Yarn hairiness controlled by modified yarn path in cotton ...nopr.niscair.res.in/bitstream/123456789/24691/1/IJFTR 30(3) 295-301... · The influence of yarn path on spinning triangle

Indian Journal of Fibre & Textile Research Vol. 30, September 2005, pp. 295-30 I

Yarn hairiness controlled by modified yarn path in cotton ring spinning

G Thilagavathi", G Gukanathan & 8 Munusamy

Department of Textile Technology, PSG College of Technology, Coimbatore 641 004. India

Received 25 May 2004; revised received and accepted 9 Novetnber 2004

The influence of yarn path on spinning triangle and, in turn, on yarn hairiness has been studied . The yarn s have been produced from cotton (40s Mali -juli and 60s MCU5) and 45s polyester/cotton (Recron/MCU5, 67 :33) by varying the yurn path in right and left diagonals by spinning with adjacent spindles and then tested for hairiness, strength, unevenness and breakage. The test results have been compared with the respective conventional straight path yarns. It is observed that there is a 50% reduction in hairiness in the left diagonal path with slight increase in strength. Right diagonal path shows deterioration in spinning eftic iency and no improvement in hairiness .

Keywords: Cotton, Ring sp inning, Spinning triangle, Yarn hairiness

IPC Code: Int. CI.7 001Hl3/00, D02J7/00, GOIN33/36

1 Introduction In manufacturing cotton yarns on widely used ring

spinning systems, at the exit from the rollers there is always a triangular bundle of fibres without twist, called spinning triangle. The spinning triangle and spinning angle affect fibre breakage and influence yarn structure. The long and narrow width spinning triangle implies a long weak point and hence causes more ends breakages. However, a resultant advantage of thi s small width triangle is that the edge fibres are better bound into the yarn, which gives a smoother (less hairy) yarn and hence less fly generation.

Stalder 1 has confirmed that when the spinning triangle gets smaller with increasing spinning tension, the hairiness is less. According to Klein2

, when the spinning triangle is short, the fibres from the edges must be strongly deflected to get bound into the yarn structure.

Yarn hairiness has a significant effect on yarn strength, spinning efficiency, yarn weaving and knitting performance, as well as on the properties of resultant fabrics made from such yarns, particularly their pilling tendency and uneven dye uptake3

• These protruding hair fibres make no contribution to yarn strength and elongation. They are also often

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unwelcome in downstream processes and amount to deficient utilization of raw material. The fly in spinning mills and in further processing steps is mainly due to the yarn hairiness. It is thus obvious that even ring-spun yarns are not yet ideal in terms of structure and quality. The quest for higher quality ring-spun yarns therefore continues, particularly in the area of hairiness reduction4

.

In the recent developments like compact spi nning by Rieter and Zinser, the systems reduce the spinning triangle to ensure less yarn hairiness. Wang 5 in his paper confirmed that the right diagonal yarn path produces yarn of lower hairiness in worsted spinning.

In the present work, the yarns have been spun from cotton (40s Mali-juli and 60s MCU5) and 45s polyester/cotton (Recron/MCU5, 67:33) by varying yarn path by spinning the yarn on both sides (left and right) of the conventional straight spinning. The hairiness level, imperfections, strength and elongation have been analyzed for both the yarns and compared with the conventional straight path yarn.

2 Materials and Methods

2.1 Materials 40s Mali-juli cotton, 45s polyester/cotton

(Recron/MCU5, 67:33) blend and 60s MCU5 cotton were used for the study. Fibre specifications and the spinning process parameters are shown in Tables 1 and 2 respectively.

296 INDIAN J. FIBRE TEXT. RES ., SEPTEMBER 2005

Table 1- Fibre specifications

Parameter 40s Mali-juli 45s Recron!MCU5 60s MCU5 (67:33)

2.5% span 28.6 29 .9 31.39 length, mm

Micronaire 3.7 3.53 3.71

Table 2- Spinning process parameters

Parameter 40s Mali-juli 45s PIC 60s MCU5

Machine make LR6 LRG5/l 015

Spindle speed, rpm 16700 15900 16600

TPI 25.58 23.14 29.59

Total draft 30.5 26.48 33 .77

Ring diameter, mm 38 38 38

Traveller no. 6/0 4/0 12/0

PIC- Polyester/cotton (Recron/MCU5 )

2.2 Methods The yarn is spun followi ng two yarn paths, namely

left diagonal path and right diagonal path, as shown in Figs l(a) and (b) Comparison has been made with respective normal straight path. With the left diagonal arrangement, the yarn emerging from a drafting unit is taken up by an adjacent bobbin to the left of the drafting unit, instead of the bobbin directly below it. For the right diagonal configuration, the yarn from a drafting unit is taken up by an adjacent bobbin to the right of the drafting unit, instead of the bobbin directly below it. The preliminary results of yarn quality confirmed that only left yarn diagonal path reduces hairiness than the conventional and right diagonal path. Hence, other studies have been carried out following only left diagonal and conventional path.

In ring spinning, the yarn is spun with Z-twist and hence the left diagonal arrangement gives better control of the fibres on the left- hand side of triangle. This is due to the shortening of spinning triangle at the left side which reduces the distance trave!Jed by the uncontrolled fibres to reach the convergence point as compared to conventional straight path . Therefore, with this left diagonal arrangement, the yarn hairiness is reduced. On the other hand, for the Z-twisted yarn the right diagonal arrangement actually increases yarn hairiness, because of the reduced control of fibres on the left - hand side of twist triangle.

Delivery roller

Lappet guide

~ RinR

~

So~ (a) (b)

Fig . I -Schematic diagram of ring spinning with diagonal yarn path [a- left diagonal , and b-right diagonal]

During modified path of spinning, the length of yarn between the front roller nip and the traveller is increased which leads to higher spinning tension, resulting in reduced width of spinning triangle. This may lead to increased end breakages. Hence, in this work the influence of left diagonal path on various yarn parameters, like hairiness, strength, imperfections and end breakages, has been studied.

2.3 Test Methods

2.3.1 Hairiness Testing The hairiness testing was carried out using Zweigle

G565 hairiness meter under standard conditions at a speed of 50 m/min and pre-tension of 5g. The number of hairs for all the classes was observed.

This Zweigle hairiness measurement (S3) gives the number of protruding fibres more than 3 mm in length in a measurement length of 100 m yarn. Zweigle hairiness testers give the absolute number of protruding fibres.

2.3.2 Tensile Strength and Elongation The tensile properties of yarns were tested on the

Premier Tensomaxx 7000 V2.3 at a speed of 5000 mm/min and a pre-tension of 0.5cN/tex.

2.3.3 Evenness Testing and Classification of Faults The Premier 7000 V3 .0.2 evenness tester was used

to study U% and imperfections at a speed of 400 m/min. The irregularity charts were analyzed for evenness.

2.3.4 Fabric Appearance Testing Fabrics were given to experts for appearance

evaluation. Based on the visual examination, the experts confirmed that there is a reduction in hairiness and imperfections of the fabrics.

THILAGAVATHI et al.: YARN HAIRINESS CONTROLLED BY YARN PATH IN COTTON RING SPINNING 297

3 Results and Discussion 3.1 Effect of Left Diagonal Path on Hairiness

The hairiness test results are shown in Table 3 and Fig. 2. It is observed that in case of long hairs (>3 mm length), there is 50% hairiness reduction in left diagonal yarn as compared to that in conventional straight path yarn. A reduction of 10-15% is observed in case of short hairs ( <2 mm) . The total number of hairs (both long and short) in case of left diagonal yarn is found to be half of that present in case of straight path ring yarn. A significant test has been conducted for straight and left diagonal path (LOP) yarn with respect to hairiness and it is found that the reduction in hairiness is significant at 95 % and 99% confidence level s.

This may be due to the reduction in distance between the front roller nip and the convergence point, resulting in reducing the traveling distance of less controlled fibres. The same trend is observed for the counts 40s Mali-juli and 45s PIC. The photomicrographs of yarn and fabric structures are shown in Figs 3 and 4.

3.2 Mechanism of Hairiness Control in LDP To explain the mechanism of hairiness control, the

following hypotheses may be proposed: (i) Spinning triangle becomes asymmetrical as shown in Figs 5 (a) and (b). Fibres aligned in the yarn path travel longer distance and those in the other side of the triangle travels shorter distance before reaching the convergence point.

(ii) There is differential tension acting on the fibres on the two sides of the spinning triangle.

(iii) For spinning a 'Z' twist yarn following LDP, the fibres in the shorter side (df) of the spinning triangle as shown in Fig. 5(b) are better controlled, leading to the reduction in hairiness, while the fibres on the ri ght hand side (de) of the spinning triangle are controlled by higher tension and pretwisting.

3.3 Yarn Strength and Elongation The tensile properties of straight and left diagon al

yarns are shown in Table 4 and Fig. 6. It can be observed from the table that the tenacity of left diagonal yarn is slightly higher than that of the corresponding straight path yarn, which is a

c§ 1400 0 ..._ 1200

'E 1ooo E (') 800 1\ '-" 600 ~

·;; 400 ..c: '0 200 ci z 0

II Straight path

0 Left diagonal path

40s Mali-Juli 45s PIC

Count

60s MCUS

Fig. 2- Comparison of hairiness between straight and left diagonal path yarn s

Table 3- Hairiness index values

Hairiness size mm

2

3

4

6

8

10

S3

40s Mali-juli

13946

1487

574

472

153

78

2

1279

No. of hairs

Straight path

45s PIC 60s MCU5

11793 13567

112 151

481 463

154 262

25 76

2 10

0

662 811

Left diagonal path

40s Mali-juli 45s PIC 60s MCU5

12308 6415 8986

1298 132 253

396 106 371

230 18 96

54 2 34

27 0 5

0 0

708 126 505

298 INDIAN J. FIBRE TEXT. RES .. SEPTEMBER 2005

significant difference since the same materials and process parameters were used in both the cases. The CV % of tenacity in left diagonal path is lower than that in straight path for all the yarns spun. Thus, it is clear that the left diagonal yarn is stronger and more uniform than the corresponding straight path yarn. This may be due to the better binding of fibres into the yarn structure because of the reduced triangle width and differenti al fibre tension in both sides of a

Fig. 3 - Strut:tun:s of straight and left diagonal path yarns Ia-- conventional straight path yarn structure for 40s Mali­juli. b- lef't diagona l path yarn structure for 40s Mali -ju li, c­conventional straigh t path yarn structure for 45s P/C, and d­lef't diagonal path yarn structure for 45s P/C]

Fig. 4 - Comparison of fa bri c struc tun.: I a - -;traig ht path yarn fabric structure, and b- left diago nal path ya rn fabric structure!

Len di•gonul puth Straight path

' .,., Pre·twisted ' fibres

(a)

-~~~

@ Right diUgonul puth

/Vurn

Len diagonal path Struight path H. 1ghl diugonul path

(b)

Fig. 5- (a) Ring spi nning wi th diagonal yarn path , and (b) Spinning triangles for different yarn pa•.hs in ring spinning

THILAGAVATHI et al.: YARN HAIRINESS CONTROLLED BY YARN PATH IN COTTON RING SPINN IN G 299

Table 4 - Tensile properti es

Parameter Straight path Left diagonal path

40s Mali -j uli 45s P/C 60s MCUS 40s Mali -j uli 45s PIC 60s MCUS

Break ing 268.76 301 .52 175.46 273.44 3 10.76 176.26 force . gf

(7 .09) (9.30) (9.62) (6 .94) (9 .44) (7 .52)

Break ing 5.09 8 .88 4.2 1 5.2 1 9.25 4.31 e longat ion, %

(5 59) (8.00) ( 10.88) (5 .69) (7 .07) (9.77)

Tenac ity, Rk m 18.2 1 22 .98 17.83 18.52 23.68 17.9 1

(7. 10) (9.30) (9.62) (6.94) (9.44) (7.52)

Break ing 364 08 7 16.77 208 .1 8 375.94 754.08 2 10. 11 work, kgfm

( I 0.87) ( 15.83) ( 18.24) (l 0.60) ( 14.24) ( 14.02)

Values in parentheses indi cate CV %

Table 5 - Yarn imperfec ti ons vahJes

Parameter Straight path Left diagonal path

40s Mali -juli 45s PIC 60s MCUS 40s Mali-j uli 45s PIC 60s MCUS

Um (%)

Mean 16.33 12.79 11.76 15.8 1 12.79 12. 13

so 0 .87 0.26 0.15 0.73 0.24 0.26

CVb 5.30 2.02 1.28 4.60 1.85 2.13

CVm(%)

Mean 20.88 16.30 15.02 20.2 1 16.30 I 5.46

so 1.1 4 0.33 0. 18 0.92 0.30 0.35

CVb 5.44 2 .00 1.23 4.57 1.86 2.24

Index(-)

Mean 1.98 1.73 1.1 5 1.9 1 1.74 I. IS

SD 0.10 0.04 0.0 I 0.09 0.03 0.03

CV b 5.30 2.07 1.1 6 4.55 1.93 2.22

Thin/km (-50%)

Mean 293 <17 13 229 44 30

so 120.33 2 1.8 1 4.3 1 106.65 19.39 11 .68

CVb 4 1.44 46.50 32.87 46.5 1 43.98 38.55

Thi ck/km (+50%)

Mean II 50 237 I SS 985 240 168

so 280 .1 2 39.95 20.39 203.3 1 33. 10 42.5 1

CV b 24.36 16.84 13. 18 20.65 13.79 25.25

Contd

300 I DIAN J. FIBRE TEXT. RES., SEPTEMBER 2005

Table 5 - Yarn imperfections values- Contd

Parameter Straight path Left diagonal path

40s Mali-juli 45s PIC 60s MCU5 40s Mali -juli 45s PIC 60s MCU5

Nepslk m (+200%)

Mean 942 445 289 938 439 329

SD 74.8 1 44.90 3 1.19 74.59 26.92 38.64

CVb 7.95 10.10 10.80 7.95 6. 13 11.75

SD - Stand ard deviati on, and CVb - Coeffici ent of variation between samples

" 24

21

~ 18

~ 15

.2 12 u ~ 9

~ 6

0 40s Mali-Juli 45s PIC

Count

Fig. 6 - Compari son of tenacity between strai ght and left diagonal path yarns

1700 1600 1500 1400 1300 1200

~ 1100

~1000 :: 900

~ 800 z 700

600 500 400 300 200 100

0 +---=='"--...-"

• Straight path

0 Left diagonal path

Objectionab le Short thick Long thi ck Long thin

fau lts Class ified faults

Fig. 7 - Compari son of classimate faults between straight and le ft d iago nal path 45s PIC yarns

spinning triangle . Almost all the fibres were embedded in the yarn structure and hence more num9er of fibres contribute to yarn strength .

3.4 Yarn Imperfections rn general, the numbers of thin places, thick places

and neps are lower for the left diagonal path yarns at

Table 6 - C lassimate faults fo r 45s PIC yarn

Parameter Straight path Left diagonal path

15 km 100 km 15 km 100 km

Objectionable 14 94 4 27 faults

Short thick 258 1720 252 1680

Long thick 23 154 5 34

Long thin 33 220 2 1 140

all the sensitivity levels (Table 5). But the qua lity gets deteriorated as the count becomes finer (60s). Thi s may be due to the increased tension because of higher speed. Fibre loss is also observed in the finer counts.

As compared to respecti ve straight path yarns, 21.8% reduction in case of thin places, 14.3 % in thi ck places and 42% in neps have been observed for left diagonal path yarn. The same trend is observed fo r 45s PIC yarn.

3.5 Classimate Faults Yarn faults were classified us ing Classidata 7000

for 45s PIC. It is observed from the Table 6 and Fig. 7 that there is a significant reduction in the case of objectionable faults (71.4%), short thick (32%), long thick (26%) and long thin (36.36%) for le ft di agonal path yarn in comparison with strai ght path yarn .

4 Conclusions The left diagonal path yarn leads to reduced yarn

hairiness. This is due to the fact that the le ft diagonal arrangement gives better control of fibres on left -hand side of the triangle. The study confirms that the 50% of hairiness reduction is observed in the case of left diagonal path yarn for coarser counts such as 40s Mali-juli and 45s PIC yarns. Thi s definite ly enhances

THILAGAVATHL eta/.: YARN 1-IAIRLNESS CONTROLLED BY YARN PATH IN COTTON RING SPINNING 301

the yarn quality and spinning performance with the reduction in yarn imperfections .

Acknowledgement The authors are thankful to M/s Lakshmi Mills

Company Ltd, Coimbatore, for providing facilities for spinning the yarn and weaving of fabrics. The authors are also grateful to Mr T L Yiswanathan, General Manager, Mr Christopher Karunakaran, Weaving Manager, and Mr Sridhar, Quality Control In-charge, Lakshmi Mills Company Ltd, Coimbatore, for their suggestions, technical ideas and support.

References Stalder H, New spin ning process comforspin. Melliand In !, (6) (2000) 26.

2 Klein W, Spinning geometry and its signiticance. lnt Te.rl Bull, Fabric Forming, (3) (1993) 22-26.

3 Barella A, Yarn hairiness, Text Prog. 13 (3) (1983) .

4 Wang X & Miao M , Reducing yarn hai riness with an air-je t attachment during winding, Text Res J. 67 (7) ( I 997) 48 I-485.

5 Wang X. Reducing yarn hairiness with a moditied yarn path in worsted ring spin ning, Text Res J, 73 (4) (2003) 327.