| C |
Check & adjustment for length shrinkage |
| 1 |
Measure and mark 100 cm before the fabric enters the machines, measure the marked fabric exiting the machine. For every 1cm reduced, equals a reduction of 1% in shrinkage. OR use a measure specifically designed for checking fabric shrinkage after processing. |
| 2 |
Subtract the reduction in % length shrinkage from the fabric shrinkage (before processing) to give the calculated fabric shrinkage after processing E.g. 12% before processing; length reduced by 5%; calculated fabric shrinkage = 7%. Customer specifies a maximum of 8% length shrinkage. |
| 3 |
If the fabric length shrinkage is not known before processing; this measure will only indicate the amount of length shrinkage during processing, NOT the actual shrinkage of the fabric. |
| 4 |
To add ‘safety to the length shrinkage (fabric length increased on “rolling”) the calculate shrinkage after processing could be set at 1% to 2% below the customer targets. E.g. Customer specifies 8% shrinkage, calculated shrinkage = 7%. |
| 5 |
Stenter – To reduce or increases the length shrinkage by 1%, increase or reduce the overfeed by 5%. Re-check the % length shrinkage. |
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| D |
Check & adjustment for width & width shrinkage |
| 1 |
After processing measure the width of the fabric (could be overall width, useable width), compare to the target width. |
| 2 |
If the width is narrow/wide, increase/decrease the width of the chain by same number of cm. E.g. if fabric 175cm and target is 178cm, increase the chain width by 3cm. |
| 3 |
For calculating the width shrinkage (if shrinkage known before processing) Measure the width (cm) before and after processing, calculate the shrinkage. |
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example – calculate shrinkage |
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width before 170cm with 5% width shrinkage |
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width after 175 cm |
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175 – 170 = 5cm |
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5/175 x 100 = 2.86% |
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Total calculated shrinkage = 7.86% (5 + 2.86) |
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| E |
Check & adjustment of grams per square meter (g.s.m) |
| 1 |
Before checking the gsm, the width should be within specification |
| 2 |
Take a sample and cut the sample with a gsm disc cutter. Weigh the cut sample; compare to the target, minimum and maximum allowed gsm. N.B The target gsm could be conditioned or UN-conditioned. |
| 3 |
If the gsm is too high; the gsm could be reduced by reducing the overfeed. N.B Reducing the overfeed, increases the length shrinkage. Calculate the affect on length shrinkage before adjusting. |
| 4 |
If the gsm is too low, the gsm could be increased by increasing the overfeed (refer example below) by 10%, slowing down the compactor by 20%. |
| 4.1 |
Stenter – To reduce or increase the gsm, increase or reduce the overfeed by 8%. Re-check the gsm. |
| 5 |
Re-check the gsm after adjusting the overfeed. |
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| F |
Check & adjustment of fabric skewness |
| 1 |
The skew is measured by the deviation of the course line across the width against the width. |
| 2 |
Measure height of course traversed and the width of the fabric |
| 3 |
% skewness = height/(fabric width) x 100% |
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course |
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height |
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width |
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| 4 |
Compare the result against the maximum allowed skewness. |
| 5 |
For every 1% above the maximum allowed skewness, increase the angle of the courses straightner by the same %. Re-check % skewness. |
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| G |
Courses and wales |
| 1 |
Courses and wales can also be used to check if a fabric is within tolerance |
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| H |
Adjust of the machine does NOT achieve the width, gsm and shrinkages |
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Usually means the knitting or the dyehouse has affected the fabric in a negative way |
| 1 |
Stop processing the fabric; INFORM the finishing manager. |
