analysis of rejected ring cops in autoconer winding machine

Bangladesh University of Textiles

Tejgaon , Dhaka

Project Work on

“Analysis of rejected ring cops in Autoconer Winding Machine”

Supervised by :

Dr. Mohammad Ali

Associate Professor & Head

Industrial & Production Engineering (IPE)

Bangladesh University of Textiles (BUTex)

Submitted by :

Taukir Kabir Tusar (ID : 2011-1-169)

Dept.of Yarn Manufacturing Engineering (YME)

1

AcknowledgementFirst of all, our gratefulness goes to Almighty Allah who gave us strength and ability to complete the project work and prepare this report.

We would like to pay special thanks to Dr. Mohammad Ali, Associate Professor, Head of the department of Industrial Production and Engineering, Bangladesh University of Textiles, for continuously guiding us about the development and preparation of this report . He has enriched us with necessary ideas and concepts for improvement of the report.

We would also like to express our heartfelt thanks to Dr. Hosne Ara Begum , Associate Professor & Head of Department of Yarn Manufacturing Engineering , Bangladesh University of Textiles for all necessary information for preparing this report .

We would like to express our sincere gratitude to Moksed Alam Tonmoy , Deputy Manager , Badsha Textiles Limited & Golam Rabbani , Assistant General Manager , SQUARE Textiles Limited who has allowed us to work in their organization in a congenial atmosphere . Their valuable opinion has enriched our knowledge to carry out the project and portray the information in a logical sequence.

2

AbstractThis work describes the causes of rejections of rejected ring cops in autoconer winding machine with assessment of various experimental datas from various quality instruments . This causes includes count variation , co efficient of variation (CV%) , Thick and thin places , neps , slubs , hairiness and some miscellunous causes like oil stained yarns , crackers in yarns , half and excess full cops , coca cola shaped cops etc . This work also suggest a few ways to solve the problems and to reduce the rejection rate of cops in an acceptable range . Sufficient amount of figures and graphs are also included here to make this work more accurate .

3

Contents

4

Content No Chapter Name Page No

01 Introduction 6-8

02 Literature Reviews 9-14

03 Experimental Work 15-45

04 Conclusion 46-47

05 Reference 48-49

5

Chapter 1 Introduction

6

Introduction

Winding is the last process that is involved in the production line of a spinning factory , specially in the ring yarn production line . It has a number of parameters and variables – embraces different technologies and improving the winding operational productivity and efficiency by the developments in several sciences and fields, such as machinery , materials science, automation and control. On the ring cops obtained from ring spinning machine , contains a very small amount of yarns (approx. 50-80 grams) which is not economically feasible for trading of yarn .So a larger package formulation from this cops are essential . For satisfaction of that need , a winding machine comes in vision of textile experts .This makes the use of the subsequent machines both easier and more economical .

In autoconer winding machine, generally 6 to 8 ring cops (or bobbins) in the magazine are wounded up into a bigger package called cone. From this number of cops, at first the yarns get unwound , then they get necessary winding tension by tension assembly of the machine and then finally they are wounded to the cone. Cleaning of yarns are also done in this machine by various separate cleaning units like EYC (Electronic Yarn Clearer) , Zenit+ , Uster Quantum, Oerlikon, LOEPFE, Uster Quantum-3 , Yarn Master etc. , used in autoconer machines of different manufacturers . Various modern features have come with the passage of technology like Automatic Splice Initiation, Web break detection, Automatic knife cut off, Automatic roll or package change etc. But the feeding of the ring cops in magazine are still done manually by workers.

But the operation of winding machine is not swift all the time. It has a number of modern and well optimized sensors and they frequently rejects ring cops to be wound in the cone. The main target of our project work is to find out the reason of the rings cops of being rejected by the autoconer winding machine by the analysis of rejected ring cops and also to find out some ways to avoid this unwanted situation .

7

1.1 Ring Cops

Ring cops are the final package got from the ring spinning machine which contains a small amount of yarn of a definite count . This cops contains 50-80 grams (1.5-3 ounces) yarns.

1.2 Rejected Ring Cops

The ring cops that are rejected by the autoconer winding machine to wound into larger cones due to various kinds of faults within the yarn are called rejected ring cops

1.3 Aim of this project

1. To know about rejected ring cops.

2. To know about the reasons of cops rejections in autoconer winding machine

3. To sort out some ways to slow down the rejection rates of cops.

8

Chapter 2 Literature Review

9

2.1 Winding

In spinning , winding is the process of creating large yarn packages called cone from some numbers of smaller yarn packages called ring cops in order to make the use of yarn in subsequent machineries both easier and economical .

2.2 Objects of winding

1. To prepare the bigger packages from ring cops

2. To remove spinning faults like neps, hairiness of yarn etc.

3. To wax the yarn as finishing process (if necessary)

4. To improve the quality of yarns by cleaning them

2.3 Types of winding

1. Spindle drive: Where the spindle upon which the package is placed is driven directly.

a. Constant speed winder

b. Variable speed winder

2. Friction drive: Where the spindle upon which the package is placed is free to rotate and the package is driven through friction by the contact of a driven drum.

2.4 Zones of winding

1. Unwinding zone

2. Tension and clearing zone

3. Winding zone

10

2.5 Working Principle of Autoconer Winding Machine

1. In the creeling zone, in all the winding positions of the machine, there is a magazine of ring cops which can carry 6 to 8 ring cops for winding

2. Yarn from a single cop goes tension and cleaning zone of winding machine through yarn guide which function is to provide sufficient tension to the yarn required for continuous winding of the yarn.

3. A yarn cleaning attachment is present in there in order to clean the yarn to maintain the optimum quality of yarn in the final package.

4. A sensor is also there called “Stopped motion feeler” to check if there is any breakage of yarn or absenteeism of yarn due to any reason like cops with no yarns

5. An splicing mechanism is also present there to untwist the ends of both previous and newcomer cop yarn and joining them by re twisting there ends.

6. Finally in winding zone , the yarns of all cops are wounded as a single yarn with the help of surface contact of a grooved cylinder.

Fig 2.1 : Working Principle of Autoconer Winding Machine

11

2.6 Autoconers used in factories along with specifications

Company Model No. Origin No of HeadsSchlafhorst Saurer Autoconer 388 Germany 60

SAVIO Machine TESSILI S.p.A

Polar M Italy 64

Sclafhorst Saurer Autoconer X5 Germany 60

Muratec 21C Germany 60

Fig 2.2 : Winding machine

12

2.7 Faults and Defects arising in winding which forms winding wastes

1. Formation of patches on the yarn.

2. Incorrect or variable winding speed

3. Too much knots in the yarn.

4. Variation of yarn tension.

5. Dirty or trashy packages

6. Incorrect shape of yarn package.

7. Excessive full bobbin.

8. Piecing up.

9. Over lapping.

10. Two end winding.

11. Mixing yarns of different linear density i.e. of different count.

12. Greasy and dirty yarns.

13. Poor yarn cleaning and snarling.

13

2.7 Reasons of formation of wastages on winding for faulty ring cops

1. Due to knots in the yarn on ring cops.

2. Remaining ends after tying off the yarns on the package

3. Slough off of yarns from the ring cops due to variation of yarn tension.

4. Remaining coils on the yarn package.

5. Dropped short ends while threading.

6. Greasy or dirty yarns in the ring cops.

7. Negligence of workers working in the winding department.

The amount of wastage depends upon the size of the spinning bobbin and breakage rate. With the increase of package size and reduced of breakage rate of yarn, wastage of winding is reduced.

14

Chapter 3 Experimental Work

15

3.1 Ring cops collection

Ring cops samples were collected from each of the autoconer winding machine . The collection of this cops are done on the basis of three points , one of them is either they are reject by the autoconer or not and the second one is if the yarn in ring spun cops are of spun from staple fibres , filaments or any special blends of natural or manmade fibres , third one is if they are any type of special yarns like core spun , SIRO , mélange or conventional 100% natural or manmade fibre yarn .

So the sample is collected on the basis of –

A. Either rejected or not rejected by the autoconer.B. Specification of the yarn present in ring cops in that sense of their origin of fibres like

100% natural like cotton , 100% manmade like polyester or if there is any blend of the two.

C. The type of yarn that means if they are normal ring spun yarn or they are ring spun but of special types of yarns.

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3.2 Procedure of the work

After collection of samples of ring cops , we went to the quality department of our factory to assess the type of fibres used in the yarns of different cops and also to sort out the causes that has given rejection of the cops in the autocoro . And some additional tests are also executed to find the causes of their rejections.

Test 1 : Uster AFIS test

To find out the neps present in the yarn and also to find out the average length of fibre and the maturity of fibres

Test 2 : DYNAJET test

To find out the weak points present in the yarn

Test 3 : Tectechno COVATEST

To find out the irregularity , hairiness and imperfection index (IPI) , unevenness U% , Coefficient if variation of mass (CVm%) of the yarns

Test 4 : Autostretch 5C test

To find out the CSP value of different yarns by finding out their individual lea strength

Test 5 : MAG-SITRA Ele Trash test

To find out the trash content present in our collected samples

Test 6 : MESDANLAB Autotwist test

To get the TPI and TPM value of samples

Test 7 : Yarn Count test

To recheck if there is no count variations in our sample

17

3.3 Causes of rejections

After getting all of our test results in hand , we went for a comparative analysis of the rejected cops with the accepted ones with the help of the personnel’s of quality department of the factory and get a numerous causes of rejections and they are described in the next article . We also tried to go to the backward of the production line to find out the cause that made the yarn in the ring cop that faulty so it was rejected by the autoconer winding machine .

3.4 Desprective discussion of the causes of rejection

3.4.1 Count Variation

At first three ring cops from the same magazine of the same autoconer tested and found that they were of two different counts that means two different linear density yarns. When two cops were wounded on the cone and autoconer started to fetch the yarn of the third cop , the sensors detected the variation of the counts and so it rejected the cop.

Causes

1. Negligence of workers in the winding section2. Negligence of workers of any previous sections like carding, drawing, simplex, ring

etc. sections that they mixed up different products which didn’t matched to the production plan and schedule.

Experimental Data Table : 3.1

Sample Type Count or Linear Density ResultCarded Yarn 30 Ne AcceptedCarded Yarn 30 Ne AcceptedCarded Yarn 32 Ne Rejected

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Remedies

1. Careful monitoring of all segments of production line from blowroom to final winding.

2. Recruitment of experienced and well trained workers in all the segments so that this type of unwanted incidents should never occour

3.4.2 Product Type Variation

Once again we tested three ring cops from collected from the same magazine and tested them for any product type variation , two of them were accepted by the machine and one was rejected . And we found two were carded yarn but the third one was combed yarn, but of the same counts.

Causes

1. Negligence of workers in the winding section2. Negligence of workers of any previous sections like carding, drawing, simplex, ring

etc. sections that they mixed up different products which didn’t matched to the production plan and schedule.

Experimental Data Table : 3.2

Count of the Sample Yarn Type Result26 Ne Carded Accepted26 Ne Carded Accepted26 Ne Combed Rejected

19

Remedies

1. Careful monitoring of all segments of production line from blowroom to final winding.

2. Recruitment of experienced and well trained workers in all the segments so that this type of unwanted incidents should never occour.

3.4.3 Low Cop Content

We took cops from the same magazine and measured there length using wrap reel and found that the rejected one has lower cop content than the accepted ones that means low amount of yarn in weight than the accepted ones. Causes

1. Under utilization of bobbin height in ring frame2. Lower number of coils /inch 3. Higher chase length in ring frame4. Cop bottom bracket properly not set in ring frame5. Improper selection of ratchet in ring frame6. Ratchet pawl pushing number of teeth's /movement in the ratchet wheel 7. Spinning empties wall thickness is high

Experimental Data

Table : 3.3

Sample Specifications Cop Content Result30 Ne Combed Hosiery 58 gm Accepted30 Ne Combed Hosiery 58 gm Accepted30 Ne Combed Hosiery 58 gm Accepted30 Ne Combed Hosiery 58 gm Accepted30 Ne Combed Hosiery 28.2 gm Rejected

20

30 Ne Combed

Hosiery

Accepted

30 Ne Combed

Hosiery

Accepted

30 Ne Combed

Hosiery

Accepted

30 Ne Combed

Hosiery

Accepted

30 Ne Combed

Hosiery

Rejecte

d0

20

40

60

Sample Vs Cop Content Graph

Samples

Cop

Cont

ent

in g

ram

s

Graph 3.1 : Sample Vs Cop Content

21

Fig 3.1 : Low cop content

Remedies 1. Optimum chase length, coil spacing and wall thickness of empty cops tube ensured in ring frame 2. Ratchet/pawl movement to be properly set 3. Free space of only 7.5mm to be maintained at the top and bottom of the cop 4. Free space only 0.75mm only to be maintained between full cops and the ring

3.4.4 Neps We tested some accepted and rejected cops by the autoconer winding machine and found that some cops are rejected due to presence of excessive neps onto the yarns . This test is done by Uster AFIS Tester. In general , neps are accepted to a certain limit , above that limit it is rejected ( exceptional is neppy yarn , where neps are given to yarn at a predetermined fashion )

Causes1. Accumulation of fly and fluff on the machine parts. 2. Poor carding3. Defective ring frame drafting and bad piecing 4. Improperly clothed top roller clearers.

Experimental Data

Table 3.4

Sample Specifications

Neps/km

+140%

Neps/km

+200%

Neps/km

+280%

Result

34 Ne Carded Woven

782.0 198.0 32.0 Accepted

34 Ne Carded Woven

786.8 199.2 33.02 Accepted

34 Ne Carded Woven

789.2 201.53 34.25 Accepted

34 Ne Carded Woven

852.69 254.78 71.25 Rejected

22

34 Ne Neppy 912.25 927.29 936.84 Accepted

34 Ne Card

ed W

oven Acce

pted

34 Ne Card

ed W

oven Acce

pted

34 Ne Card

ed W

oven Acce

pted

34 Ne Card

ed W

oven Reje

cted

34 Ne Nep

py Yarn

Accepted

0200400600800

1000

Sample Vs Neps/km Graph

Neps/km+140%

Neps/km+200%

Neps/km+280%

Sample

Nep

s/km

Graph 3.2 : Sample Vs Neps/km

Fig 3.2 : Neps in yarns

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Remedies1. Proper functioning of pneumaphil/roller clearers to be ensured. 2. Broken teeth gear wheel to be avoided and proper meshing to be ensured.3. Better fiber individualization at cards to be achieved.

3.4.5 Slub

Slub is an abnormally thick place or lump in yarn showing less twist at that place . We took some cops both rejecting and not rejecting by the machine and were tested in Uster AFIS Tester for result . In general this slubs are directly rejected for conventional ring yarns , unless they are special yarns where slubs are given intentionally. Causes

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1. Accumulation of fly and fluff on the machine parts. 2. Poor carding. 3. Defective ring frame drafting and bad piecing 4. Improperly clothed top roller clearers.

Experimental Data

Table 3.5


Slubs/km+400%

Slubs/km+460%

Slubs/km+520%

Result

40 Ne Carded Woven

2.59 2.87 3.12 Accepted

40 Ne Carded Woven

2.42 2.77 2.99 Accepted

40 Ne Carded Woven

2.36 2.69 2.87 Accepted

40 Ne Carded Woven

3.52 3.09 2.96 Rejected

40 Ne Carded Slub yarn

15.2 14.9 14.4 Accepted

25

40 Ne Card

ed W

oven Acce

pted

40 Ne Card

ed W

oven Acce

pted

40 Ne Card

ed W

oven Acce

pted

40 Ne Card

ed W

oven Reje

cted

40 Ne Card

ed Slu

b Accepted

0

4

8

12

16

Sample Vs Slubs/km Graph

Slubs/km +400%

Slubs/km +460%Slubs/km+520%

Sample

Slub

s/km

Graph 3.3 : Sample Vs Slubs/km

Fig 3.3 : Slubs in yarns

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Remedies:

1. Machine surfaces to be maintained clean. 2. Proper functioning of pnemafil /roller clearers to be ensured. 3. Broken teeth gear wheel to be avoided and proper meshing to be ensured. 4. Better fiber individualization at cards to be achieved. 5. Optimum top roller pressure &back zone 6. Setting at ring frame to be maintained.

3.4.6 Thick places in yarns

Thick places are the one of the imperfections of yarn that makes the yarn more thicker in some place according to its lengthwise which is not accepted by the autoconer winding machine . We took some samples and tested them in Textexchno COVATEST Tester to find out this variation .

Causes

1. Eccentric top and bottom rollers2. Insufficient pressure on top rollers 3. Worn and old aprons and improper apron spacing4. Improper meshing of gear wheels 5. Mixing of cottons varying widely in fibre lengths and use of immature cottons

Experimental Data Table 3.6


Thick/km+35%

Thick/km+50%

Thick/km+70%

Thick/km+100%

Result

60 Ne Carded Hosiery

450 32 2 0 Accepted


350 40 5 0 Accepted


822 621 379 128 Rejected

27

60 Ne Card

ed Hosie

ry Acce

pted

60 Ne Card

ed Hosie

ry Acce

pted

60 Ne Card

ed Hosie

ry Reje

cted

0

200400

600

800

Sample Vs Thick places/km Graph

Thick/km+35%

Thick/km+50%

Thick/km+70%

Thick/km+100%

Sample

Thic

k pl

aces

/km

Graph 3.4 : Sample Vs Thick places/km

Remedies

1. Eccentric top and bottom rollers to be avoided2. Top arm pressure checking schedules to be Maintained strictly 3. Wide variation in the properties of cottons used in the mixing to be avoided 4. Better fiber individualization at cards to be achieved. 5. Correct spacers to be utilized

3.4.7 Thin places in yarns

Thin places are another of the imperfections of yarn that makes the yarn more thinner in some place according to its lengthwise which is not accepted by the autoconer winding machine . We took some samples and tested them in Textexchno COVATEST Tester to find out this variation .

Causes

1. Eccentric top and bottom rollers2. Insufficient pressure on top rollers 3. Worn and old aprons and improper apron spacing4. Improper meshing of gear wheels

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5. Mixing of cottons varying widely in fibre lengths and use of immature cottons



Thin/km-30%

Thin/km-40%

Thin/km-50%

Thin/km-60%

Result


1435.0 110.0 5.0 5.0 Accepted

60 60 Ne Carded Hosiery

1245.0 78.0 2.0 2.0 Accepted


2512.0 498.0 412.0 376.0 Rejected

Table 3.8

Remedies

1. Eccentric top and bottom rollers to be avoided2. Top arm pressure checking schedules to be Maintained strictly 3. Wide variation in the properties of cottons used in the mixing to be avoided 4. Better fiber individualization at cards to be achieved5. Correct spacers to be utilized

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Thick/km+35%

Thick/km+50%

Thick/km+70%

Thick/km+100%

Result


450.0 32.0 2.0 0.0 Accepted

60 60 Ne Carded Hosi Hosiery

350.0 40.0 5.0 0.0 Accepted


850.0 672.0 612.0 516.0 Rejected

Fig 3.4 : Thick and Thin places in yarns

60 Ne Card

ed Hosie

ry Acce

pted

60 Ne Card

ed Hosie

ry Acce

pted

60 Ne Card

ed Hosie

ry Reje

cted

0500

10001500200025003000

Sample Vs Thin places/km GraphThin/km-30%

Thin/km-40%

Thin/km-50%

Thin/km-60%

Sample

Thin

pla

ces/

km

Graph 3.4 : Sample Vs Thin places/km

30

60 Ne Card

ed Hosie

ry Acce

pted

60 Ne Card

ed Hosie

ry Acce

pted

60 Ne Card

ed Hosie

ry Reje

cted

0

200

400

600

800

Sample Vs Thick places/km

Thick/km+35%

Thick/km+50%

Thick/km+70%

Thick/km+100%

Sample

Thic

k pl

aces

/km

Graph 3.5 : Sample Vs Thick places/km

3.4.8 Imperfections

Imperfections are known as the combinational term of all imperfections of yarns like thick places , thin places , neps , slubs etc . It is a number which is obtained by testing the sample yarns in Textechno COVATEST Tester. We took some samples in this test to find out the amount of imperfections in the rejected cops.

Causes

1. Insufficient pressure on top rollers 2. Defective rubber coating of cot rollers3. Poor carding and drafting efficiency4. Older and worn out aprons5. Inappropriate mixing of raw fibres 6. Miss positioning of spacer7. Bad waste collection system of the facility

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Experimental Data

Table 3.9

Sample Specification Imperfection Index (IPI) Result50 Ne Combed Woven 123.29 Accepted50 Ne Combed Woven 112.26 Accepted50 Ne Combed Woven 126.27 Accepted50 Ne Combed Woven 269.61 Rejected

50 Ne Combed Woven Accepted



50 Ne Combed Woven Rejected

0

50

100

150

200

250

300

Sample Vs IPI Graph

Sample

Impe

rfec

tion

Inde

x (IP

I)

Graph 3.5 : Sample Vs IPI Graph

32

Fig 3.5 : Imperfection Index (IPI) Spectogram

Remedies

1. Scheduled checking of top roller arm pressure2. Wide variation of fibre properties in mixing should be avoided3. Right apron and right spacer to be used4. Waste extraction and suction system should always keep efficient5. Higher efficiency to be targeted in carding and drafting

3.4.9 Unevenness in yarns

Yarn unevenness deals with the variation in yarn fineness. This is the property commonly measured as the variation of mass per unit length alongside the yarn . We tested some of the ring cops in Textechno COVATEST Tester for the assessment of Um% (Unevenness per meters) and found that some rejected cops have higher Um% Unevenness is expressed in two ways –

1. The Irregularity per meter Um%2. The Co efficient of variation per meter Cvm%

Causes

1. Variations in processed raw materials gives rise to higher unevenness of the end product

2. Variation in the spinning process like in correct drafting arrangement in drawing , simplex and ring frame

3. In correct setting of auto leveling unit in the finisher drawframe 4. Worn out machine parts in any production stage

33

Experimental data Table 3.10

Sample Specification

Irregularity perMeter (UVm%)

Co efficient ofVariation per Meter (CVm%)

Result


11.07 14.10 Accepted






22.24 27.93 Rejected

42 Ne Carded Hosiery Accepted



42 Ne Carded Hosiery Rejected

0

5

10

15

20

25

Sample Vs IPM (UVm%) Graph

Sample

IPM

(UVm

%)

Graph 3.6 : Sample Vs IPM (UVm%)

34





0

5

10

15

20

25

30

Sample Vs CVM (CVm%) Graph

Sample

CVm

%

Graph 3.7 : Sample Vs CVM (CVm%)

Remedies 1. Proper inspection of the raw materials so the variation in their unevenness

remains always low2. Scheduled observation of all process involved in spinning in drawing , simplex and

ring frame so that excessive variation can’t occour3. Setting of auto leveler in finisher drawframe should always try to keep as much

fixed as possible for a definite count and process4. Proper maintenance activities to check and rectify any mechanical damages

happened to any machine part like aprons , bottom and top rollers of drawframe , simplex and ring frame , broken gear teeths , displaced chains etc.

35

3.4.10 Some Miscellaneous Causes

A. Soft Yarn

Some yarns in cops are so much soft that they can’t bear the winding tension provided by autoconer ending machine and so they got torn out during winding and as a result the whole cop is rejected by the machine . This is the result of containing lesser twist in the yarn and this is assessed in DYNAJET Tester for the identification of weak point on the yarn and autostretch 5C Tester for checking if the TPI and TPM of required value is present in the yarn or not.

Causes

1. Slack tapes dirty jockey pulleys 2. Less twist in the yarn 3. Bad clearing at the traveler

Fig 3.6 : Soft Yarns

36

Remedies

1. Vibration of bobbins on the spindles to be avoided2. Proper yarn clearing to be ensured 3. Periodic replacement of worn rings and travellers to be effected

B. Yarn Hairiness

Yarn hairiness means the projecting or protreuding fibres that remains outside of the yarn’s surface and the give numerous problems or further processing . Excessive hairy fibres containing yarns gives problems onto winding and sometimes the cops containing hairy fibred yarn gets rejected by the autoconer winding machine . This hairness test is done in TextechnoCOVATEST Tester

Causes

1. Use of low matured cottons 2. Higher MIC vale of fibres that means coarser the fibres , higher the hairiness3. Uniformity Ratio (UR) less than 50% of the fibres4. In appropriate drafting and poor orientation in spinning triangle in ring

frame5. Rubbery surfaces damage , worn out machine parts etc


Sample Specification Hairiness Index H Result60 Ne Carded Hosiery 4.58 Accepted60 Ne Carded Hosiery 4.37 Accepted60 Ne Carded Hosiery 8.29 Rejected

37




0123456789

Sample Vs Hairiness Index (H) Graph

Sample

Hairi

ness

Inde

x (H

)

Graph 3.8 : Sample Vs Hairiness Index (H)

Fig 3.7 : Hairiness in yarns

Remedies

1. Higher removal of short fibres in carding2. Higher removal of neps in carding3. Higher cleaning and opening efficiency of blowroom machineries4. Better lubricating of machine points that can form static electricity during

running

38

C . Oil stained yarns Sometimes during lubrication or any tyoe of maintenance work or by any lickage in the lubrication system the yarn gets oil stained and when it goes to autoconer it gets rejected . We tested some ring cops and found that some of the cops that are rejected are oil stained

Causes1. Careless oil in the moving parts, over head pulleys etc 2. Piecing's made with oily or dirty fingers 3. Careless material handlings

Fig 3.8 : Oil stained yarns

Remedies

1. Appropriate material handling procedures to be followed2. Oilers to trained in proper method of lubrication 3. Clean containers to be utilized for material transportation

39

D . Crackers in yarn In some bobbins of polyester yarn , we found there very small snarl like places which

disappeared when we pulled the yarn with sufficient tension given by our hands but when the tension released , this effect was again visible . This are called crackers and only shown in thermoplastic man made fibres like nylon , polyester etc. These are also a cause for bobbin rejection on autoconer winding machine. They are also visible in cotton polyester blend yarns.

Causes

1. Mixing of cottons of widely differing staple length 2. Closer roller settings 3. Eccentric top and bottom rollers 4. Non optimum temperature and relative humidity in the spinning shed 5. Over spinning of cottons

Fig 3.9 : Crackers in yarn

40

Remedies

1. Optimum top roller pressure to be maintained2. Mixing of cottons varying widely in fibre length to be avoided 3. Use of optimum roller settings 4. Use of properly buffed rollers free from eccentricity to be ensured

D . Coca cola shaped bobbins

We found some type of different shapes of bobbins in the basket and coca cola shaped bobbin in one peculiar shaped bobbin and it is named coca cola bobbin due to its shape like a coca cola bottle . This shaped bobbins are directly rejected in autoconer

Causes

1. Uneven or variable speed of spindle2. It occurs during giving knots to the yarn in ring frame3. In appropriate building mechanism of ring frame by the cradle

Fig 3.10 Coca cola bobbin

41

Remedies

1. Always maintaining the speed of spindle at a constant rate2. Through monitoring of the workers not giving knots in wrong fashion3. Train the workers and allocate trained workers piecing section

D . Excessive Full bobbin

As the autocoro machine has an input panel and in this panel it is always given as input that how much amount of yarn it will be in a single cop . But when any excess cop or bobbin containg excess yarn is given into the magazine , after finishing its predetermined length , when autocoro wants a new cop but can’t take it cause previous one has still yarn in it , it rejects the previous excess full cop. Causes

1. Spindle speed variation that means higher speed than planned in production2. Carelessness of workers for collecting the full cops3. Improper piecing done by the workers

Fig 3.11 : Excessive full bobbin

42

Remedies

1. Always to keep the spindle speed at a constant

2. Workers should be made more careful and skilled

3. Piecing should be done by experienced workers

4. Excessive full bobbins should locate at the ring section quickly that it can’t create any problem in winding

E . Half fulled bobbins

This bobbins are not completely fulled that means the yarn length wounded on it in the ring frame is almost half to the length it should be wounded. Any partial winding on ring cop yarns are fallen into this type of bobbins and autoconer also rejects all of them because machine can’t complete any one cope into cone that it was comanded by the technicians. Causes

1. Improper piecing2. Carelessness of operators3. Variation of count onto the same lot

Fig 3.12 : Half fulled bobbin

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Remedies

1. Careful and perfect piecing of yarns2. Careful observations of machineries so that there should not be any

possibility of count variation3. Sometimes one spindle stops in a ring frame but all others run , so that one

remained stopped is surely half fulled bobbin . So it should be located as soon as possible because if it goes to winding , it will must be rejected by autoconer winding machine

3 .5 Some reports regarding winding

A. Characteristics : 60 Ne Short StapleTextechno COVATEST

Test No

Um%

CVm%3m

Index

Thin/km-40%

Thick/km+35%

Neps/km+200%

H

1 10.5 2.58 1.29 110 450 198 4.58

2 10.23 2.57 1.29 78 350 165 4.37

3 10.35 2.39 1.26 100 348 182 4.33

4 10.60 2.94 1.27 145 445 238 4.34

5 10.53 2.16 1.31 130 405 222 4.42

Avg. 10.44 2.53 1.29 113 400 201 4.41

CVb%

1.43 11.33 1.64 23 12 15 2.32

Q95%

0.19 0.36 0.03 32 61 37 0.13

44

B . Report : Autoconer Reject Ring Cops Study

Types of rejected ring cops

Shift A

Quantity

Pcs

Shift A

Quantity

%

Shift B

Quantity

Pcs

Shift B

Quantity

%

Shift C

Quantity

Pcs

Shift C

Quantity

%Coca Cola Bobbin

2 .2 13 1.29 5 .5

Over Piecing

25 2.48 32 3.17 24 2.38

Full Ring Cops

9 .89 16 1.59 31 3.08

Half Ring Cops

12 1.19 18 1.79 17 1.69

Total 48 4.76 79 7.84 77 7.64

3.5

45

Chapter 4 Conclusion

46

Conclusion

Winding has important influence and aspect on spinning because it is the last step where spinners can rectify their faults if there is any fault present in the previous stages. We tried our best to do our project work more accurately . We tried to visualize not only the conventional ring carded and ring combed yarn but also tried with some special yarns. We collected ring cops from various type of winding machines in the winding section of the production facility . We tried to keep in mind of collection of samples of same counts and of same processes. After collecting our samoles , we tested them in Uster AFIS , DYNAJET , Textechno COVATEST , wrap reel , MESDANLAB Tester , AUTOStretch 5C twist tester for various required values to complete our project work like co efficient of variation per meter CVm% , Hairiness index H% , imperfection index IPI , Neps and slubs content over length of yarn , irregularity per meter Um% , thick and thin places over various length of the samples etc. Not only quality parameters , but also we have seen various type of shaped bobbins like coca cola bobbin , half and excess full bobbins and found that they are directly rejected by the autoconer winding machine. We want to finish our project work by thanking Almighty Allah for giving us physical and mental strength , our respective teachers for helping us by providing many technical datas and careful monitoring and finally our both factory authorities for giving us all necessary helps and and friendly environment.

47

Chapter 5 Reference

48

Reference

1. Manual of Textile Technology (Vol 1-6) By W. Klein2. Application of Handbook of Uster AFIS PRO

The fibre processing system3. Handbook of Textile Fibres (Vol 1&2)

By J. Gordon Cook4. Principles of Textile Testing

By J.E. Booth5. Process Control in Spinning

By A.R.Grate6. Physical Properties of Textile Fibres

By W.E.Morton & J.W.S. Hearle7. Lectures of Dr. S. Subramanium

Associate Professor and Head of the IOCAnna University

8. Various slides from online www.slideshare.net9. Fundamentals of spun yarn technology

By Carl A. Lawrance10. The RIETER Manual of Spinning

RIETER Spinning Solutions11. Physical Testing of Textiles

By B. P. Saville12. Dictionary of Textiles

By B Y Luis Harmuth13. Website : www.uster.com14.Website : www.muratec.net15.Website : www.schlafhorst.de16. Website : www.saviotechnologies.com

49

http://www.saviotechnologies.com/

http://www.muratec.net/

http://www.uster.com/

http://www.slideshare.net/