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STUDY OF THE EFFECT OF INCLINATION OF SPINNING TRIANGLE ON THEPROPERTIES OF RING AND COMPACT SPUN YARNS

Magdi El Messiry,

Faculty of Engineering, Alexandria University, Egypt

[email protected]

Abstract

In the last decade, the introduction of compact spinning is considered as a breakthrough in thespinning technology due to the improvement of the yarn quality. All the systems for theproduction of compact spun yarns consist of a modification of the drafting system on the ring

spinning machine, so that the spinning triangle dimension decreases. In this work, the reductionof the spinning triangle is obtained by suggesting of changing the path of the yarn, thus the anglebetween the front roller nip line and the yarn becomes smaller. This method was tried on bothring and compact spinning machines. The properties of the yarns processed on the differentsystems are investigated. It was found that inclined formation of the spinning triangle results inproduction of yarns of superior properties than the conventional ring or compact spun yarns,specially the yarn tenacity, 10% higher, as well as the increase in the elongation by 5%. Thehairiness was reduced significantly. This will give better results with short staple cotton at noadditional cost.

Keywords: ring spinning, compact spinning, yarn tenacity, yarn hairiness

Introduction

In conventional spinning a spinning triangle is formed immediately after the draftingmechanism in the ring spinning machine. While in compact spinning, the spinning triangleassociated with conventional ring spinning is eliminated by pneumatic compaction. This happensby several means such as suction and compaction on a perforated revolving apron or drum infront zone of the drafting system [1-2] [14]. The introduction of a fourth nip point downstream ofthe exit drafting system and the use of the aerodynamic condensing of the fibers through suctionresults in narrower spinning zone with individual fibers more effectively bound into the yarnassembly. These changes the properties of compact yarn compared with that of conventional

yarn . The properties of compact spinning were thoroughly investigated by a several researchers[3-16]. The results of their studies indicated that compact spun yarn strength is higher by about15% and elongation at break by about 20%. Furthermore, the yarn hairiness becomes 70% less,and the coefficient of variation of the yarn lowered by 15% than that for the equivalent ring spunyarn. Compact spun yarns had better abrasion resistance. These advantages can be reflected ondownstream processing. Muhammad [17] indicates that fabric properties in terms of breakingstrength, breaking elongation and tear strength are also better with the use of compact spun yarn.Clinging tendency of compact yarn shows considerably fewer and less pronounced clinging
mailto:[email protected]:[email protected]:[email protected]


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phenomena. Lower clinging tendency of the yarn results in the improvement of the warp yarnseparation. This reduces the cost of sizing and subsequent desizing, and at the same time,resulting in lesser environmental pollution. Despite the lower degree of sizing, thread break ratesare lower, which significantly improves loom efficiency, and fabric appearance. In compact yarnless twist is possible without any loss of the strength. This results in lower manufacturing cost

and softer twisted yarns. The improvement in the strength of compact yarns is claimed to be dueto the increase of the rate of fiber migration as well as the amplitude of migration [6]. Therecovery parameters of compact yarn are superior to the corresponding ring yarns. Theimmediate elastic recovery is increased, whereas delayed recovery and permanent set aredecreased for compact yarns [13]. In spite of the superior properties of compact spinningsystems, the cost of the production yarns is still higher than in ring spinning. Further trials areneeded to get the advantage of the compact yarns at less cost through new inventions to reducethe spinning triangle.

In this work we suggest the reduction of the spinning triangle by the inclining of the yarnpath to nip line of the front roller on the ring spinning. That will reduce the size of the spinning

triangle, and partially compact the produced yarn because the point of the twist insertion will bemoved further towards the nip line. This method we entitled semi-compact spinning. Theprinciple of yarn formation with the inclined spinning triangle was examined for both ring andcompact spinning and its effect on yarn properties.


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2. Material and methods Experimental2.1 Yarn samples production

The first objective of the experimental work is to prove the possibility for the production ofsemi-compact spun yarns directly on the conventional spinning machine. In order to processsemi-compact yarn, the yarns at any position on the conventional ring spinning machine arethreaded through a guide, so that their paths are inclined to the nip line of the front roller. Thisgives the yarn angle of inclination to the original path by 30 degrees. Several yarns samples wereproduced on ring, compact, and semi-compact spinning machines. The produced yarns are spunwith noil percentage 16 %.several yarn count are spun with counts ranged between Ne 30/1 and

Ne 94/1and twist factor 3400 ( tpm tex )2.2 raw materialsThe Egyptian cottons G70 are used in this study with the following properties G70 (upper halfmean 34.7mm, fiber micronair 3.81, tenacity 46.4cN/tex),

3. Results and discussion

On the conventional ring spinning machine, the fibers coming from the front roller of thedrafting system will be forced to pass through the spinning triangle to the point of the twistinsertion. The spinning tension acting on the yarn will cause an unequal loading on the fibers inthe spinning triangle which in its turn will cause the fiber migration [9].In the case of compact spinning, special attachment is provided to reduce the spinning trianglewhich leads to the reduction of the yarn hairiness and produces highly compacted yarn structure.Oxenham [6] shows that in the ring spinning the thin ribbon like fiber bundle is transformed intoa roughly circular shape by twist insertion, fibers at the edges of the bundle are forced with thetension, whereas fibers in the middle are subjected to compression. To release the s tress, the edgefibers try to short their path and migrate between yarn layers leaving their perfect helical path. Inthe case of compact spinning, the same mechanism is presented in compact yarns, but a majordifference is that everything is happening in a very short distance. However, the rate of change offiber radial position is higher in compact spinning [6].Moreover, the value of the strain of the fibers in spinning triangle will depend on their position

at the base of the triangle [9] so that the minimum strain will be for the fibers at the middle oftriangle base, which is the core fiber, and maximum will be for the edge fibers. The value of thestrain of the fibers will be distributed according to the following equation:Ei = E c /Cos ( i)Where:Ei - strain of the fiber at the angle i Ec - strain of the fiber at the center of the yarnFrom this equation, it is clear that the fibers located at higher value of i will have a highertension which will accelerate fiber migration. In compact spinning, the strain of the edge fibers isincreased due to the change of the spinning triangle size which leads to the increase of themaximum angle of the inclination. That increases the migration rate and causes the increase ofcompact yarn tenacity.


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The method (semi-compact spinning) for the reduction of the spinning triangle dimensionssuggests the inclining the yarn path towards the nip line of the front roller which allows the twistto move upward towards the nip line reducing the size of the spinning triangle, thus the fiberstrain distribution in the spinning triangle will be completely different than that in compactspinning. Figure (1) shows the shape of the expected spinning triangle for three spinning systems,

which indicates that for the semi-compact spinning the minimum strain, will be for the fibers atthe left edge of the spinning triangle, while the fibers at the core of the yarn are subjected to thehigher strain.The strain of the fibers in the case of the semi-compact spinning can be increased through theincrease in the angle of inclination of the yarn path. Migration pattern of the fibers is expected tobe different from that of the ring and compact spun yarns. The inclination of the path of the yarnmay be either to the right or to the left.

Figure (1) spinning triangle for ring spinning, compact spinning and semi-compact spinning

In order to compare the yarn properties, three yarns are spun on three spinning systems intocounts of Ne 50/1, 56/1, 94/1. The results of the testing of the yarns produced on the threespinning systems are analyzed. Figures (2), (3), (4), (5), (6), (7), show the comparison between

the properties of the yarns spun by the different spinning principles.


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0

510

15

20

25

30

50/1 56/1 94/1

Y a r n T e n a c i t y

, c N

/ t e x

Yarn Count Ne

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Semi-Compact

Compact

Figure (2) yarn tenacity

4.24.44.64.8

55.25.45.6

50/1 54/1 94/1

Y a r n E

l o n g a t i o n

, %

Yarn Count Ne

Ring

Semi-Compact

Compact

Figure (3) yarn elongation%

0

5

10

15

20

50/1 54/1 94/1

Y a r n U n e v e n n e s C V %

Yarn Count NeFig.(4)

Ring

Semi-compact

Compact

Figure (4) yarn unevenness

0

50

100

150

200

50/1 54/1 94/1

T h i c

k P l a c e s

/ K m

Yarn Count Ne

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Semi-Compact

Compact

Figure (5) yarn thick places/km

020406080

100120

140

50/1 54/1 94/1

N e p s / K m

Yarn Count Ne

Ring

Semi-C0mpact

Compact

Figure (6) yarn neps/km

0

50

100

I m p e r

f f e c t i o n

/ K m

Thin

Thick

Neps

Figure (7) yarn imperfection/km


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Fig. (8) shows a comparison between the yarn imperfections for the three spinning systems,which indicates that the both ring and semi-compact yarns have the same yarn imperfectionswhile compact yarns have less.

0

5

10

15

20

25 CVm%

Tenacity RKM

Elongation%

Hairiness

Figure (8) comparison between the average values of the different properties of the yarns spunby the three spinning systems.

a comparison between the average values of the different properties of the yarns spun by the

three spinning systems are illustrated in Figure (8).The comparison between the average results of the three systems indicates that:

-The yarn unevenness CVm% is the same for ring and the equivalent semi-compact yarn.-The tenacity of the semi-compact spun yarns is higher by 10% than that of the equivalentring spun yarns. While the tenacity of the compact spun yarns is superior to the semi-compact spun yarns only by 4.3%.-The yarn hairiness of the ring and semi-compact spun yarns is the same, but the compactspun yarns have less hairiness by 50%.- The elongation of the semi-compact spun yarns is higher by 5% compared to the ringspun yarns.

From the above results it is clear that the properties of the semi-compact yarns are better than

that of the ring spinning yarns, especially in the yarn tenacity and elongation.The increase of the semi-compact yarn tenacity indicates that there is a change of the migrationbehavior of the fibers due to the change of the strain distribution on the fibers at the spinningtriangle as it was explained above. The hairiness was not reduced due to the increase of therubbing angle on the yarn surface at the yarn guide. Further investigation is needed to study thiseffect in order to improve the yarn hairiness of the semi-compact yarns.This indicates that the quality of the yarns spun by the three different systems can be graded asCompact spun yarns, Semi-Compact, and then Ring spun yarns.


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The second part of this study is to confirm the above results which indicate that the semi-compact yarns possessed improved yarn tenacity than that of the conventional ring spun yarns.Different yarns of counts ranged between Ne 30/1 and Ne 94/1 are spun by the ring and semi-compact spinning systems.Figures (9) give the comparison of the different yarn properties.

05

1015202530

30/1 50/1 60/1 94/1

T e n a c i t y

, c N

/ t e x

Yarn Count Ne

Ring

Semi-Compact

01234567

30/1 50/1 60/1 94/1

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%

yarn count Ne

Ring

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01234567

30/136/150/156/160/180/194/1

Y a r n H a i r i n e s s

Yarn Count Ne

Ring

Semi-Compact

0

5

10

15

20

25

Ring Semi-Compact

CVm%

Tenacity RKM

Elongation%

Hairiness

Figure (9) comparison between yarn properties of ring and semi-compact yarns

From the analysis of the results shown in Fig (9) it can be concluded that the averageyarn tenacity of the semi-compact yarns is higher by 10 % than the equivalent ring spunyarns, while their elongation is higher by 5 %. The other properties are the same due tothe fact that the semi-compact yarns are spun on the same ring machine from the sameroving.

Part IITo apply the same principal of the yarn formation with the inclined triangle on compactspinning, several yarns are produced of different counts. In order to process modifiedcompact yarn, the yarns at any position on the conventional compact spinning machineare threaded through yarn guide to the next spindle to the right or to the left spindle, sothat their paths are inclined to the nip line of the front roller. For the comparison, thesame yarn counts were produced on the conventional ring and compact spinningmachines, as well as modified compact spinning machine on both positions. Figures (10-


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15) show the properties of yarns processed on three spinning systems and the relativeratio of the yarn properties spun on compact and mod-compact to that of ring spinningyarn.From the analysis of the results it was found that the second position of the yarnformation gives better yarn quality in the case of modified compact spinning.

Also the analysis of the properties of the yarns produced on the ring, compact, andmodified compact show that the main improvements in the case of the modified compactspun yarns are the yarn tenacity and yarn hairiness index, the ratio of the modifiedcompact to ring yarn tenacity may reach 1.23, while the yarn hairiness in the case ofmodified compact spinning gives better values than ring or ordinary compact yarnsespecially for the fine counts. The ratio of modified compact spun yarn hairiness indexmay reach 0.55 than that of the ring spun yarns. The other properties are the same as thatof compact spun yarns.This leads to the recommendation that in the case of short staple the modified compactspinning can give better yarn tenacity and lower yarn hairiness.

Figure (10) comparison of the yarn tenacity of the different systems for different yarncounts


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Figure (13) Comparison of the relative yarn coefficient of variation ratio of the differentsystems relative to ring spinning

Figure (14) comparison of the yarn hairiness index of the different systems for differentyarn counts


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Figure (15) Comparison of the relative yarn hairiness ratio of the different systemsrelative to ring spinning

The above figures analysis indicates the improvements of the compact yarn spun thesame compact spinning with inclined triangle (mod-compact). Which indicates that thissystem gives improvement in the yarn tenacity and elongation without affecting the otheryarn properties especially in the case of fine counts?

ConclusionFrom the results, it can be concluded that,

Generally, the formation of the yarn with the inclined spinning triangle givesbetter yarn properties. The improvement of the yarn quality differs when usingring spinning or compact spinning. This is due to the fact that the compactspinning gives more condensed structure so that the formation of the yarn on theinclined plan will be of less effect than in the case of ring spinning.

Semi-compact yarns show the increase in tenacity and elongation, but the samehairiness, yarn imperfection and yarn evenness as the ring yarns.

. Modified compact yarns can be processed on the conventional ring spinningmachines for all ranges of yarns count. Modified compact yarns show animprovement in the tenacity and yarn hairiness index than ring and compact yarns,and are recommended for processing of short staple cottons.


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References1. Stadler, H., New Spinning Process Comfor Spin, Melliand International 6, No 1 -22,

2000. 2. Thum, R., Suessen, Elite Spinning System for Long and Short Staple Fibre, Textile World

150, No 4, 38, 2000

3. Kampen, W., Advantages of Condensed Spinning, Milliand International 6, 98 -100(2000).4. Meyer, U., Compact Yarns: Innovation as a Sector Driving Force. MilliardInternational 6, 2, (2000).5. Stadler, H., Compact Spinning A new Generation of Ring Spun Yarns. MelliandTextilberichtee 76(3), E29-E31 (1995).6. Basal, g., and Oxenham, W., Comparison of Properties and Structure of Compact andConventional Spun Yarns, Textile Res. J. 76(7), 567 -575.7. Klein, W., A Practical Guide to Ring Spinning, The Textile Institute Manual ofTextile Technology, MFP Design & Print, Manchester, UK, 1987.8. El Messiry M., New Attachment for Compact Spinning, 1 st International TextileConference NRC, 2004.9. Krause, H., Soliman, H., Investigation of the Strength of the Spinning Triangle inRing Spinning, Melliand Textilberichte 72 (1991), p. 499. 10. Cheng, K., Yu, C.: A Study of Compact Spun Yarns, Textile Res. J. 73 (2003).11. Artz, P.: The Special Structure of Compact Yarns-Advantages in DownstreamProcessing, ITB Yarn and Fabric Forming (1997) 2, 41-48.12. Behera, B., Hari, P., Ghosh, S.: Weavability of compact Yarn, Melliand International,9 (2003) 311-314.13. Goyal, A., etal, Comparative Study of Ring and Compact Spun Yarns,Melliand International 2 (2007).

14. Goktepa, etal, A Comparison of Compact Yarn Properties Produced on Differentsystems, Textile Res. J. 76 (3), p. 226. 15. Krifa, Ethridge, Compact Spinning Effect of Cotton Quality Interaction with FiberCharacteristics, Textile Res. J., 76 (5), p. 388.16. Krifa.m, Ethridge.D, "Compact Ring Yarn: An Examination of Some ProductionIssues, Textile topics volume 2003 -2 .17. Muhammad Ahmad, Future belongs to compact spinning, August ,the Indian TextileJournal, 2009. 18 . Krifa, Mourad; Ethridge, M Dean, Compact Spinning Effect on Cotton Yarn Quality:Interactions with Fiber Characteristics, Textile Research Journal May 2006 vol. 76 no. 5,pp. 388-399.
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