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Saturday, January 26, 2019

PINHOLES IN THE FABRIC, A FABRIC DEFECT, A WEAVING DEFECT, CAUSES, AND REMEDIES

PINHOLES IN THE FABRIC A FABRIC DEFECT, A WEAVING DEFECT CAUSES, AND REMEDIES:

The pin holes in the fabric are very small holes appeared in the fabric. "These pinholes get generated when either one – two adjacent picks or one-two adjacent ends are broken at the same place on the fabric surface".



Sometimes both end and pick are broken at the same place on the fabric surface. This defect becomes much serious when the frequency of pinhole increases highly.

Many times these holes are not visible during grey fabric inspection. These can be seen clearly in the grey fabric when the bottom light of inspection machine is kept on and top light is kept off.

Mainly these pin holes are generated during weaving in the fabric. The emery of the take-up roller is responsible for these pin holes. If the emery of the take-up roller becomes smooth, then the slippage occurs between take-up roller and fabric. This slippage causes a rupture in the warp or weft in the fabric at many places. This yarn rupture results in the form of pinholes in the fabric. Sometimes the cloth winding tension is more than standard. The surface speed of cloth winding roller becomes slightly higher than the surface speed of cloth take-up roller. This surface speed difference between cloth take-up roller and cloth winding roller creates slippage between fabric and cloth take-up roller. This slippage causes yarn rupture in the fabric at many places. This yarn rupture results in form of pinholes in the fabric.

If warp or weft yarn has high thin places, then there is always a chance of broken warp or weft for very small length ( one or two threads). These threads are broken in the fabric after weaving due to jerk creating during shedding or beating.

If the fabric has been woven with the yarn which has a very high degree of thin places and the fabric is woven safely with this yarn without generating pinholes, then there is always possibilities of yarn rupture during processing. When the fabric passes under tension during processing, the yarn at thin places breaks and pinholes appears on the fabric surface.

If our grey fabric is ok in all respects and pinholes appear in the fabric after processing. This may be happened due to improper filtration of caustic solution during boiling. Excessive fabric tension during processing on jigger machine or the stenter machine also causes pinhole in the fabric. Some times fabric gets burnt during singeing due to improper neutralization of protruding fibres or fluff. 
                                

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