Common Yarn Faults in Manmade Fibres

Common Yarn Faults in manmade fibres

1. Slubs:

Slub like thick faults seriously mar the appearance of fabrics made from manmade fibres. The following measures can be taken

A. In Blends with cotton

a. properly select the cotton component
b. ensure proper grinding of wirepoints at cards
c. regularly check the ringframe drafting system.

B. In 100% manmade fibres

a. Ensure adequate number of doublings
b. avoid too wide a roller setting and inadequate weighting on rollers.
c. Select correctly the fibres in regard to their compatibility in length.

2. Crackers

This defect is characterised by the cracking sound produced when the yarn is pulled. The sound is produced due to sudden rupture of fibres curled around the yarn.

- Crackers are caused mainly by the presence of very long fibres due to improper cutting of the two.

- They can also be caused due to high vairability in the elongation of the constituent fibres in the blend.

- Ensure wider roller setting in the back zone, adequate roller weighting and avoid too narrow a spacing between the aprons.

- It is helpful to have low roving twist and higher spinning tension through the use of heavier traveller.

3. Neps

This can also mar the appearance of a fabric

- In man made fibres longer and finer fibres tend to produce more neps.
- Other reasons of neps are
- Excessing beating of fibres in the blow room
- Loading of licker-in or cylinder at card
- Blunt wire points on various carding elements
- excessive lap weight

4. Fluffy Yarn

In general presence of short fibres and proneness to static accumulation tend to produce this defect.

The fault can be corrected by maintaining proper atmospheric conditions and reducing the fluff on roving.

5. Smoky Yarn

- The yarn containing synthetic fibres get smoky through long exposure of the running bobbin in a dirty atmosphere in the ring spinning system.

- Installation of smoke filters in H-plant can correct the problem

- Use of roving build can check this defect.

Tsudakoma ZAX- Settings for standard Denim

Tsudakoma-ZAX Loom Settings for 14.5 Oz/Sq yd OE/OE Denim (EPI x PPI = 64 x 37) count (6s x 7s)


Back Rest- 125 mm (vertical)
-16th mark ( horizontal)

Dropper Box- 100 mm (vertical)
- 50 mm (vertical)

Shedding Amount

1st Frame- 99 mm
2nd Frame-91mm
3rd Frame- 83 mm
4th Frame- 75 mm

Heald Frame Height:

1st Frame - 43 mm
2nd Frame-41mm
3rd Frame-39mm
4th Frame- 37mm

Shed Crossing Timing- 290 deg

Leno Crossing Timing- 290 deg ( LH Side), 0 deg ( RH side)

Temple- 15 rings- Medium Type

Sub Nozzle angle- 4 deg
Sub nozzle height- 3rd Mark
Machine Pulley- 220 mm
Motor Pulley- 113 mm for 760 rpm

iboard Settings

Tension- 280 kgf
Upper Limit- 560 kgf
Lower Limit- 0 kgf
Pick Density- 37 pick
Turns/Pick- 4
Arrvial setting - 240 deg
Filling insertion timing- 80 deg
No. of Sub groups- 5

Timing

Feeler H1- 200 deg to 290 deg
H2- 200 deg to 310 deg
Forward- 350 deg
Rev (others)- 180 deg/320 d eg
(Filling)- 290 deg
WBS- 240deg-300deg

SENSOR/TROUBLE
Dropper Setting: 10 th Volume
Sensor- on
Feeler-on
Timing

Pin: 50deg-200 deg
Main: 50deg-200deg
AUX Main: 60deg-100deg
80deg

Auxiliary Nozzle- 76 deg-176 deg
1st Pick- 86 deg

Sub Nozzle

64deg-170 deg
100deg-190deg
130deg-220deg
150deg-230deg
170deg-250deg

Stretch Nozzle- 200deg-300deg

STOP MARK Data

1. F Kick ( Filling) - 0 upto 7 steps
2. F Kick (Others)- 0 upto 7 steps
3. R Kick ( Filling)- 0 upto 7 steps
4. R Kick (Others) - 0 upto 7 steps
5. Kick Back Speed- 1. Low 2, Medium 3, High On
6. Kickback order- on 1

1. Rev to Forward
2. Forward to Rev

7. Down time- 5 min
8. Fell Control-8
9. Dia Comp-48
10. Let Off Avg-2
11. F-Gain-0
12. R.Gain- 0

13. Gain -1
1. Low
2. Medium
3. High

14. Rush Torque- 1200%
15. change Picks-2
16. Change timing- 30 deg
17. 1 pick insertion- On
18. Autolevelling- On

Critical Process Parameters- Denim Manufacturing

Critical Process Parameters- Denim Manufacturing

Warping:

Machine Speed m/min= 600+-50
Tension on individual thread ( cN) 90+-30
Warping breaks ( Avg/10000m/400 ends) < = 0.2

Dyeing-cum-Sizing

1. Machine Speed = 30+-2
2. Size Viscosity ( Flow seconds) = 6+-1
3. Size Add on ( %)= 6+-2
4. Breaking Force (gf) sized yarn = >=1100
5. Tenacity ( cN/tex) ( sized yarn) = >13
6. Elongation ( %) of sized yarn >= 4.5

Finishing

Quality	7 x 6	7 x 6	7 x 7	7 x 9	7 x 6
Width(cm)	151+-1	149+-1	151+-1	151+-1	151+-1
Shrinkage ( %)	15+-1	14.5+-1	15.5+-1	16+-1	14+-1
Skew ( %)	5-11	5-11	5-11	5-11	5-11