5 International Journal of Fiber and Textile Research 2012; 2(2): 5-11

ISSN 2277-7156

Original Article

Role of spinning process variables on dynamic process of hair

formation in ring spinning

Vaibhav K. Dhange

Department of Textiles, DKTE Society’s Textile & Engineering Institute,

‘Rajwada’, Ichalkaranji, Dist. Kolhapur, (M.S), India (Received 2

Cell: 0091 9604761959, E-mail: profvkd@gmail.com

Received 04 May 2012; accepted 31 May 2012

Abstract

Yarn hairiness originates in the spinning triangle where individual or bundle of fibres are twisted and consolidated. It was supposed that, in a Z-twist yarn fibres in the left hand fringe were more responsible for the formation of hairs. In this study an

attempt was made to verify different theories of hair formation and to study the effect of various processing parameters on the

contribution of left hand fringe and right hand fringe of the spinning triangle to the hair length distribution. With the aid of

CCD camera, it was planned to capture continuous photographs of spinning triangle to demonstrate the formation of different

types of yarn hairiness. It was also planned to study the effect of parameters like traveller, roving hank and TM on the

contribution of right hand fringe and left hand fringe of fibres in spinning triangle to the formation of the yarn hairiness and

hair length distribution.

© 2011 Universal Research Publications. All rights reserved

Key words: hairiness, ring spinning triangle, traveller, roving hank, twist multiplier, CCD camera.

1. Introduction

A lot of research work has been done to find out mechanism

of hairiness formation on ring spinning machine, and

different factors affecting yarn hairiness and various means to

reduce it. Morton and Yen[1] pointed out that, in practice

delivery speed of the front roller is same for all fibres. This

means that during twisting, the fibres of a yarn must be in

varying states of tension depending upon the positions they

occupy. The fibres lying on the surface will be at higher

tension than those near the core as they have to follow a

longer path. When a trailing end emerges from the nip of the

front roller, there is almost no tension in the fibre to collect it into the yarn. If at that instant a short fibre happens to be one

of those following longer paths among the outer zones, it will

cease to be an effective competitor for a core position.

Therefore, it is easily expelled to the surface and appears as a

projecting fibre. Morton[2] pointed out that, in a Z - twist

yarn; fibres in the right hand fringe of the ribbon can fold

over freely towards the left at the point of yarn formation. But

fibres in the left hand fringe are not similarly free to fold –

under towards the right because of obstruction by the top

breast of the bottom drafting roller; thus they are likely to be

concentrated in the outer zone of the yarn. As per Barella[3]

yarn hairiness is produced by protruding fibres, wild fibres

and loops.

Stalder[4] showed schematic view of yarn formation

zone where fibres are delivered by the drafting unit over

width W, which depends upon yarn count, twist level in

roving and total draft. Downstream of the nip-line, between

the delivery rollers, the actual yarn formation takes place.

The spinning triangle gathers the incoming fibres from the drafting unit and incorporates them into the yarn structure.

Width of spinning triangle, w, is inversely proportional to the

spinning tension. Under practical condition width W is larger

than width w. Therefore, spinning triangle cannot catch all

incoming fibres. The more is the difference between W & w,

more are the edge fibres getting escaped of twisting action

and lost or attached to the already twisted yarn core in a

disordered configuration.

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Universal Research Publications. All rights reserved

6 International Journal of Fiber and Textile Research 2012; 2(2): 5-11

Klein[5] pointed out that, the twist determines one of

the dimensions of the spinning triangle, namely the length L.

He stated that high yarn twist results in a short spinning

triangle. For a given exit width of fibre strand, W, the length

of spinning triangle determines in turn its width w, (which is

always smaller than W). And depending on the twisting height, with short triangle, many edge fibres are not tied in

owing to the high deflection angle required. He also stated

that not only the twist in yarn but machine design also affects

the length of spinning triangle, through the wrap angle of the

fibre strand on the front roller. The greater the wrap angle,

longer is the spinning triangle formed. This deflection leads

the spinning triangle additional guidance, and above all

prevents a very abrupt bending - off of the edge fibres

emerging from the nip. He concluded that it is primarily the

angles that matters much rather than the length of triangle.

This study aims to observe formation of different

types of hairs with a series of photographs and to study effect of parameters like traveller, roving hank and twist multiplier

(henceforth TM) on the contribution of right hand fringe

(henceforth RHS) and left hand fringe (henceforth LHS) of

fibres in spinning triangle to the formation of the yarn

hairiness and hair length distribution.

From images obtained from CCD camera, it is clear

that for a Z- twist yarn, twist flows in the right hand side of

the fringe, but not all fibres at the right hand side are

accumulated. The contribution of left hand side of the fringe is

more for formation of loops and hairs.

2. Materials and methods

2.1. Experimental Set up to observe hair formation

For this project an AVC 571 Digital Colour CCD camera was

used to capture images of spinning triangle. The camera was

attached to a microscope with magnification of 10 X; and the

whole assembly was mounted 7cms away from the nip of the

drafting rollers. An image grabbing card was used to record

images continuously on hard disk of computer. With the help

of VCD cutter software, images were examined frame by

frame within 1/25 second.

2.2. Planning of experiment Experiments were planned according to the orthogonal array

advocated by Taguchi. The application of L-9 orthogonal

array includes use of 3 factors at 3 levels. The process

variables (treatments) for three levels of factors of orthogonal

array are roving hank, twist multiplier and traveller (Table 1

& 2).

2.3. Spinning

To facilitate observation of fibres coming from 2 zones,

namely right hand zone and left hand zone, two rovings of

different colours, one white and other red, were used. Both rovings were drawn from the same mixing. The yarn spun

was of 16s Ne. Yarns were spun under 9 runs (Table 2) on a

G5/1 ring frame.

2.4. Testing of yarn hairiness

Hair Length Distribution can be found out by using Zweigle

G565 hairiness tester, but it is not possible to count fibres

having different colors. Therefore, analysis of hairiness was done manually using microscope with magnification of 10 X .

Two bobbins were tested per run for hair length distribution

and average was calculated. 52 readings (each of 5cms of

yarn) were taken per bobbin. The contribution of right hand

fringe and left hand fringe to the hair length distribution at

the start of the doff and at the end of the doff were also

studied. The fact that hairs of length 1 to 2 mm are essential

due to the fact that air can cling to enormous surface area

created by these hairs. Air is an excellent insulator and

therefore helps in increasing the thermal insulation of fabric.

It also provides a soft feel to knitted fabric. Therefore, in this

study hairs and loops longer than 2 mm were measured.

3. Results and discussion

3.1. Formation of yarn hairiness

3.1.1. Concept of pre-twist

In a Z - twist yarn, twist propagates from the right of the fibre

fringe towards the left side of spinning triangle. Pre-twisting

in the right hand fringe causes fibres in the RHS of a spinning

triangle tend to accumulate (Fig.1). On the other hand,

several fibres in the left hand fringe are apart from the main

fibre fringe and are not yet twisted. This may be because the fibres in the left hand fringe are not free to fold under to the

right due to the obstruction by the bottom rollers.

It is a wrong assumption that all the fibres in the

right hand fringe are under good control due to twist. Not all

the fibres are pre-twisted. In spinning triangle fibres at the

middle of the fringe are the first to take twist. Some edge

fibres in the right hand fringe are not accumulated by the pre-

twist. Therefore, it is expected that their behaviour will be

similar to that of the edge fibres at the LHS.

Fig.1. Concept of pre-twist

7 International Journal of Fiber and Textile Research 2012; 2(2): 5-11

Fig.2. Fibre conditions in spinning triangle

3.1.2. Fibre conditions in spinning triangle

A fibre can occupy four different conditions in the spinning

triangle (Fig. 2). In first condition leading end of the fibre is

attached to the convergence point. In second condition

leading end of the fibre is not grasped by the convergence

point and it has no tension. In third condition trailing end of

the fibre is under control due to the friction with

neighbouring fibres. In fourth condition trailing end of the fibre is free and has no tension.

3.1.3. Formation of trailing hairs

When conditions 1 and 4 are satisfied, trailing hair is formed.

With the rotation of the yarn, the leading end of the fibre is

either grasped by the convergence point of triangle or

wrapped around the yarn, as soon as the trailing end leaves

the nip of the front roller, it will release the tension and

protrude out of the triangular plane. Sometimes, buckling of

the fibre at the right hand side occurs. Such type of buckling

occurs when leading part of fibre is wrapped around the yarn and due to the rotation of the yarn, fibre is under tension, and

a sudden release of the tail of the fibre results in an abrupt

loss in fibre tension and snap back of fibre occurs.

Yarn and hence triangle, changes its position every

now and then. When yarn moves towards one side, it

manages to catch edge fibres from that side, but fibres

coming from other side have to follow a long path, and thus

they will produce long hairs.

3.1.4. Formation of leading hairs

When conditions 2 and 3 are satisfied, leading hair is formed.

When a fibre emerges from the drafting zone, it has to cross the distance from the front roller nip to the convergence

point. Leading end, especially at the extreme of triangle

needs enough radial force from the surrounding fibres.

Otherwise, it tends to move straight ahead and miss the

convergence point. But, the rotating yarn can manage to catch

remaining part of such escaping fibres and wrap most of them

around itself, leaving leading end protruded free (Fig. 2).

3.1.5. Formation of loops

The configuration of fibre in the ribbon and slackness of fibre

in the spinning triangle may be responsible for formation of loops. When fibre is slack and conditions 1 and 3 are

satisfied, a loop is formed. First leading end of the fibre is

grasped by the convergence point or get wrapped around the

yarn. When tail of the fibre emerges from the nip of the front

drafting rollers, it is caught by the convergence point or yarn

before it protrudes out of the triangular plane. Thus both ends

of a fibre are grasped, leaving middle part of fibre slack. This

leads to the formation of loop.

Many times poor alignment of fibres is also

responsible for the formation of the loop. In case of looped or

hooked fibre, U shaped part comes out of the front roller nip first. Since the two ends of the fibre are twisted into the yarn,

looped part stood proud of the yarn. Many times snap-back of

the fibre also causes formation of loops if free end is caught

by yarn.

3.2. Analysis of yarn hairiness

3.2.1. Contribution of LHS and RHS to hairs and loops

For most of the runs, contribution of RHS to the protruding

hairs and loops is above 40% (Table 3 & 4). Contribution of

RHS for the short and medium hairs is just at par with that of

LHS. There is no trend that contribution of RHS to the short

hairs is less and to long hairs is more, or vice versa. None of the 3 parameters affects the contribution of

RHS and LHS to the protruding hairs significantly at least for

8 International Journal of Fiber and Textile Research 2012; 2(2): 5-11

Table No. 1: Three levels of factors

Treatments (-1) (0) (1)

Hank of Roving 0.4 0.55 0.7

Twist Multiplier 3.6 4 4.4

Traveller No. 1/0 2 4

Table No. 2: Parameters for Each Run

Run Number Traveller No. Roving Hank TM

1 4 0.4 3.6

2 4 0.55 4.0

3 4 0.7 4.4

4 2 0.4 4.4

5 2 0.55 3.6

6 2 0.7 4.0

7 1/0 0.4 4.0

8 1/0 0.55 4.4

9 1/0 0.7 3.6

Table No. 3: Contribution of RHS to protruding hairs/cm (PH/cm)

Run

No. PH/cm

RHS

%

PH/cm

2-4 mm

(%)

4-6 mm

(%)

6-8 mm

(%)

Above 8

mm

(%)

RHS%

2-4

mm

RHS%

4-6mm

RHS%

6-8

mm

RHS%

above

8mm

1 6.8 47.1 77.5 19.0 1.5 2.0 47.6 45.6 45.2 42.0

2 6.1 45.4 75.0 21.5 1.2 2.4 47.3 41.0 35.9 36.7

3 3.1 46.2 77.8 22.0 0.2 0.0 46.5 45.2 0.0 0.0

4 6.0 48.9 77.6 20.3 0.4 1.8 51.0 45.9 0JJ 29.4

5 5.3 39.9 81.7 14.5 1.3 2.5 42.8 28.3 0.0 30.6

6 2.0 44.6 87.4 12.3 0.3 0.0 44.9 42.7 0.0 0.0

7 4.6 47.9 79.9 17.9 0.4 1.8 50.1 39.8 0.0 43.3

8 4.3 35.9 78.6 16.9 4.2 0.3 38.9 25.4 24.9 27.1

9 1.2 55.0 83.9 9.3 6.6 0.0 57.5 41.6 42.9 0.0

Table No. 4: Contribution of RHS to loops/cm

Run

No.

Loops/

cm

RHS

%

Loops/cm

2-4 mm

(%)

4-6 mm

(%)

6-8 mm

(%)

Above 8

mm

(%)

RHS%

2-4

mm

RHS%

4-6mm

RHS%

6-8

mm

RHS%

above

8mm

1 2.9 51.7 67.9 25.4 3.5 3.2 51.6 49.4 55.3 40.0

2 2.0 40.2 79.7 17.4 1.7 1.1 39.5 43.5 36.7 46.4

3 0.9 39.8 90.8 8.8 0.4 0.0 39.1 41.5 75.0 0.0

4 1.8 52.2 71.7 21.8 3.4 3.1 52.5 54.5 55.7 30.6

5 2.0 45.1 79.9 16.0 1.3 2.7 38.8 44.9 54.2 53.1

6 0.3 29.2 95.5 4.5 0.0 0.0 28.3 45.8 0.0 0.0

7 1.2 47.1 69.5 25.9 3.1 1.9 47.8 45.4 46.8 43.3

8 1.3 27.8 77.2 20.1 2.7 0.0 29.4 21.7 22.1 0.0

9 0.2 45.6 74.4 40.6 0.0 0.0 55.2 32.1 0.0 0.0

2-8 mm protruding hairs (Table 5). Roving hank and TM

affect the contribution of RHS to the hairs above 8 mm. Effect of roving hank on the long hairs is more than that of

the TM. None of the factors studied shows significant

influence on contribution of RHS and LHS to the loops.

It is a general assumption that in a Z-twist yarn,

what with fibres at the left hand fringe are apart from the main fibre assembly, only LHS must be more and more

responsible for the formation of the protruding hairs.

But present study shows that contribution of RHS to the

9 International Journal of Fiber and Textile Research 2012; 2(2): 5-11

Table No. 5: P - values

Sr.

No. Parameter Traveller No. Roving Hank TM

1 PH/cm 0.003 0.001 0.14

2 RHS% PH/cm 0.929 0.399 0.801

3 2-4mmhairs (%) 0.01 0.000 0.026

4 4-6mm Hairs (%) 0.048 0.022 0.393

5 6-8mm Hairs (%) 0.38 0.09 0.61

6 Above 8mm hairs (%) 0.24 0.06 0.28

7 RHS% 2-4mm PH 0.908 0.542 0.824

8 RHS% 4-6mm PH 0.322 0.150 0.798

9 RHS% 6-8mm PH 0.297 0.152 0.321

10 RHS% Above8mm PH 0.068 0.003 0.043

11 Loops/cm 0.028 0.012 0.095

12 RHS% Loops/cm 0.884 0.342 0.547

13 2-4mm Loops (%) 0.049 0.022 0.189

14 4-6mm Loops (%) 0.168 0.039 0.209

15 6-8mm Loops (%) 0.548 0.133 0.542

16 Above 8mm Loops (%) 0.201 0.087 0.162

17 RHS% 2-4mm Loops 0.885 0.417 0.586

18 RHS% 4-6mm Loops 0.103 0.137 0.479

19 RHS% 6-8mm Loops 0.538 0.622 0.697

20 RHS% Above 8mm Loops 0.585 0.176 0.399

Table No. 6: Factors affecting contribution of RHS to hairiness and hair length distribution

Sr.

No. Factors Level Hairs /cm

RHS %

(hairs/cm)

RHS %

(2 -4 mm)

RHS %

(4-6 mm)

RHS %

(6-8 mm)

RHS %

(above 8 mm)

1 Traveller 1/OS 5.33 46.23 47.13 43.93 27.03 26.23

2 Traveller 2S 4.33 44.46 46.23 38.96 0.00 20.00

3 Traveller 4S 3.36 46.26 48.83 35.60 22.60 26.23

4 Hank 0.4 5.80 47.96 49.56 43.76 15.06 38.23

5 Hank 0.55 5.23 40.40 43.00 31.56 20.26 31.46

6 Hank 0.7 2.10 48.60 49.63 43.16 14.30 2.76

7 TM 3.6 4.43 47.33 49.30 38.50 29.36 26.96

8 TM 4 4.23 45.96 47.43 41.16 11.96 26.66

9 TM 4.4 4.46 43.66 45.46 38.83 8.30 18.83

protruding hairs and loops is about 40%, that too for both the doff positions. This means that due to the pre-twisting,

contribution of RHS of the triangle to the hairs is reduced

only by 10%. The reason may be as follows. Not all the fibres

at RHS are under good control and configured or arranged

well. There are some edge fibres that are expected to form

hairs. It is reasonable that very less fibre tails are under

control due to twist when they leave the nip of the front

rollers; and therefore, it is expected that most of the fibre tail

protrudes out of the triangular plane as yarn rotates and form

hairs.

3.2.2. Effect of roving hank Finer hank of roving is favourable for all the parameters

(Table 6). The most important conclusion that can be drawn

from the results is that finer roving not only reduces number

of protruding hairs and loops, but also lowers proportion of

long protruding hairs and loops. The contribution of RHS to

the long hairs drops down for medium hank of roving and

again increases for finer hank of roving; but this effect is not

significant (Table 5).

Roving hank affects protruding hairs of all length

categories (Table 7). It is reasonable because roving hank and

10 International Journal of Fiber and Textile Research 2012; 2(2): 5-11

Table No.7: Factors affecting hair length distribution

Sr.

No. Factors Level

hairs between

2-4mm (%)

hairs between

4-6mm (%)

hairs between

6-8mm (%)

hairs above

8mm (%)

1 TR 1/OS 76.76 20.83 0.96 1.46

2 TR 2S 82.23 15.70 0.66 1.43

3 TR 4S 80.23 14.70 3.73 0.7

4 HK 0.4 78.33 19.06 0.76 1.86

5 HK 0.55 78.43 17.63 2.23 1.73

6 HK 0.7 83.03 14.53 2.36 0.00

7 TM 3.6 81.03 14.26 3.13 1.50

8 TM 4 80.76 17.23 0.63 1.40

9 TM 4.4 78.00 19.73 1.60 0.70

draft decides width of the out -coming fringe, which in turn

decides number of hairs. Coarser roving produces more

number of long hairs. The reason is that use of coarser roving

and high draft spreads the fibres in the fringe, and thus

increases the width of the out-coming fringe. And therefore,

convergence point of a spinning triangle cannot grasp all the

fibres, especially at the edges, that lead to an increase in

number of edge fibres. Again, these edge fibres have to follow

a longer path to get their leading part wrapped around the

yarn. Therefore, it is expected that when their trailing end

emerges from the nip of the front roller, they produce long

hairs. This effect is pronounced more in case of coarser

roving, high draft, lighter traveller and low TM.

3.2.3. Effect of traveller

After roving hank, traveller weight is the second most

important factor that affects the protruding hairs and loops

significantly (Table 5). Heavy traveller reduces yarn hairiness

Table No. 8: Factors affecting loops

(Table 6–8). It also lowers proportion of long protruding hairs and loops, but only up to a certain extent. The present study

shows that proportion of long protruding hairs and loops

comes down for medium traveller; and for heavy traveller of

no.4, it again shoots up. Contribution of RHS to the long hairs

also follows the same trend.

Light traveller produces more number of long hairs.

Weight of traveller decides the spinning tension and size of

triangle. When tension is less, yarn moves sideways more

frequently and this will lead to increase the formation of long

hairs. It also increases the contribution of RHS to the

protruding hairs. Spinning triangle is larger for lighter traveller, and therefore, fibres have to follow a long distance

to reach convergence point and they will protrude easily.

3.2.4. Effect of twist multiplier TM has no significant effect on protruding hairs and

contribution of RHS to protruding hairs (Table 5). It shows no

definite trend for the RHS contribution to the hairs of different

length. However, it shows that TM does affect hairs of 2-4

mm significantly. TM affects formation of loop, though not

significantly. High TM reduces spinning triangle and also

reduces slackness of the fibre.

4. Conclusion

In this study the mechanism of formation of yarn hairiness is

observed with the help of series of photos by means of a CCD

camera. From images obtained, it is clear that for a Z- twist yarn, twist flows in the right hand side of the fringe, but not

all fibres at the right hand side are accumulated. Loops are

Sr. No. Factors Level

Loops

between 2-

4mm (%)

Loops

between 4-

6mm (%)

Loops

between 6-

8mm (%)

Loops above

8mm (%)

1 TR 1/OS 79.46 17.20 1.86 1.43

2 TR 2S 82.36 14.10 1.56 1.93

3 TR 4S 73.70 28.86 1.93 0.63

4 HK 0.4 69.70 24.36 3.33 2.73

5 HK 0.55 78.93 17.83 1.90 1.26

6 HK 0.7 86.90 17.96 0.13 0.00

7 TM 3.6 74.06 27.33 1.60 1.96

8 TM 4 81.56 15.93 1.60 1.00

9 TM 4.4 79.90 16.90 2.10 1.03

11 International Journal of Fiber and Textile Research 2012; 2(2): 5-11

formed due to slackness in the fibre and poor fibre alignment

in the fringe. Length of the hairs is not confined by the size of

the triangle in case of poor alignment of the fibres in the

fringe. Any disturbance in triangle zone increases yarn

hairiness. When yarn moves towards one side of the fringe, it

manages to catch edge fibres from that side, but fibres coming from other side have to follow a long path, and thus they will

produce long hairs. Yarn must be stable to reduce hairiness.

In this study effect of process parameters on

contribution of right hand fringe and left hand fringe on the

hairiness and hair length distribution is also studied. From the

results it can be deduced that contribution of left hand side of

the fringe to the protruding hairs and loops is above 60%.

None of the 3 parameters affects the contribution of RHS and

LHS to the protruding hairs and loops significantly at least for

2-8 mm protruding hairs. Roving hank and TM affect the

contribution of RHS to the hairs above 8 mm. Effect of roving

hank on the long hairs is more than that of the TM.

References

1) W.E. Morton, K. C. Yen, The Arrangement of Fibres in Single Yarns, Journal of Textile Institute. 60 (1952).

2) W.E. Morton, The Arrangement of Fibres in Single Yarns,

Textile Research Journal. 26 (1956) 325-331

3) A. Barella, Yarn Hairiness, Textile Progress. No. l, 1983

4) Stalder, High Performance Ring Spinning, Melliand. 72

(1991) 585.

5) W. Klein, Spinning Geometry and Its Significance,

International Textile Bulletin. (1993) p.2

Source of support: Nil; Conflict of interest: None declared