Southeast University Southeast University Department Of Textile EngineeringDepartment Of Textile Engineering

I/A 251,252 Tejgaon Dhaka BangladeI/A 251,252 Tejgaon Dhaka Bangladesh sh

Function/objectives/What it Function/objectives/What it does?does?

• The chief function of roving frame is the attenuation of sliver.

• Insertion of protective twist in order to hold the fine strand of sliver.

• Winding of roving into a package that can be transported, sorted, donned on ring spinning machine.

Limitations/Draw backsLimitations/Draw backs• Complicated machine

• Liable to faults• Causes defects• Add to production costs• Roving is sensitive in both winding & unwinding

• Complicated winding operations• Spindle & flyer• A cone drive transmission• A differentiate gear• Builder motion.

Necessity of Roving FrameNecessity of Roving Frame

• There are two principle reason:– First reason is to apply drafting.

– Sliver is thick, untwisted strand that tends to be hairy and to create fly. There fore, if we directly want to produce yarn from sliver by discarding simplex, we need 300 to 500 draft to do so. But the fine twisted roving is significantly better suited to this purpose.

– Second reason is related with transportation and space limitation on ring frame.

– Draw frame “can” is the worst conceivable mode of transportation and presentation of feed material.

Operating region of Roving frameOperating region of Roving frame The creel The drafting arrangement

Roller drafting system

The apron Applying pressure to

the top roller. The condenser The spacer

Winding of bobbin Package build Bobbin drive

Cone drive transmission The lifter motion The builder motion

Spindle & flyer Imparting

twist Spindle Flyer Design of flyer Pressure arm

Drafting arrangement of roving frameDrafting arrangement of roving frame

• Roller Drafting system– Conventional roller drafting system:

– 4 over 4 without apron.

– Modern Roller drafting system: – 3 over 3 drafting system with double apron (Lakshmi Rieter

FS185P)– 4 over 4 drafting system with double apron (SKF PK 1600)

SKF PK-1600 drafting systemSKF PK-1600 drafting system

• Draft range: Total draft 5 to 20• Total draft is distributed in each zone as follows:

– Back zone: Break draft is applicable in here. Amount of break draft is

depends upon material.Material Break Draft

Sliver Coarse 1.5-1.4

Sliver Medium 1.4-1.3

Sliver Fine 1.3-1.2

Sliver MMF 1.2-1.1

• Middle zone: – Less amount draft is applicable in here. – Condenser is used in middle zone to condense sheet like sliver.

• Front zone:– Maximum amount of draft is applicable in here. Apron is

used in this zone.

• Roller type:– Top rollers are synthetic rubber coated– Bottom rollers are made of steel– Front, 3rd and back rollers (bottom) are spiral fluted. – 2nd roller has granulated pin.

• Roller dia:

Roller Front roller 2nd roller 3rd roller Back roller

Top roller 28 mm 25 mm 28 mm 28 mm

Bottom roller 30-32 mm 25-27 mm 30-32 mm 30-32 mm

The Apron:The upper aprons are short and made either of leather or more commonly of synthetic rubbers. They have a thickness of about 1 mm and are held by tensioning device.

The lower aprons are longer and usually made of leather. They run over the guide bar, usually known as nose bar, to position close to the delivery roller.

Function:The aprons co-operated with each other t guide and transports the fibers during drafting and they exert a very significant influence on the drafting operations.

Applying pressure to the top roller

• The top roller must be pressed with relatively high force against the lower rollers to ensure the guidance of fiber.

• Pressure are in the range of 100 to 250 N per roller which may vary as per raw material and its volume.

• Pressure is applied by spring pressure, pneumatic weighting, magnetic weighting.

CondenserCondenser

Feature:•Condensers are mounted on a reciprocating bar behind the drafting arrangement.•The second condenser is provided in break draft field.•And the 3rd one is located in main draft field. Function:•Spreading sliver masses are condensed to improve evenness and lead to drafting zone. Advantage: •Reduce the high fly level and hairiness of roving.

SpacerSpacer

• As the top apron are forced by spring pressure against the lower apron, the arrangement of this apron should permit precise adoption of minimum distance to fibre volume. In order to be able to maintain this minimum distance, spacer are replace ably inserted between the nose bar of the lower apron and the cradle edge of top apron. Spacer size is 4 to 7 mm in accordance with roving hank.

Imparting TwistImparting Twist

The flyerThe flyer

• Flyer is used to impart twist• Flyer has two legs, one with hollow path or

slot and pressure arm another for balancing the flyer while rotating.

• Flyer is placed on spindle, it gets motion by gearing.

• Flyer speed has direct influence on production.

• Flyer can be varying in sizes which are specified in inch. For example, 12”X 5.5”, 12”X6” and 14”X6”. First no. indicate maximum height and second no. indicate maximum dia of wound package.

Pressure ArmPressure Arm

• A steel yoke attached to the lower end of hollow flyer leg is called pressure arm.

• The roving is wrapped 2 or 3 times around the yoke. • The no. of turn determine the roving tension. For higher

tension, a hard compact package is obtained and if it is too high false draft or roving breakage can be caused.

• Therefore, the no. of wrap depends upon material and twist level.

Winding PrincipleWinding Principle

• Bobbin leading principle (For cotton spinning)• Flyer leading principle (For jute spinning)

Bobbin leading PrincipleBobbin leading Principle

• Bobbin speed is higher than flyer speed at all point of winding.

• The winding on speed is constant throughout the process.

• With the increase of bobbin dia, bobbin speed must be decreased.

• The variation of bobbin speed with the increase of bobbin dia must be constant.

• Less tension on roving. RPM

d

Empty Bobbin

Full Bobbin

BobbinSpeed

Flyer Speed

Flyer Leading PrincipleFlyer Leading Principle

Flyer Speed

Empty Bobbin

Full Bobbin

BobbinSpeed

• Flyer speed is higher than bobbin speed at all point of winding.

• The winding on speed is constant throughout the process.

• With the increase of bobbin dia, bobbin speed must be increased.

• The variation of bobbin speed with the increase of bobbin dia must be constant.

• Higher tension on roving.

Recent Development of Speed FrameRecent Development of Speed Frame1. Improved drafting system:

Modern drafting system like SKF PK 1600, SKF PK 5000 etc give more controlling to fibre and they able to import 8 to 20 draft on sliver.

2. Higher flyer speed:Modern flyer speed is more than 1000 rpm where as the convention flyer reaches maximum 600 rpm.

3. Plastic flyer: lighter in weight and less power consumption in result.

4. Flyer driving from top: Modern flyers are top mounted and having no spindle which in

turns facilitate following issues:Auto doffing operationReduced flyer leg spreadingHigher flyer speed

5. Inching motion: It initiates flyer turning slowly for piecing if the end breaks. And also ensures less tension on roving while the machine starts.

6. Auto stop motion:Various auto stop motions are initiates to reduce waste and increase efficiency: Sliver stop motion, Roving stop motion, Creel stop motion, full bobbin stop motion, Doffing stop motion.

7. Pre determine set length: Machine stops automatically after a predetermined length of

roving is wound on bobbin.

8. Monitoring system: Modern speed frame includes data monitoring system by direct reading of :production, efficiency, speed of flyer, stoppage time, quality monitoring and package built.

9. Auto doffing: Like some ring spinning machine, simplex machine manufacturers offer the machine having automatic doffing system where full

bobbins are replaced by empty bobbin without any help of worker.

10. Automatic tension controller: it determines the tension on roving continuously and send data to inverter to adjust its speed.

Faults in speed frameFaults in speed frame:• Irregular roving

• Irregular draft• Top roller dia variation• Pressure variation. • Rough surface of apron• Improper roller setting

• Roving Breakage:•Irregular roving•Tension variation•Variation of pressure on top roller

• Sloughing off:•Improper taper end•Faulty taper wheel

•Roller lapping:•Stickiness formation on roller•Wet roller surface•Excessive dry roller surface•Dust deposit on roller.

•Unequal tapering:•Wrong angle of poker rod•Different lifting and lowering distance due to faulty builder motion

•Soft bobbin:•Winding on speed is less than front roller delivery•Less tension on roving during winding•Less coil/inch (if top rail speed is too high it results excessive spacing between adjacent coil.)

•Dirty roving bobbin:•Excessive oiling on machine parts•Insufficient machine cleaning•Cracked bobbin and careless handling

ComberComber

FunctionFunction

Remove neps and foreign matter form the cotton.

Improve fibre parallelization and fibre to fibre separation and minimize the fibre entanglement and disorientation.

Remove short fibre below a preselected length and there by reduce length variation in the cotton mixing.

Excellence of fiber quality by Excellence of fiber quality by combingcombing:

Parameter/ Specification of Parameter/ Specification of combercomber

• Feed/nips 6-8 mm• Nips/min 220-600• Lap weight800-1200 grs/yd• Noil % 10-25%• Efficiency 90-95%

Line diagram of comberLine diagram of comber

Lap

Feed PlateCylinder

Feed Roller

Top nipper

Bottom nipper

Top combDetaching

roller

Deliveryroller

Machine Setting Depends on Noil Extraction%Machine Setting Depends on Noil Extraction%

• Feed Distance• Type of feed• Detachment setting• Point density on top combs• Piecing

Feed Distance:Feed Distance:

– Feed distance means feed per nip.– Feed distance has a influence on

• Noil• Quality of combing operation• Production rate.

High feed distance increase the production rate but causes deterioration in quality.

Feed distance approximately correlated with fibre length.

Type of feedType of feed

• Forward feed has been chosen for higher production rate when quality requirement is not rigorous with a noil % of 5- 12 %.

• Backward feed has to use for higher quality requirement with a noil % of 12 to 25%

The detachment settingThe detachment setting

• This is the distance between the bite of the nippers and the nip line of detaching rollers.

• Higher detachment setting bring the high elimination of noil

• The detachment setting normally lies in the range of 15 to 25 mm.

The no. of points on combThe no. of points on comb

• Point density and the fineness of needle have to be adopted to the material.

• The needle of top combs have a flattened X-section and are formed with a bend.

• The point density is 23-32 needles per cm.

• Fewer needles are used for higher production with lower waste elimination.

Top comb PenetrationTop comb Penetration

• Higher top comb penetration results higher elimination of noil.

• Lowering the top comb by 0.5mm is followed an increase in noil of about 2%.

• The main improvement is seen in the elimination of neps.

• Over deep penetration may disturb fibre movement during piecing. This results in deterioration of quality%.

PiecingPiecing

• After combing of the fringe protruding from nippers, the detaching roller draws some of the combed feedstock out of the sheet.

• By means of this piecing operation, the roller have to lay these strips of web on top of each other, so that first a coherent web and finally a endless ribbon is obtained.

• This sliver produced in this way has a wave like structure, it exhibits periodic variation.

• By using correct machine setting, it is possible to lay the fringe on each other that unevenness in successive fringes partly cancels out.

Parameter influence the combing operation

• Raw material– Fibre type– Fibre length– Uniformity of fibre length– Fibre stiffness– Moisture content

• Material Preparation– Parallelization of fibers

in the sheet.– Sheet thickness– Sheet Evenness– Orientation of hooks in

the sliver.

Factors associated with M/CFactors associated with M/C

• Condition of machine• Condition of comb• Speed• Operation of combs• Types of sliver forming elements• Accuracy of the setting• Drafting arrangement.

Effect of combing on staple diagramEffect of combing on staple diagram

Before combing After combing

Noil%

Relationship between noil% and improvement of yarn quality

A= Improvement of Yarn Quality in %B= Noil elimination in %a= Yarn strengthb=Yarn evennessc= Yarn imperfection

Sequence of combing cycleSequence of combing cyclea. Lap feeding by feed roller: The lap is fed into the machine between the feed roller and feed plate. The feed roller moves and material passes forward.

b. Lap nipping by the nipper: the nipper moves downwards towards the feed plate, so that the fibres are clamped between them. Cylinder is then ready for combing.

c. Combing by cylinder: The fibres protruding from the lap beyond the nipping point of the two plates, are combed by the passage of rows of needles fastened to a cylinder which revolves and carries away the short fibres, neps and other impurities.

d. Nipper opening and forwarding: the nipper open again and the material combed by the cylinder moves towards the detaching roller.

e. Detaching roller backward movement: when the top nipper reach upwards, the detaching roller have returned parts of previously drawn off stock by means of reverse rotation.

f. Combing by top comb: the top comb penetrate its single rows of needles in to the fibre fringe. Thus top comb perform the combing operation on the upper side of fringe.

g. Detaching roller forward movement: The detaching roller begin to rotate in the forward direction again and draw the clamped fibres out of the sheet which is held first by the feed roller.

h. Waste extraction by brush

Ring FrameRing Frame

Ring Spinning SystemRing Spinning System(Conventional but competitive)

• Ring frame exhibits significant advantage in comparison with new spinning system:– It is universally applicable; ie. Any material can be spun to

any required fineness.

– It delivers yarn with optimal characteristics, especially with regard to structure and strength.

– It is uncomplicated and easy to operate.

– The know-how for operation of machine is well established and accessible to everyone.

– It is flexible as regards to its quantities. (Blend & lot size)

FUNCTIONS/ OBJECTIVESFUNCTIONS/ OBJECTIVES

• Attenuation of roving until the required fineness is achieved.

• To impact strength to fibre strand by twisting it.

• To wind up the resulting yarn in a form that it will suitable for storage, transportation and further processing.

Operating Principle:Operating Principle:•The roving bobbins (1) are inserted in holders (3) on the creel. Guide bars (4) guide the rovings (2) into the drafting system (5), where they are drawn to their final count. The drafting system is at an angle of 45-60° and is one of the most important units on the machine, since it exerts a very considerable influence on the uniformity of the yarn in particular.

•After the resulting thin ribbon of fibers (6) leaves the delivery roller, the twist necessary for imparting strength is provided by spindle (8) rotating at high speed. In the process each rotation of the traveler on the spinning ring (10) produces a twist in the yarn. Ring traveler (9) is also necessary for taking up this yarn onto a tube mounted on the spindle. This traveler - a remnant of the flyer on the roving frame - moves on a guide rail around the spindle, the so-called ring (10). The ring traveler has no drive of its own, it is dragged with spindle (8) via the yarn attached to it. The rotation of the ring traveler lags somewhat behind that of the spindle due to the relatively high friction of the ring traveler on the ring and the atmospheric resistance of the traveler and the thread balloon between yarn guide eyelet (7) and traveler (9).

• This difference in speed between the spindle and the traveler results in the thread being wound onto the tube. In contrast to the roving frame, the ring spinning machine spindle operates with at higher speed than the traveller (9). The yarn is wound up into a cylindrical cop form by raising and lowering of the rings, which are mounted on a continuous ring rail. The layer traverse of the ring rail is also less than the full winding height of the tube. The ring rail therefore has to be raised slightly (shift traverse) after each layer has been wound. For a time, machines were also built featuring shift traverse produced by lowering the spindle bearing plate rather than raising the ring rail. These machines are no longer available today.

Operations involve in ring frameOperations involve in ring frameCreeling:

• Roving bobbin are mounted on creel. There is no gear motion to rotate the creel or bobbin.

• Bobbin is rotated with the creel due to tension of moving generated from drafting zone.

• If moving bobbin doesn’t unwind perfectly then false draft can arise or even end breaks.

Drafting• Drafting operation reduce weight per unit length of

roving. • Roving comes from bobbin are passed through the

drafting zone which has commonly a 3 over 3 drafting roller with double apron.

Twisting:• To hold the fiber into yarn cross section and to develop

strength, spiral turns are inserted along the fibre axis. • Travellers mounted on ring cup, twist the yarn, gets drive

directly from spindle.

Winding: • After twisting the yarn are wound on suitable package.• Layer of yarn are wound on one above another in

different stage on package.• Winding mechanism is performed in a way that it will be

suitable for unwinding as well.

Building:• For proper size and shape of package, the ring rails are lifted

gradually. • The resultant bobbin will be conical shape full bobbin.

Doffing:• After a required length of yarn is wound on the package,

machine is stopped for doffing. • Doffing is the process of replacing the full bobbin by an empty

bobbin.

Block Creeling:Block Creeling:• If all roving bobbin filled on the creel are of same size, then

those bobbin will be exhausted at the same time which will cause machine stoppage and production will be hampered.

• In block creeling arrangement, the total no. of creels are divided in to several no. of groups, then each group contains the roving of same length but differ from adjacent group or block.

• Thus all bobbin will not exhausted at the same time.• So, there is no machine stoppage and production will run

smoothly.

CreelCreelThe bobbin creel is simple in design, but it can nevertheless have an influence on the occurrence of faults.If take-off from the bobbin is not trouble-free, incorrect drafts or even thread breaks occur. This is why bobbin suspension pivots are used nowadays rather than bobbin holders. These are, for example, bolted onto several support rails (triangular tubing (2)) arranged one behind the other along the entire length of the machine, one for each spindle. The pivots, such as the Casablancas model illustrated, feature the actual holding device for the tube in their lower section (6). If ring (5) is pushed right up with the top end of the tube inserted in the pivot, retainer (6) for the bobbin swings out; if ring (5) is pushed upward a second time, holder (6) is retracted again, and the tube, for example when it is empty, can be removed again. The pivots are mounted in ball bearings.Nowadays bobbin creels occupy lots space in terms of width, as very large roving bobbins are usually used.

SpindleSpindle

Figure of spindle specified with different parts:Should be studied from the book of W. klein (Volume :4, page: 9)

Function:• To hold the bobbin tightly to prevent shacking during its revolution.• To help in winding yarn on to bobbin.• It takes part in twisting along with ring and traveller.• A capacity of spinning floor is mainly determined by the no. of spindle.

Influence of spindle on spinning:Influence of spindle on spinning:

• Spindles, and their drive, have a great influence on power consumption and noise level in the machine.• The running characteristics of spindle, especially imbalance and eccentricity relative to the ring, also affect yarn quality and of course the no. of end breakages. • almost all yarn parameters are disadvantageously affected by poorly running spindles.

Precaution regarding spindle:Precaution regarding spindle:

• The mill must ensure at all time that centering of the spindle relative to the rings is as accurate as possible. • Since the ring and spindle form independent units and are able to shift relative to each other in operation, these two parts must be re-centered from time to time.

RingRing

Specification of Ring:Ring is specified by its two dimension:

Internal diameter (Ring dia)Flange Width

Available ring dia (mm) for short staple cotton spinning: 36, 38, 40, 42, 44Flange width depends on flange number.

Flange no. 1 1.5 2

Flange width (mm) 3.2 3.7 4.2

Ring Traveller/ TravellerRing Traveller/ TravellerFunction:•It provides fibre band or the double thread supplied by the feed roller with necessary torsion. •It assists in winding the yarn on to cop with correct tension.

Two types of Traveller:1.C- Shaped traveller

• Used on T-flanged horizontal ring• For cotton Synthetic and blends

2. J-shaped Traveller:•Used in vertical ring•For coarser doubling cotton, acrylic, woolen, worsted yarn.

Spinning geometry with respect to ring and TubeSpinning geometry with respect to ring and Tube

1. Ratio of ring dia “D” to tube dia “d” is 2:1 (ideally)• The ring traveller together with the yarn as a pull element, is

set into motion on the ring by the rotation of spindle. • If the direction of pull deviates too much from the running

direction of the traveller (α <30°), the tension load will be high.

• The pulling tension can be reduced by adapting ring or tube dia (α >30°) during the winding up of the tube.

2. Ration of tube length to ring dia 5:1 (ideally)• The tube length determine the maximum balloon length.

The shorter the balloon the higher the traveller speed can be achieved.

• In practical use, the ideal ratio of tube length to ring dia has been shown to be between 4.5:1 to 5:1.

α

d

D

Yarn guiding deviceYarn guiding device

Lappet:Lappets are mounted directly above each spindle. Lappets are designed to lead the yarn centrally over the spindle axis. The lappet consist of thread guide made of bent wire and a pivoted support arm. The guide is adjustably mounted on support arm to enable centering while the arm itself is secured to lappet rail which extend over the length of the machine. This rail along with the lappet can be raised or lowered.

Function of Lappet:1.Continual up and down movement during winding of the layers.

2. Continual upward shift through a small distance in accordance with the building motion.

Balloon Control ring:The space between the ring and the thread guide is correspondingly long. Thus give a high balloon.

In order to avoid this consequences, balloon control ring are used. Each dividing its balloon into two smaller sub balloon. In spite of its large overall height, the double balloon created in this way is thoroughly stable even at relatively low yarn tension.

The effect of balloon:A high balloon is associated with large balloon diameter, causing space problem. The large balloon dimension lead to relatively high air drug on the yarn in the balloon. This in turn cause increase deformation of balloon curve out of the plane intersecting the spindle axis. This deformation lead to balloon instability.

Separator:Most end down arises from the break of spinning triangle. Because there are very high forces executed on the strand of fibres which haven’t yet been fully bound together. If the break occur in the triangle then the newly created free yarn ends must be drawn to the cop and wound on to it. During this process, the broken ends lashes around the spindle. In absence of protecting device, the broken end would hurled in to the neighboring yarn balloon and would cause a end down on that spindle.

The procedure would be repeated continuously so that a wave of ends down travel along the row of spindle.

Therefore, to avoid this circumstances, separator is used.

Requisites for good running Requisites for good running condition of Ring framecondition of Ring frame

•The ring are perfectly centered with regard to spindle.•The yarn guide eyelet is well centered with regard to the spindle. •The balloon control rings are perfectly centered with regard to spindle•The spindle bearing is in good condition excluding spindle vibration.•The ratio between bobbin diameter, bobbin length and spindle gauge with regard to the ring dia is correct.•Correctly adjustable traveller clearer keep the flange traveller free from fly. •Room climate is favorable for the yarn processed.

Reference: (For Picture & Data Cutesy )

1.Rieter2.Toyota 3.SKF PK 4.More …….