it should be considered that something is not in order

with the spinning/winding unit.

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A suggested approach for operators to identify and correct faults is given in the following chart.

5.3.1. RIETER R20 “OPERATOR REDLIGHT CHECKLIST”

(Steps to eliminate source of robot failure)

Pos.#

Description

1 If robot failed at piecing on package – is sliver available?2 If robot failed at piecing on empty tube – is empty tube available? Is package belt empty?

3 Any lights on at spinbox? – Check signals

4 Check yarn package for tangles – place yarn end towards the left end of the package

5 Are there any lap-ups on the winding drum? – Do not try to remove!6 Is the wax disc O. K. (smooth, no cuts)? – Shave it with provided tool

7 Wipe out yarn monitor and yarn clearer – use brush or soft cloth8 Does the yarn clearer indicate any quality alarm – if so, correct

9 Are there any lap-ups on the delivery shaft / top roller?10 Is the sliver O. K. (check for split sliver and kinks and chokes at the condenser)?

11 OPEN THE SPINBOX – make sure rotor has stopped completely!12 Is there any tangled yarn at the nozzle?

13 Does the opening roller turn freely?14 Is the spring at the feed plate seated properly?15 Check the feed roll for lap-ups and cleanliness

16 Clean faceplate and nozzle with sliver or rag17 Check the yarn tube for proper fitting and clean with pipe cleaner18 Wipe out rotor – make sure rotor has stopped completely!19 CLOSE THE SPINBOX

20 Press rotor control lever down until it latches in – rotor starts21 Feed sliver for approximately 1 sec. by pressing the yellow pushbutton to see if the sliver is it

pulled in correctly?If the sliver is not pulled in, carefully remove the sliver end by twisting the sliver and pulling it outof the feeding system. Remove any faulty sliver and then re-feed the sliver end, being sure thatthe sliver is taken in.

22 OPEN THE SPINBOX ONE MORE TIME23 Check for fibre ring in the rotor – is it visible? If not, repeat #20 through #23

24 If fibres still don’t feed into rotor, check for blocked opening roller25 Remove any fibre from the rotor cup and wipe out the rotor again.26 CLOSE THE SPINBOX

27 Press rotor control lever down again until it latches in – rotor starts28 Make sure all signal light at the yarn monitor and the clearer are off

29 Let the robot try to piece up this spinbox again30 If the failure reoccurs, flag spinbox, take note of the spinbox #, and call technician

Shaded lines indicate “first priority tasks”, which should be standard procedure in the Operator’sattempt to troubleshoot spinbox related problems.

The other procedures listed (white lines) are additional steps, which can be taken if the usualcleaning procedure does not get the spinbox to run again.

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5.4. Fly and dust accumulation at the feeding zone

Where the rotating opening roller contacts the sliver being fed, a high-pressure zone is created. Thistends to “blow out” dust and fine fibre. Counteracting this build up of air pressure is the suctionapplied to the opening roller housing from the spinbox. When the suction (under pressure) issufficient, it overcomes the pressure build up and prevents blow out of fly at the feeding zone.If the spinbox and the opening roller housing are not correctly sealed and false air is sucked into thesystem, the air balance is disturbed and blow out will occur.

The following places are potential points of leakage:

Feed roll set too far away from the opening roller housing. Feed plate not seated correctly. Feed plate contaminated and closing the gap between the feed plate and the opening

roller. The opening roller cover plate incorrectly seated. Damaged or worn seals at the outlet of the fibre channel in the opening roller housing. Faceplate incorrectly positioned or aligned and leaving a clearance through which false

air can enter. The seal of the Fibre Deflection opening must not allow air leakage. The spinbox door seal must be correctly fitting against the rotor housing. The spinbox door must be firmly held against the rotor housing. The rotor shaft seal in the rotor housing must be in good condition. The suction system connected to the rotor housing must be in order. The suction duct along the length of the machine must be connected and sealed

correctly. The suction fan should be correct and running at the appropriate speed for the altitude. There should be no backpressure at the suction fan.

The following points influence the fly at the feeding zone:

Higher opening roller speeds increase fly, spinning coarser counts increases fly. Spinning fibre with high waste or short fibre content increases fly. Double wound opening rollers increase fly.

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5.5. Application of Barco yarn clearer with polyester yarns

5.5.1. Facts we need to know about Barco yarn clearing: 11 Points

For the operation of the Barco yarn clearing system some important points are to be considered:

1. The Barco yarn clearing is an optical system, which determines the yarn diameter in mm. The measuringslot has a width of 2,5mm.

2. The invisible infrared beam, throws a sharp silhouette of the yarn on the sensor. Not only the yarn bodyshades the sensor, but the entire yarn covering (hairiness). Also dust particles, which accumulate in themeasuring slot produce shadows and falsify the yarn signal, which then pretends as thick yarn.

3. The resolution of this system is 0,01mm. Totally 256 steps (2 to the power of 8 bits) are available for gradualmeasuring of the yarn diameter, i.e. 1 step amounts to 0.01mm, the largest measurable thick place istherefore 2,56mm.

4. The resolution of 0,01mm is problematic. For example, a yarn of 19 tex exhibits a medium yarn diameter of0,20 mm, i.e. for the monitoring of this yarn a number of 20 measuring steps of 0,01mm are available. Thisresults in a highest possible measuring accuracy of 5%. Adjustments for a yarn in the range of 20 tex, haveto take place in 5%-Steps, since the system can not adjustment for finer increments.

Yarn 19 tex

20 Ste s = 0.2 mm

total 256 steps

each step 0.01 mm

To the example above: A yarn of 19 tex has a diameter of exactly 0,20mm. For the measurement of this yarn20 steps of 0.01mm are available. With an absolute measuring accuracy of +/- 1 step, a resulting field oftolerance of +/- 5% = 0,19mm to 0,21mm, or of 16.7 tex up to 20,4 tex, and/or 19 tex -12% /+7,4% (19 tex =100%).

5. The reduced measuring accuracy with finer yarns affects the function of the selective V-channel and C-channel. The C-channel is not to be used for yarns of 20 tex and finer.

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6. With the matrix SLT (short thin places, thick places up to 1m) the influence of the resolution is not assignificant. The adjustments are much coarser in this range.

7. It is very important to keep "tex" and "diameter" for each yarn in mind. The relationship between tex anddiameter is a nonlinear function. To determination of the yarn diameter, the so called Barco formula exists:

Barco – Formula:5.1

tex057.0mmind =

0.057 is a constant1.5 is the specific weight in g/cm3 for Cotton

Theoretically, the specific weight of the yarn has to be considered with conversions:Density in g/cm3: PES 1.4

PP 0.9Example: yarn Ne 30 tex = 591 / 30 = 20

5.1

20057.0mmind = = 0.21 mm

8. Various diameter information must be distinguished:

• Mean yarn value of spinning position: Is developed in stages during piecing, followed by data-storing

after 100m yarn, with last update after 1000m, thereafter final data-storing to the end of the batch. Thefollowing clearer functions depend on the mean yarn value of the spinning position:Matrix SLT, V-channel long thick- thin places, Mo-channel Moire, PC-channel Pearl Chain.

• Reference of Spinning position: corresponds to the saved mean yarn value of the spinning position, untilthe end of the batch.

• Act. value of the spinning position: actual mean yarn value of the spinning position for the last 100myarn.

• Mean yarn value of the machine: the mean yarn values at least 20 spinning positions are necessary,whereby each spinning position has to produce at least 1000m yarn without a break. The mean yarn valueof the machine is ready after the 21st spinning position. The following functions depend on the mean yarnvalue of the machine: C-channel very long yarn errors, CV %, imperfections, Ref. mean value,Spectrogram.

• Reference of the machine: corresponds to the mean yarn value of the machine, which is stored to the endof the batch.

• Act.value of the machine: actual mean yarn value of the machine of the last 100m of each active spinningposition.

• Ref. mean value: Mean yarn value of the machine with an adjustable tolerance field. After starting the 21st spinning position, the first 100m yarn are compared to the machine mean value. The piecing of eachadditional spinning position is monitored after starting a new batch assortment.

• Yarn mean value of the dynamic dust monitoring: in periodic, adjustable increments, the systemcontinually determines the mean value over 100m, compares it with the stored yarn mean value of thespinning position and carries out corrections in periodic interval.

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9. The spinning start is initiated with the selection "new batch" in the menu screen batch. All data of theprevious batch are deleted.

What happens at spinning start?

Saving of SpS-meanvalue till end of batch

Start of monitoring:dynamic dustcompensation

Compare SpS-mean value to themachine mean value after the 21st

spinning position

Robot dropsthe yarn

Start of evaluation

Idle time

Calibration to 0 mm

Dust signal

Start of monitoring:- C - channel- CV %- Spectrogram- Imperfections- Ref. mean value- Piecing

Start of clearing:- SLT – channel- V – channel- Moire - channel- PC - channel

0 2m 4m 6m 8m 10m 20m 100m 1000m Yarn len th

Yarn-Diameter

0 mm

Explanation:

- Dust signal: The sensor might be somewhat dusty from previous operations. The dust covers the sensor

partially and produces thereby an erroneous signal, which mimics a yarn diameter.- Calibrating to 0mm: A short time before the robot inserts the new yarn, the clearer system adjusts the dust

signal to 0mm yarn diameter.- Robot releases yarn: The robot has pieced-up the new yarn and guides it into the measuring slot of the

sensor. As soon as the sensor captures the yarn completely, the yarn signal is proportional to the yarndiameter. The smallest measured value is 0.01mm, the largest detectable diameter is 2,56mm.

- Idle time: For the short time of inserting the yarn up to the beginning of the evaluation (0m) no monitoringof the yarn signal takes place.

- Start of the evaluation 0m: After 2m yarn, the yarn mean value is formed. This mean value is stored. Upto 10m the system updates the yarn mean value every 2m, from 10m to 100m the actualization takes placein steps of 10m yarn. Only the last updated mean value over 1000m yarn is reported to the machine meanvalue.

-Start yarn clearing 2m: From here, the clearing channels thick places, thin places etc. including the foreignmatter clearing are started, however without the monitoring of the yarn quality.

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- Start monitoring of the yarn quality 100m: The monitoring of the yarn quality C-channel, CV% etc. startshere. Now the complete yarn clearing and quality control functions are activated for every spinning position.

-Storing the spinning position mean value 1000m: After 1000m of continuous yarn run the spinningposition mean value is stored to the end of batch.

- Comparison of the yarn mean value to the machine mean value 1000m: This monitoring is availableafter the 21st spinning position has been started (see phase 2). The first 20 spinning positions must form themachine mean value and therefore are not examinable. At each spinning position, the last update of theyarn mean value for the corresponding spinning position takes place after 1000m yarn, which remainsunchanged to the end of the batch. In addition, the system uses the yarn mean value over 1000m of eachnewly started spinning position as input for the machine mean value.

- Start dynamic spinning position monitoring 1000m: The dynamic spinning position monitoring worksfrom here. The first compensation takes place after the completion of the adjustable "dust length" (normally

2000m), i.e. totally 3000m after the spinning start.

Phase 2:After the 21st spinning position, the system compares each spinning position - mean value of a newly

started spinning position with the machine mean value.

Falls the freshly formed yarn mean value over 100m yarn of a newly started spinning position, above or below theselected tolerance field, this spinning position is stopped. This applies from the 21st spinning position.

10. The system has 2 kinds of dust compensations: static dust compensation and dynamic dust compensation:

• The static dust compensation (see chapter 5.5.2 for function) is active when measuring slot is without yarn. Itcompensates for the remaining dust in the empty measuring slot. When the dust amount exceeds a definedlimit (max. dust) the spinning position is blocked (LED green and red are lit) the operator must clean themeasuring slot. After cleaning, the LEDs turn off as soon as the lower limit (dust-warning) is reached.

• While the yarn is running, the dynamic dust compensation (see chapters 5.5.2.1. & 2 for function) comparesin periodic intervals the act.mean value of the spinning position to the stored mean value of the spinningposition, which remains until the end of the batch. If the act.mean value is higher than the mean value of thespinning position, a correction of minus 0.01mm takes place while the yarn is running. If the actual meanvalue is lower than the mean value of the spinning position, a correction of plus 0.01mm takes place. Theinterval between corrections is selectable with the so called "dust length" (e.g. 2000m). When the

contamination exceeds a defined limit (max. dust) a yarn cut takes place, the spinning position is blocked(LED green and red are lit) and the operator must clean the measuring slot.

11. Option foreign matter recognition FF-ABS: If this option is available and for technological reasons one wouldlike to switch it off (for example with PES), it is not sufficient to simply set this function in menu "Profile,Settings, Foreign Fibre" to zero. This leads to disturbances. It is necessary to switch off the option as a wholein the menu of “Profile, Settings, Special” (only visible with Login).

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5.5.2. Function of static dust monitoring

Manual cleaningLower dust limit

Dust warning25 %

Yarn length0 mm

Upper dust limit

Yarn-signal without dust

Yarn drop

Yarn-signal with dust

Low dust LED red and greenoff. The remaining dust signalis automatically compensated

to 0 mm

Disturbance by dustLED Red onLED green on

Yarn break

Yarn-diameter

Max. dust0.50 mm

25%

100%

Large contamination • Taken place after each yarn break or clearer cut.

• The dust in the measuring slot produces an interference level without yarn.

• If this interference level is higher then the adjustable limit max. dust, the spinning position is blocked, therobot does no longer piece-up.

• LED green and red on the measuring head are lit.

• The operator must clean the measuring slot.

• By this cleaning the interference level sinks.

• As soon as the interference level drops below the adjustable limit dust warning 25%, the two LEDs turn off.

• The system compensates the remaining interference level on 0mm.

• The spinning position is automatically released, the robot is piecing again.

Small contamination

• If the interference level after a yarn break or yarn cut remains below the adjustable limit max. dust, thespinning position is not blocked.

• The LEDs are not lit.

• The system compensates the entire interference level on 0mm.

• The robot is piecing-up.

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5.5.2.1. Function of dynamic dust monitoring: Small contamination

Yarn + dust – 0.01mm Yarn + dust

Range of small contamination

Correction-0.01 mm

Check: deviation toS S-mean value

0 mm- 100%

Next correction after 2000 m

Act. SpS-mean value100 m arn len th

SpS-mean valuez.B. 20 tex

= 0.20mm = 0 %

100 m

1900 m0 m 2000 m

Yarn length

Yarn diameter

Limit max. dusti.e. 0.50 mm

Dust length

• The act.SpS-mean value is lower then the limit max.dust. • At the end of the adjustable "dust length" (here 2000m), a correction act.SpS-mean value takes place. • Correction: If the act.SpS-mean value is larger than the mean value of the spinning position, with yarn

running, a correction act.SpS-mean value of minus 0.01mm takes place. If the act.SpS-mean value is lowerthen the mean value of the spinning position, a correction act.mean value of plus 0.01mm takes place.

• The size of the corrective-step, of 0.01mm is not adjustable. • By reducing the dust length, the number of corrective-steps can be increased. •

The bearing of the correction depends on the yarn number: A yarn of 100 tex has a diameter of 0.47mm. The correction of 0.01mm corresponds to 2% of the yarndiameter. A yarn of 20 tex has a diameter of 0.20mm. The correction of 0.01mm corresponds to 5% of the yarndiameter.

• This correction mechanism is always in activated, it can not be switched off. • After a new batch is started, the dynamic dust compensation begins with 1000m yarn. The first correction

follows after the dust length (here 2000m), i.e. the first correction is executed after 3000m yarn subsequentto the start of a new batch.

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5.5.2.2. Function of dynamic dust monitoring: Large contamination

Yarn length

Range of smallcontamination

Yarn signalwithout dust

Manualcleaning

LED red offLED reen off

Dust signalLED red onLED green on

Dust warning25 %

Cut

Limit max.dust

Check: deviation fromSpS-mean value

0 mm = - 100%

Dust length

Yarn + dustAct. SpS-mean value 100 myarn length here above limit

max. dust

SpS-mean valuez.B. 100 tex

= 0.47mm = 0 %

100 m

1900 m0 m 2000 m

Yarn diameter

• Because of contamination, the act.SpS-mean value is higher than the adjustable limit value max.dust.

•

After the dust length (here 2000m) is reached, the yarn is cut.

•

The spinning position is blocked.

• The green and red LEDs on the MK are lit.

•

The robot no longer pieces-up.

• The measuring slot must be cleaned manually until the two LEDs turn off.

•

After cleaning, the signal must be below the dust-warning 25%.

• The spinning position is automatically released, the robot is piecing-up.

Example: Dust warning 25%Max. dust : 0.5mmWhere is the lower dust limit value dust-warning in mm?0.5mm – 25% = 0.38mm

The higher the percentage of the dust warning is selected, the closer to 0mm will this limit be, i.e. the operatormust clean the measuring slot more thoroughly. This applies also to the static contamination.

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5.5.3. With PES, three completely different problems must be held apart:

• Problem No. 1PES + Rotor = DustVarious factors influence the dust formation (PES type, type of rotor etc.). Increasing dust in the rotor,changes the yarn characteristics and finally leads to a premature, natural yarn break.

• Problem No. 2Dust + optical yarn clearing = function of the yarn clearing disturbed.The optical yarn clearing cannot differentiate between dust and yarn diameter. Each dust particle shadesthe sensor in addition to the yarn. Dust in the measuring slot pretends a larger yarn diameter. In the courseof operation, a clean measuring slot inevitably and increasingly gathers dust (= thick place) in addition, dustcan suddenly fall out (= thin place).

• Problem No. 3Yarn Ne30 + Barco clearing = problems with the settings.The Barco yarn clearing has a resolution of 0.01mm, the yarn Ne30 = 20 tex a diameter of 0,2 mm. For themonitoring of this yarn 20 steps of 0,01 mm are available. This results in a highest possible measuringaccuracy of 5%. Settings for a yarn of the count range Ne 30 have to take place in 5%-steps, the systemcannot capture smaller increments. See Chapter 5.5.1 point 4.

Example:Machine: R40V3 with 1 section, Pilot machineRotor: 37 XT BD with 90k/minOpening roll: OS21DN with 8.5k/min

Twiststop: whiteNozzle Mima 1Yarn clearing: Barco Profile with Option FF-ABSGarn: Ne 30Material: PES 1.2/1.4 denFibre length: 38/40mmProducer: Hazira Patalganga

Problem: MK dusty, the optical yarn clearing works unreliably.

Observation: Settings:

- Rotor accumulates dust, a yarn break results- Piece-up by Robot- Vminus Stops, shortly after piecing +/-18%, 3m- Correction: no improvement +/-18%, 9m - Correction: results in improvement +/-30%, 9m

Is it possible to improve the function of the yarn clearing by PES processing with certain systemsettings?

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5.5.4. Why does the Vminus-channel cut after a yarn break?

Vm el

Limit Vminus-channel

Cut

Break

Compensation

Act. SpS-mean valuebelow the limit

inus-chann

Dust falls out throughyarn drop

Limit Vplus-channel

Yarn signal +dust

Break

0 mm = - 100%

Act. SpS-mean valuelast 100 m yarn length

SpS-mean value20 tex

= 0.2mm = 0%

100 m

0 m

Yarn length

Yarn diameter mm

Explanation:

• Yarn signal + dustBecause of increasing contamination of the measuring slot, the yarn signal rises.

• SpS-mean valueThis mean value is formed by the yarn clearing system, from the first 100m yarn of each spinning position,with the start of a new batch. It is updated once more after 1000m and remains stored to the end of batch.The SpS-mean value is a static mean value.

• Act SpS-mean value of the last 100m yarn lengthThis mean value is constantly formed and displayed from the last 100m yarn. The actual mean value is adynamic mean value.

• Limits Vminus channel, Vplus channelIf the yarn signal + dust deviates above or below these limits, a yarn cut takes place.

• BreakThe accumulation of dust in the rotor weakens the yarn. A natural yarn break follows.

• Compensation After the yarn break, the dust remains in the measuring slot. Briefly before the robot pieces-up, the systemautomatically compensates this dust (disturbance signal) to 0mm.

• Dust falls out through the yarn drop The robot drops the yarn into the measuring slot. The yarn movement causes the dust to totally or partly fallout of the measuring slot. Because of the previous dust compensation, the -100% point falls below the 0mm-value.

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• Act.SpS-mean value below the limit Vminus channelThe act.mean value of the newly inserted yarn does not reach the limit of the Vminus channel because of the

dust compensation: a yarn cut follows.

Note: The quantity of dust in the measuring slot can reach enormous dimensions, which even exceedthe yarn diameter of fine yarns.

5.5.4.2. Measurement to prevent V-cuts

• Open-up the Vminus channel resp. switch off the Vminus channel.Reduces the probability that after a yarn break, the Vminus channel triggers a yarn cut. Disadvantage: the

monitoring of the yarn is reduced, besides the dust-filled rotor produces defective yarn. • Activate the dynamic dust monitoring for large contamination.

With increasing contamination, the yarn clearing system triggers a yarn cut. Set the upper stop limit max.dustin such a way, that the spinning position is blocked and the LEDs of the measuring head, signal for manualcleaning of the measuring slot.

Upper limitMax. dust

Test distance

Range of the small contamination.The corrections of 0.01mm

take lace here

Yarn signalwithout dust

Manualcleaning

LED red offLED green offCleaning O.K.

Dust signalLED red onLED reen on

Lower limitdust warning 25%

Cut

0 mm =- 100%

Dust length

Yarn signal with dustAct. SpS-mean value above

100m yarn length. Here already

SpS-mean value20 tex

= 0.2mm = 0%

100 m

0 m

Yarn length

Yarn diameter

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5.5.5. How does the dynamic dust monitoring function?

1. Monitoring of the distance between SpS-mean value (reference) and act.SpS-mean value.

2. If this figure is still within the field SpS-mean value and upper limit max.dust, a correction act.SpS-meanvalue of 0.01mm in direction SpS-mean value results at the end of the dust length. The yarn keeps running.

3. If this figure is above the upper limit max.dust, a yarn cut results at the end of the dust length. LED greenand red are lit, the robot does no longer piece-up.

4. Now the operator must clean the measuring slot until the dust signal falls below the limit dust-warning 25%.The LED turns off. The system releases the spinning position automatically, the robot is piecing again.

5.5.5.1. Explanation to dynamic dust monitoring:

• SpS-mean valueThe yarn clearing system forms this mean value for each spinning position from the first 100m yarn afterstarting a new batch. It is updated after 1000m once more and remains thereafter stored to the end of batch.The SpS-mean value is a static mean value.

• Act.SpS-mean of the last 100m yarn lengthThis mean value is formed continuously over the last 100m yarn. The act.SpS-mean value is a dynamic

mean value. If the act.SpS-mean value exceeds the upper limit, a yarn cut takes place after completing thedust length.

• Dust lengthThe dust length is programmable. Always after completing the set dust length with yarn running, either acorrection act.SpS-mean value of 0.01mm or a yarn cut follows:- Correction: the distance between SpS-mean value and act.SpS-mean value is lower then the upper limitmax.dust. The shorter the selected dust length, the more effective the correction.- Yarn cut: the distance between SpS-mean value and act.SpS-mean value crossed the upper limitmax.dust.

• Upper limit max.dust

The upper limit max.dust is programmable. If the yarn signal inclusive dust crosses this upper limit max.dust,the yarn is cut after the completion of the dust length. The LED the green and red are lit, the spinningposition is blocked.

• Lower limit dust warning 25%The lower limit dust-warning 25% is programmable. Thus the manual cleaning after a yarn cut can beinfluenced. The operator must clean the measuring slot, until the LEDs turn off. As soon as the LEDs turnedoff, the spinning position is automatically released. The lower the bottom limit of the dust-warning is selected,the more thoroughly the measuring slot must be cleaned.

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Example: Dust warning 25%Max. dust : 0.5mm

Where is the lower limit of the dust-warning in mm?

0.5mm – 25% = 0.38mm

- With the above example default values are used.- Consider this: Yarn Ne 30 = 20 tex = 0.2mm.- The upper limit 0.5mm corresponds to the 2.5 fold yarn diameter.- The lower limit 0.38mm corresponds to practically doubled the yarn diameters.

Important: The upper and lower limits must be adjusted according to the yarn and dust problems.

Large disadvantage: with the start a new batch, the dynamic dust compensation of a spinning position isready only after 1000m of continuous yarn are produced.

This means that each SpS must first produce 1000m yarn without interruption, after a new batch is started. Afterthe 1000m, the dynamic dust compensation switches itself on. The correction act.SpS-mean value can take placefor the first time, after completing the set dust length (default value 2000m), i.e. from the spinning-start to the firstcorrection 1000m + 2000m = 3000m yarn have to be produced.

5.5.5.2. How can we improve this disadvantage?

1. This significant length after spinning-start can be shortened by reducing the dust length drastically, forexample to 500m. Now the first correction occurs already with 1500m yarn length. Subsequently, every500m a correction step of 0.01mm takes place toward the SpS-mean value. If the act.SpS-mean value fallsbelow the SpS-mean value, e.g. because a dust particle fell out of the measuring slot, the direction of theautomatic correction changes upward, always toward the SpS-mean value.

2. Important point:

The sum of the correction steps must be larger than the developing dust in the measuring slot. This is

adjustable with the dust length.

3. The upper dust limit "max.dust" is to be reduced. As a consequence, a yarn cut can take place withexcessive dust.

4. The lower dust limit "dust-warn." is to be increased. With this measure the lower dust limit is brought downi.e. intensified. As a consequence, after a yarn cut (green and red LEDs are lit) the measuring slot must becleaned thoroughly. Releasing takes place via the cleaning of the measuring slot.

5. These measures bear influence on the entire operation: if the dust level in an empty measuring slot exceedsthe upper limit "max. dust", the spinning position is blocked indicated by the green and red LEDs, even with

a normal SLT cut.

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5.5.5.3. Assessment of these measures: Does the dust management function?See photos next page.

1. The assessment takes place in the menu SpS-classification. Here one can read:- Reference = SpS-mean value: does it correspond with the computation (Barco formula)?- Actual value = act.SpS-mean value: does it correspond with the reference? If the correction mechanism

works normally, the deviation may only amount to a few 0.01mm.- Dust: the display "0" is suspicious, that somewhat is not correct. The dust can easily amount to 0.15mm and

more.- Is the CV% about normal? High CVs points to an insufficient act.SpS-mean value, for example, caused by

dust falling out of the measuring slot.

2. After beginning a new batch, the operator must carefully monitor at least the first 20 SpS.

5.5.6. Practical examples

PES Ne 30, 20 tex, 0.2mm2 Tests Both tests were accomplished simultaneously on 2 different spinning positions.

Test No. 1With 1 Drawframe passage only a small amount of dust develops in the rotor:

- Spinning trial mostly normal, only few Vminus-cuts- Thin places Class "-20%/160mm" and "-20%/320mm" no thin places- CV% normal- Dust 0.11mm (50% of yarn diameter !)- Act.SpS-mean value similar SpS-mean value (Reference)

Menu spinning position classification:

No thin places

S S-mean value

CV% normal

Dust 0.11mm

Act.SpS-mean value~S S-mean value

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The above SpS-classification shows:

• SpS-mean value is rather somewhat lower than computed with the Barco formula. This is only possible,when no dust developed during the spinning start-up.

• Act.SpS-mean value corresponds basically to the SpS-mean value and indicates with this fact, that the yarnclearing system captures the yarn count correctly.

• Dust 0.11mm indicates that the measuring slot, with a build of 0.11mm, already accumulated significantdust. The act.SpS-mean value corresponds however to the SpS-mean value. This indicates that the amountof dust 0.11mm, has been completely adjusted by the dynamic dust compensations.

• CV% is an optical CV and correspond to this yarn.

• Thin places are not registered in the two classes "- 20% /160mm" and "- 20% /320mm".

We cannot consider the machine mean values (named "M"), since other spinning position trials took place at the

same time. In addition, the factor "dust" for the machine averaging is always comprised of the dust component ofall SpS, this machine has only 20 positions. The system captures automatically a 0mm value for SpS, which arenot in operation.

Test No. 2With 2 Drawframe passages lots of dust develops in the rotor:

- Spinning trial problematic, many Vminus cuts- Thin places Class "-20%/160mm" and "-20%/320mm" high number- CV% high

- Dust no indication, undefined- Act.SpS-mean value large difference to SpS-mean value (Reference)

Spinning position classification:

Thin placeshi h amount

CV% high

Dust undefined

Act.SpS-meanvalue too small

SpS-mean valuehi h

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Technology Handbook

The above SpS-classification shows:

• SpS-mean value is 0.04mm higher than with 1st trial. Probably some dust developed already during thespinning-start (100m).

• Act.SpS-mean value of only 0.12mm does not correspond to the SpS-mean value. The yarn clearercaptures the yarn count completely wrong. We must assume that the measuring slot is dusty and because ofthe high default values (?), the dyn.dust compensation insufficiently corrects. Caused by a worsening yarn,the yarn breaks. The system compensated shortly after the newly pieced yarn is passed to the yarn clearer,but then a dust particle fell from the measuring slot.

• Dust 0.00mm indicates that no corrections took place. This is unusual and underlines the observation withthe act.SpS-mean value.

• CV% is too high, because the act.SpS-mean value is much too low.

•

Thin places are present in large numbers in both classes "- 20% /160mm" and "- 20% /320mm". Theact.SpS-mean value is mistakenly in the thin place range, thus the thin places are more pronounced.

With the above test only 4475m yarn were produced. With the dust length set to 2000m, the earliest correctioncan take place at 3000m. The following correction would be with 5000m. This is clearly inadequate for this yarn.This test has failed.

5.5.7. Summary

•

Processing PES creates a lot of dust.

• Dust in the measuring slot falsifies the measurement of the yarn diameter.•

The finer the yarn, the larger the problems.

• In order to understand the problem, one must have knowledge of the yarn diameter, the Barco formula

Documents

Technology Handbook 2006