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HAIRINESS IN YARN - 2

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RING COPS TRAIL (BOTTOM  POSITION OF THE RING RAIL)

PARAMETERS old lmw rings new lmw rings bracker rings
NOMINAL COUNT 30s CH 30s CH 30s CH
U% 9.24 9.18 9.24
Thin (-50%) 0 0 0
Thick (+50%) 26 19 27
Neps (+200%) 49 44 46
Total IPI 75 63 73
Hairiness Index 6.11 6.06 6.22
Sh(-) 1.27 1.26 1.29

 You would note from the above trials that:

 a)    There is no significant difference in hairiness between Imported & Indian rings.

b)      There is also no significant difference in hairiness between a new and a one-year-old ring.  However if the condition of the ring is highly worn out  ,  it will affect the hairiness. In short the ring and traveller do not play a major role on hairiness compared to other process parameters, which are explained below.

 3) SPACER SIZE: Size of the spacer plays significant   role in reducing the hairiness.  Many technicians have a tendency to use the thinnest spacer   for reduction in U% and imperfections.   However it leads to significant  increase in hairiness.  A study conducted recently at a leading mill proves this point.    Please refer the table below for the above study.

 EFFECT SPACER SIZE ON HAIRINESS

  Ring rail bottom position Ring rail Top position
COUNT 24s CH 24s CH 24s CH 24s CH
ROVING HK 0.8 0.8 0.8 0.8
SPACER 3.0 4.0 3.0 4.0
U% 8.7 9.06 8.58 8.76
thin (-50%) 0 0 0 0
thick (+50%) 8 15 7 12
Neps (+200%) 14 16 16 19
Total IPI 22 31 23 31
Hairiness Index 7.32 6.72 5.87 5.35
Sh(-) 1.27 1.19 1.07 1.06

 

You would note from the above that there is a significant reduction in hairiness by using thicker spacer.  However the imperfection has also increased.  .

The spacer should be selected such that optimum results are achieved with respect to imperfections as well as hairiness.  We request you to conduct a trial with a spacer, which is 0.5 to 1mm thicker than the existing spacer.  It is needless to mention that using thicker spacer will increase the imperfections.  However if the reduction in hairiness is more significant than increase in imperfections it can be allowed.

4) TPI IN THE YARN: Increasing the TPI leads to reduction in hairiness and this is more significant in the case hosiery yarn.  Hence if the hairiness is a bigger problem faced by mill, trials can be conducted by increasing the TPI up to the allowable limit for achieving reduction in hairiness. 

5) LAPPET HEIGHT:  Reduction in lappet height leads to direct reduction in hairiness.  However care should be taken to ensure that the yarn does not touch the tip of the Empties.  Please conduct trials with reduced lappet height (Formula: Lappet height = 2D+5mm).   

6) SUCTION TUBE SETTING:  The suction tube should be set such that the yarn does not touch the tip of the suction tube in running.   If the yarn touches the suction tube due to improper setting, it will lead to increase in   hairiness.

7) TRAVELLER SIZE:  Usage of heavier traveller leads to reduction in hairiness. 

For Example: If the breakage rate in 30s carded hosiery count is same with 4/O and 6/O traveller, using 4/O traveller will give lesser hairiness than 6/O traveller. 

8) LIFT AND RING DIAMETER:  Using lesser lift and lesser ring diameter will lead to direct and significant reduction in hairiness.  

For Example:  If 30s carded hosiery count is spun with 170/38 and 180/40 combination, spindle speeds remaining the same, the former combination will give much lesser hairiness than the later combination because of a reduction in the height and diameter of the yarn balloon while spinning. 

C) CONE WINDER:

There will be a significant difference between the hairiness of the yarn at cop stage and at cone stage.   The cone winding process increases the hairiness by 15 to 20%, which is unavoidable.  However, if the modern AutoConers are not tuned properly, it will lead to increase in hairiness of much more than 20%.  In this case the following points need attention.

1.    WINDING SPEED:  The speed of winding plays a significant role on increase in hairiness.  The increase in winding speed leads to direct increase in the hairiness.    The results of the study conducted recently at a leading mill are given below for your reference on this point. 

EFFECT OF WINDING SPEED ON HAIRINESS
PARAMETERS Cop result winding speed

1200 m/min

winding speed

1400 m/min

winding speed

1600 m/min

NOMINAL COUNT 30 s CH 30 s CH 30 s CH 30 s CH
U% 9.37 9.59 9.6 9.53
Thin (-50%) 0 0 0 0
Thick (+50%) 16 14 15 17
Neps (+200%) 39 41 41 50
Total IPI 55 55 59 50
Hairiness Index 5.04 7.13 7.47 7.5
Sh(-) 1.08 1.59 1.66 1.73

 You would note from the above that the hairiness increases more  and more with the increase in the winding speed.  However it is not economically feasible to run the AutoConer at slow speed just for                      achieving lesser hairiness.  But all the AutoConers have a provision to adjust the speed of winding according to the stage of the cop and this is called variable speed arrangement.  By selecting the right speeds at different stage of the cop the increase  in hairiness can be controlled to a great extent.

 2.    YARN TENSION DURING WINDING:  By optimizing the yarn tension the increase in hairiness can be controlled.  The results of the study conducted recently at a leading mill are given below for your reference on this point.

PARAMETERS tension 25 grams tension 32 grams
NOMINAL COUNT 30/1 CH 30/1 CH
U% 9.73 9.68
Thin (-50%) 0 0
Thick (+50%) 23 19
Neps (+200%) 52 48
Total IPI 75 67
Hairiness Index 7.41 7.72
Sh(-) 1.74 1.79

You would note from the above that the hairiness can be reduced by optimizing the winding tension.  This trial may be conducted at your  mills for controlling the hairiness.

3.    WAX PICK UP:  It is the normal practice of many mills to apply wax on the hosiery yarn during winding.  By controlling the wax pick up, the increase in hairiness can be reduced.  The detail of the study recently conducted at a leading mill is given below for your reference. 

EFFECT OF WAX PICK UP ON HAIRINESS

 

PARAMETERS wax pick up 0.8 gms/kg wax pick up 1.2 gms/kg
NOMINAL COUNT 30/1 s CH 30/1 s CH
U% 9.84 9.91
Thin (-50%) 0 1
Thick (+50%) 32 30
Neps (+200%) 89 112
Total IPI 121 1459
Hairiness Index 8.13 7.89
Sh(-) 1.84 1.87

We request you to conduct a study of this aspect at your mills for control of hairiness. Thus, there are several process parameters that can be optimized for controlling the hairiness.  Unless the ring and traveller are in a worn out condition, the role played by the ring and traveller on hairiness is quite negligible on modern ring frames like LG5/1 and LR/6.

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