USTER TESTER 5-S800 - Think Quality · 3 Challenges for slub yarn spinners . Besides the challenges of the slub yarn industry today, discussions with many slub yarn spinners revealed

Sandra Edalat-Pour March 2008 SE 614

USTER® TESTER 5-S800 APPLICATION REPORT Measurement of slub yarns Part 2 / Experience in mills

THE YARN INSPECTION SYSTEM


Copyright 2008 by Uster Technologies AG All rights reserved. No part of this publication may be reproduced, stored in a re-trieval system, translated or transmitted in any form or by any means, electroni-cally, mechanically, photocopying, recording or otherwise, without the prior permis-sion in writing of the copyright owner. veronesi\TT\Schulung_Dokumente \Off-Line\Uster Tester5\SE_SD-614_Measurement of slub yarns_Part 2\SE_614.doc

2 (32) USTER® TESTER 5-S800


Contents

1 Introduction ................................................................................ 4

2 Description of the slub yarn industry today............................ 4

3 Challenges for slub yarn spinners ........................................... 6

4 Typical faults and recommendations how to detect them ..... 6 4.1 Slub yarns not meeting the requirement ...................................... 6 4.2 Outliers......................................................................................... 8 4.3 Yarn mix-ups ................................................................................ 9 4.4 Periodic faults............................................................................. 10 4.5 Repeat patterns.......................................................................... 12 4.6 Summary of typical faults and aspects of slub yarns and

recommendations for their analysis ........................................... 14

5 Correlation of yarn results and fabric appearance ............... 15 5.1 Ring-spun yarn........................................................................... 15 5.2 Open-end rotor yarn................................................................... 17

6 Influences on slub yarns ......................................................... 18 6.1 Influence of the raw material ...................................................... 18 6.2 Influence of the winding process................................................ 20 6.3 Influence of slub yarn devices.................................................... 21

7 Re-design of slub yarns .......................................................... 21 7.1 Comparison of original and duplicated slub yarn (1) .................. 22 7.2 Comparison of original and duplicated slub yarn (2) .................. 24 7.3 Analysis of short pieces of slub yarns ........................................ 26

8 Testing plan for slub yarns ..................................................... 27

9 Tensile measurements of slub yarns ..................................... 28 9.1 Comparison USTER® TENSORAPID vs. USTER®

TENSOJET ................................................................................ 29 9.2 Determination of the effective strength of a slub yarn ................ 30

10 Summary................................................................................... 31

USTER® TESTER 5-S800 3 (32)


1 Introduction In June 2007, the new evaluation tool for the USTER® TESTER 5, the so-called Fancy Yarn Profile, was introduced to the market. It fulfils the re-quirements of slub yarn producers, knitters, traders and retailers. On the one hand side, characteristics of slub yarns are determined accurately, which are needed for the negotiations between slub yarn spinners and their customers. On the other hand, the spinner can use the measurement re-sults to analyse their slub yarns and to control and improve their quality from day to day, from machine to machine and from lot to lot. The first application report (SE 596) explained the various parameters, graphs, and statistical values. Furthermore, the operation and settings of the software were explained. The present application report (SE 614) deals with the first field experi-ences with this tool, how to use its results to detect typical faults, shows correlations between fabric appearance and yarn parameters, and com-pares different systems. Furthermore, related subjects are explained like the tensile measurement of slub yarns. 2 Description of the slub yarn industry today The denim industry is truly an international industry. Virtually all primary denim manufacturers have plants on various continents, joint ventures, etc. Mills can have direct plants in several countries and further partners in other countries or areas that also deliver yarn to the headquarters for fur-ther processing of the yarn. The mix of regions and manufacturing equip-ment makes the requirement to produce repeatable and consistent denim fabrics especially challenging. Furthermore, denim plants can be separated into two categories. These are verticals that manufacture yarn through fabric and sales yarn manufactur-ers who only provide yarn. The need to provide these unique slub yarns leads to a very unique relationship. In many ways the design and prepara-tion of the fashion focused effect is hard to develop and even harder to con-trol. The knowledge of the slub yarn manufacturers vary greatly. Some are in the business for many years and know this area very well. Others have just started producing slub yarns and are still building up their experience. Some spinners might have slub test instruments for the analysis of the slub yarns, whereas most spinners use parameters of regular yarn measure-ment to analyze their slub yarns roughly or check the yarn just by cutting and weighing.



The cycle of designing new fashions and fabrics is the key challenge for the industry. Mills have to meet both appearance and as well as cost require-ments. The desired appearance need is obvious and must be met to be sold. The cost issue is much more complex. The following considerations seem to be especially critical.

• Type of yarn – Ring spun or open end?

• Are there existing yarn/fabric samples that can be used for reference?

• Count of yarn – Considering the effects, what is the proper base yarn count?

• Runability – Can the fabric be economically produced? How can this be evaluated quickly? How can the runability be improved by influencing the base yarn count, slub size, etc.

This often becomes a trial and error process. A typical product develop-ment cycle time today is approximately 6 weeks for the best and most ex-perienced denim producers. It is clear that the prediction of efficiency and cost is a major issue. The settings for the slub insertion systems onto the ring spinning and open end spinning vary greatly for a variety of reasons. Basically the system is “open loop” and no quantifiable method exists within the system to assure the desired effect is being created. The type of spinning frame, length of spinning frame, count of roving, count of yarn, raw material, combed or carded process, etc. will all induce a need to modify settings. Therefore, objective and quick measurement of the final effect is vital. The slub insertion system electronic controls directly an entire spinning frame or at least individual electronic (drive motors) control 25% of the frame. The significance is that a proper or defective slub is duplicated on each position simultaneously. For example, on a 1,200 position ring spin-ning machine each position is making the slub and a 360 position OE ma-chine each position is making the slub, whether good or bad. This com-pares to traditional laboratory quality control testing where individual posi-tions are key. Therefore, in an optimum situation each unit which produces slub yarn must be checked systematically against standard fancy yarn standards and references. All these influencing factors show the need for a standardized measure-ment and standard parameters for a clear communication between spin-ners, weavers, knitters, traders and retailers.



3 Challenges for slub yarn spinners Besides the challenges of the slub yarn industry today, discussions with many slub yarn spinners revealed the most frequent problems they have to face in the daily production of slub yarns. These are:

• Slub yarns not meeting the requirements / set standards

• Randomness of the intended slub effect

• Yarn mix-up (wrong bobbins)

• Repeat patterns / wrong setting of slub programme

• Mass decreases related to the slub (before or after the slub)

• Defining settings for different slub insertion systems that should pro-duce the same slub yarn

• Relating the settings of the slub insertion system to characteristics / parameters of a slub yarn and eventually relating them to the fabric ap-pearance

The USTER® TESTER 5 Fancy Yarn Profile was especially developed to help the spinners with such kind of problems in order to be able to establish a quality management for the special requirements of the slub yarns. Chap-ter 4 presents some of these faults and gives recommendations which fea-tures of the USTER® TESTER 5 Fancy Yarn Profile can help to detect and eliminate such faults. 4 Typical faults and recommendations how to de-

tect them In this chapter, some typical faults are described in detail. At the end of the chapter, there is a summary of the most common faults of slub yarns and which feature of the “Fancy Yarn Profile” is most suitable to detect the re-spective faults. 4.1 Slub yarns not meeting the requirement It is possible that slubs are not being produced correct or are even missing over a certain length. Depending on the cause, the distance without slubs can be longer or shorter. This kind of fault will hardly influence the mean values of numerical results, but it will show up in high values for the slub distance max and it will be visible in the mass diagram.



Missing slubs over a long distance The example shown in Fig. 1 and Fig. 2 shows the result of a yarn, on which the slubs were not produced over a length of almost 40 meters. This can be considered as a serious fault as it has damaging effects on the fab-ric appearance later on.

Fig. 1 Numeric table with long “slub distance max”

Fig. 2 Mass diagram with missing slubs over a long distance

Slubs not being produced correctly Fig. 3 below shows an example of a yarn that contains certain slubs which are not produced correctly, i.e. the mass increase of the slubs is too low. A possible source for this fault may be, when the drive of the slub insertion system which is not strong enough to produce the slubs over the whole machine as defined in the slub program. Also, this kind of fault will become visible in the fabric appearance later on.

Fig. 3 Missing slubs in the diagram



4.2 Outliers An outlier is defined as a slub, which does not meet the defined specifica-tions regarding the slub length and the mass increase of the slub. Outliers can easily be detected in the slub scatter plot or in the result table as num-ber of outliers per km. In order to get this data, populations must be defined in the Fancy Configuration dialog. The definition of these populations re-sembles the specification of the slubs, i.e. the size of the slubs that is ex-pected. Fig. 4 shows the numeric values for the number of outliers in the result ta-ble, whereas Fig. 5 shows the outliers in a graphical form in the slub scatter plot.

Fig. 4 Numeric table with outlier information

Fig. 5 Scatter plot with outliers

outliers



By analyzing the mass diagram, the reason for these outliers becomes ob-vious: often, slubs were not separated clearly during the production, i.e. the slub distance between the slubs was missing.

Fig. 6 Mass diagram, outlier

outlier

We recommend defining populations for slub yarns even if only one type of slub is produced in a yarn. Only if a population is defined, the number of outliers is given in the result table. 4.3 Yarn mix-ups A serious fault is the mix-up of yarns, i.e. wrong bobbins are wound to-gether on the winding machine. In the example shown below (Fig. 7 and Fig. 8), two different kinds of slub yarns were wound together on the wind-ing machine. This will lead to severe changes in the fabric and thus must be detected and eliminated as early as possibly. In this case, the mix-up of two yarns becomes visible in the mass diagram as well as in the sequence diagram.

Fig. 7 Mass diagram of two differ-ent slub yarns on a cone

Fig. 8 Sequence diagram of two different slub yarns on a cone



In another example, two different slub yarns were found in one batch. As the mass increase is the same for the slubs of both yarns, the difference is not visible in the diagram, but it becomes visible in the scatter plot of the yarn (Fig. 9).

Fig. 9 Scatter plot of two different slub yarns in one batch

4.4 Periodic faults Like in regular yarns, it is possible that slub yarns also have periodic faults from defective turning parts of the spinning machine or turning parts of prior processes. Up until now, the mass spectrogram gave the information from the yarn as it was measured. With the new “Fancy Yarn Profile” however, it is possible to separate the yarn into base yarn and into slubs. This can be especially useful in case of the spectrogram. Fig. 10 shows the mass spectrograms of a slub yarn (100% cotton, ring spun yarn) as it was measured by the capacitive sensor. According to the limits which derive from regular yarns, some areas are marked red, which indicates that there is a periodic or nearly periodic fault.

Fig. 10 Spectrograms, combined



As described before, the base yarn can be separated from the slubs. In the spectrogram it looks like the following two figures.

Fig. 11 Spectrogram, slubs only

Fig. 12 Spectrogram, slubs removed

By analyzing the two separate spectrograms (Fig. 11

Fig. 11

and Fig. 12), it be-comes clear that the regular mass spectrogram of Fig. 10 (spectrogram, combined) does not contain any periodic faults. The areas marked red de-rive from the center-to-center distance of the slubs as it can be seen in

, which shows the spectrogram of the slubs only. The spectrogram of the base yarn, however, shows that there is a periodic defect in the base yarn, deriving from a defective front roller of the ring-spinning machine. This could not have been detected with the regular spectrogram which combines the spectrogram of the base yarn and the spectrogram of the slubs. With this tool, it becomes easy to detect periodic faults even in slub yarns!



4.5 Repeat patterns One of the most critical faults are repeat patterns. They are caused by wrong settings of the slub program. They cannot be recognized in the regu-lar diagram of any numerical value. They can only be detected in the se-quence diagram.

Fig. 13 Sequence diagram with repeat pattern

Table 1 shows the positions and corresponding distances between the re-peat patterns. As it can be seen in the sequence diagram, there are always two slubs repeating after a short distance and then, the pattern repeats itself after a longer distance again. The information given in the table below can be achieved by placing the cursor over the respective position in the sequence diagram.



Slub Position Difference be-tween positions Distance [m]

Distance between repeats

[m]

95 - 22 -

105 10 24 2

225 120 51 29

245 20 55 4

345 120 77 26

355 10 81 4

475 130 107 30

495 20 111 4

595 120 135 28

605 10 137 2

725 130 164 29

745 20 167 3

840 120 191 27

850 10 194 3

Table 1 Calculation of repeat pattern

The evaluation shows clearly, that there is a long repeat pattern every 130 and 120 position, i.e. every about 27 – 29 m and a short repeat pattern af-ter 10 and 20 positions, i.e. every about 2 – 4 m. With this example it becomes obvious that the sequence diagram is a valu-able tool to recognize repeat patterns that could not be detected otherwise.



4.6 Summary of typical faults and aspects of slub yarns and recommendations for their analysis

Table 2 gives a summary of typical faults and aspects of slub yarns and gives recommendations which features of the Fancy Yarn Profile can be used to control them or to find the faults efficiently.

Typi

cal f

aults

/ as

pect

s of

slu

b ya

rns

Num

eric

val

-ue

s

Mas

s di

agra

m

Sca

tter p

lot

Seq

uenc

e di

a-gr

am

3D H

isto

gram

Cla

ssifi

catio

n M

atrix

Spe

ctro

gram

His

togr

am

Lim

its

Long

term

re

port

Check of specifica-tions/key figures*

x x x x x x

Daily quality control x x x x x

Development of a new slub yarn

x x x x

Mass decreases related to slubs

x x x

Outliers x x x x x x Prediction of base count / slub count

x

Repeat pat-terns x

Periodic faults (short term)

x

Longterm faults / peri-odic faults (long term)

x x

Yarn mix-ups x x Visualization of slub distri-bution

x x x

Missing slubs / con-secutive slubs

x x

Table 2 Typical faults and as-pects of slub yarns and recommendations for their analysis

• Key figures like: slub length, slub distance, mass increase, ratio T/B, number of slubs/m, etc.



5 Correlation of yarn results and fabric appear-ance

In this chapter one ring yarn and one open-end yarn are shown together with their numeric results, a picture of the corresponding fabric made out of this yarn and the simulated fabric out of the measurement results with the USTER® TESTER 5 simulation software. The real fabric was made out of the same yarn, but not from the tested piece. The USTER® TESTER 5 uses the data from the mass diagram directly for the fabric simulation. The fabric simulation can be used to get a first im-pression of the yarn appearance in the woven fabric, but also in a knitted fabric or on a blackboard or on a taper board. Different kind of fabrics can be designed in order to get as close to the anticipated fabric appearance as possible. For the following two simulations, the slub yarn was only used in weft direc-tion. For the warp, a plain yarn was used. 5.1 Ring-spun yarn Fig. 14 to Fig. 16 show a ring yarn with its numeric results, the real fabric as well as the simulation. It becomes visible how the short slubs with a low mass increase appear in the real fabric as well as in the fabric simulation.

Fig. 14 Result table



Fig. 15 Picture of real fabric

Fig. 16 Fabric simulation of the USTER® TESTER 5




5.2 Open-end rotor yarn The example below shows an open-end rotor yarn with long slubs. They can be identified in the picture of the real fabric (Fig. 18) as well as in the simulated fabric (Fig. 19).

Fig. 17 Result table

Fig. 18 Picture of real fabric


Fig. 19 Fabric simulation of the USTER® TESTER 5

6 Influences on slub yarns There are many aspects which influence the appearance of slubs irrespec-tive of the settings of the slub yarn device. Some aspects are described in this chapter. 6.1 Influence of the raw material Fig. 20 and Fig. 21 show the scatter plot of a carded yarn versus a combed yarn. The settings of the slub yarn device are identical as well as the nomi-nal count of the yarn. But it becomes visible that the carded material has higher variations for the dimensions of the slub than the combed material, although the mean values of the slub length and the mass increase are the same. This will clearly have influence on the fabric appearance later on.



Fig. 20 Slub yarn, carded

Fig. 21 Slub yarn, combed



6.2 Influence of the winding process Fig. 22 and Fig. 23 show the influence of the winding process on a slub yarn. The key figures of the slub (slubs/m, slub length, slub distance, mass increase, ratio T/B) stay on the same level. Outliers for example can be eliminated during the winding process.

Fig. 22 Slub yarn on bobbin

Fig. 23 Slub yarn on cone



6.3 Influence of slub yarn devices

Fig. 24 and There are several suppliers of slub yarn devices on the market. Fig. 25 show the mass diagram of two yarns that are supposed to be the same. The yarns were produced on the same type of spinning machine, but on two different kinds of slub yarn devices. Differences between the two yarns become obvious.

Fig. 24 Slub yarn device A

Fig. 25 Slub yarn device B

The differences between the two yarns must be corrected by adjusting the settings of the slub yarn devices accordingly. 7 Re-design of slub yarns The reproduction of slub yarns is an important issue for slub yarn produc-ers. Besides the new design of slub yarns, existing slub yarns need to be duplicated. The USTER® TESTER 5 does not provide a direct copying func-tion, as the appearance of a slub yarn depends on many parameters. Thus, it is required from the producer of slub yarns to “translate” the results of the USTER® TESTER 5 into the different kind of slub yarn devices, raw materi-als, and spinning machines. This chapter describes how the USTER®

TESTER 5 can support the re-design of slub yarns.



7.1 Comparison of original and duplicated slub yarn (1) Fig. 26 shows the results and some selected graphs from the original yarn that was measured. According to the original yarn, a configuration was made including the definition of a population, which marks the main area of the slub events.

Fig. 26 Original yarn



Fig. 27 shows the results of the duplicated yarn. It confirms that the dupli-cated yarn still needs some further improvement of the slub yarn device settings. The main areas which need modification are the slub length, slub distance, mass increase as well as the adjustments of the ramps (ratio T/B). It becomes also obvious that the main area of the slubs, as shown in the scatter plot, has a wide variation. The area of the population as defined in the configuration of the original yarn is exceeded considerably.

Fig. 27 Duplicated slub yarn



This comparison shows how the results of the USTER® TESTER 5 Fancy Yarn Profile can help to analyze a yarn in order to adjust the settings of the slub yarn device accordingly. 7.2 Comparison of original and duplicated slub yarn (2) In another example, the original yarn and the duplicated yarn were com-pared. The appearance of the two yarns was different, although, on first sight, the numeric results as well as the scatter plot did not show substan-tial differences between the two yarns. Fig. 28 shows the results of the original yarn, whereas Fig. 29 shows the results of the duplicated yarn.




Fig. 29 Duplicated yarn

As the numeric results as well as the scatter plot did not show any differ-ences between the two yarns, the slub distance histogram as well as the slub sequence diagram were analyzed (Fig. 30 and Fig. 31).




Fig. 31 Duplicated yarn

With the help of the slub sequence diagram and the slub distance histo-gram the difference between the two yarns became obvious. Periodic re-peat patterns cannot be recognized in the numeric values. Also, the scatter plots are not influenced by such characteristics. For the duplication of slub yarns it is important that all slub parameters are analyzed thoroughly before the duplicated yarn can be released for produc-tion. 7.3 Analysis of short pieces of slub yarns The USTER® TESTER 5 provides a test mode that is called “Short test length”. This is a feature that can be used when only short pieces of yarn are available and need to be analyzed. The test mode “Short test length” can also be used for the material class “Fancy Yarn”. Pieces of yarn, e.g. taken out of a fabric can be knotted together and then connected to a dif-ferent yarn on a bobbin or cone. This other yarn can be either a slub yarn or a regular yarn. A total yarn length of 50 m is required for this special test method (yarn to be analyzed plus regular yarn). When a regular yarn is used, the numerical values of the slub evaluation can be used as well as the scatter plot and the classification matrix. Fig. 32 below shows two diagrams. The first one shows the diagram over the whole test length, whereas the second diagram shows only the first part of the zoomed-in diagram. This is the part where the short yarn pieces were knotted together. The knots are indicated with an arrow.



Fig. 32 Mass diagram for a test with “Short test length”

If such a test is carried out, we recommend checking mainly the diagram for detailed analysis of the slubs as the numeric values will be calculated over the whole test length. Therefore, only the mass diagram should be con-sulted for the key figures of the slub yarn. 8 Testing plan for slub yarns Ring spinning machines or OE spinning machines that are producing slub yarns usually consist of one slub control unit and up to four sections with independent driving systems to feed the additional fibers into the spinning zone. This can lead to the fact that a malfunctioning drive system possibly ruins the production of a complete section of the spinning machine!

Fig. 33 Sections of a ring-spinning machine for slub yarn pro-duction

Fig. 34 Sections of a OE machine for slub yarn production

Therefore, it is of utmost importance that the spinning positions of each section are checked regularly to make sure that not half or a quarter of the production is out of the specifications and must be thrown away. The test-ing plan below (Fig. 35) is a suggestion how the testing procedure could be organized. It assumes a production of slub yarns on 18 OE-spinning machines and on 34 ring-spinning machines. Besides, there is also a production of regular yarn.



Slub Testing

Machine Type Machines

Sections per

machinePackages

Tested

Total number of packages

Frequency per week

Tests Total

OE Spinning 18 2 5 180 2 360

Ring Spinning 34 4 5 680 2 1360

Total Tests 860 1720

UT5 S-400 hours required 43 86UT5 S-400 shifts (8hrs) required 10.8

UT5 S-800 hours required 29 57UT5 S-800 shifts (8 hrs) required 7.2

Standard Testing - Yarn

Machine Type Machines

Sections per

machinePackages

Tested

Total number of packages

Tests Total

OE Spinning 67 1 5 335 2 670

Ring Spinning 70 1 5 350 2 700

Total Tests 685 1370



Total


UT5 S-800 hours Required 52 103UT5 S-800 shifts (8hrs) required 12.9

Fig. 35 Testing plan for a UT5 S400 and S800

This testing plan also shows the advantage of a USTER® TESTER 5 S800 over a USTER® TESTER 5 S400. The time for the routine testing of regular yarn and slub yarn can be reduced by one third leaving time for other labo-ratory work and checking exceptions that were found with the yarn clearer. 9 Tensile measurements of slub yarns Besides of the appearance of a slub yarn, the performance on the weaving machine is also very important as it affects the costs of the subsequent processes considerably. The purpose of the Fancy Yarn Profile of the USTER® TESTER 5 is to analyze the slub yarn in regard of appearance and faults and to provide a quality control tool for the spinner. The purpose of the USTER® TENSOJET, however, is to verify that the slub yarn does not contain any weak places which could lead to frequent stops on the weaving machine and causing loss of weaving efficiency.



9.1 Comparison USTER® TENSORAPID vs. USTER® TEN-SOJET

The USTER® TENSOJET is a high-speed strength tester for staple-fiber yarns. Due to the measurement speed of 400 m/min a high number of tests can be carried out in a very short time. A regular test consists of 10 x 1000 tests, which results in 10’000 tests in less than 25 minutes! Thus, the major advantage of this system is that weak places and outliers can be detected easily. In a special trial in Uster, a yarn was first tested on the USTER® TEN-SORAPID with 2500 tests, which is already a very high number of breaks for this instrument. Two populations can be separated, which show the strength of the base yarn as well as the strength of the slubs.

Fig. 36 Scatter plot USTER® TENSORAPID

Slubs

But the results of the scatter plot of the USTER® TENSOJET (Fig. 37) makes it clear that even more breaks are necessary in order to find the weak places in the yarn that will result in stops on the weaving machine causing low efficiency. Numerous breaks which show an elongation below 3% and strength below 300 cN are detected during a regular test of this instrument.

Fig. 37 Scatter plot USTER® TENSOJET

Base yarn

Weak places

Base yarn

Weak places

Slubs

Fig. 37 shows the scatter plot with a total of 9,968 breaks. The occurance of weak places can be seen very clearly.



9.2 Determination of the effective strength of a slub yarn For this test an open-end yarn with long slubs was measured on the USTER® TESTER 5 in order to find out the base count and the slub count. The count of the slubs was Nm 8.4 (Ne 5 or 70 tex), the count of the base yarn was Nm 20.5 (Ne 12 or 29 tex). The nominal count was Nm 17 (Ne 10 or 59 tex). It is important to know that the count of the slubs and the count of the base yarn will get more accurate, when the FA-module is used and the count is measured accurately instead of using the nominal count for the calculation of the slub count and base count.

Fig. 38 Results of the count meas-urement/calculation on the UT5

The results of the regular strength measurement on the USTER® TEN-SORAPID are shown in Fig. 39. As the nominal count was entered, the tenacity was measured at 13.30 cN/tex, the breaking force, which is the directly measured force is 782.3 cN. The stroke diagram of the force, how-ever, makes it clear that the strength of the slubs deviates considerably from the strength of the base yarn. The elongation stays the same for slubs as well as for the base yarn.

Fig. 39 Regular strength measure-ment



In order to find out the strength of the slubs as well as the strength for the base yarn separately, two additional tests were carried out. The results shown in Fig. 40 were reached by manual tests of the base yarn only. Fig. 41 shows the results of the measurements of the slubs only.

Nr Time to break

s

B‐Force

cN

Elong.

%

Tenacity

cN/tex

B‐Work

cN.cmMean 0.33 664.6 8.98 22.92 898.3s 0.02 43.48 0.38 0.74 279.5CV 5.4 6.5 4.3 6.5 31.1Q95 0.00 8.63 0.08 0.15 55.46Min 0.26 573.5 7.18 9.75 677.1Max 0.40 802.8 9.72 13.65 2816

Fig. 40 Strength measurement of the base yarn

Nr Time to break

s

B‐Force

cN

Elong.

%

Tenacity

cN/tex

B‐Work

cN.cmMean 0.38 1752 10.58 25.03 2513s 0.02 119.9 0.48 2.04 270.7CV 4.5 6.8 4.5 6.8 10.8Q95 0.00 23.79 0.09 0.40 53.72Min 0.31 1151 8.59 19.57 1338Max 0.42 2009 11.51 31.15 3179

Fig. 41 Strength measurement of slubs only

The tenacity of the slubs vs. the tenacity of the base yarn lies within the normal range of variation. No general statement about the strength of slubs and base yarn can be made out of this trial. With this trial it becomes obvious that the value of the tenacity of a slub yarn cannot be used at a regular test as the count of the slubs and the count of the base yarn are different and the nominal count does not con-sider this fact. Therefore, only the breaking force can be used in case of slub yarns, as this value is actually measured on the instrument. 10 Summary This application report shows that the measurement of slub yarns is a com-plex field and must be studied carefully. The new evaluation option Fancy Yarn Profile of the USTER® TESTER 5 as well as the other instruments of Uster Technologies support the analysis and the daily production of these yarns in order to prevent faults and to guarantee that the slub yarns meet the defined requirements.


32 (32)


Uster Technologies AG Wilstrasse 11

H-8610 Uster / Switzerland C Phone +41 43 366 36 36

ax +41 43 366 36 37 F www.uster.com [email protected]

USTER® TESTER 5-S800

Documents

USTER TESTER 5-S800 - Think Quality · 3 Challenges for slub yarn spinners . Besides the challenges of the slub yarn industry today, discussions with many slub yarn spinners revealed