Wednesday, May 29, 2019

THICK END, THIN END, WEFT BARS, WEFT BANDS , CAUSES AND REMEDIES

Yarn count variation:
The yarn count plays a very important role in fabric quality. Any unevenness in yarn appear in the form of fabric defect on the fabric surface. Many times yarn count variation results as a big issue in respect of fabric defect. There may be two kinds of defects due to yarn count variation in the fabric.
Warp count variation:     Any kind of variation in the count of warp yarn results in the form of continuous thick end or thin end which is visible on the fabric. If warping if the beam has been done on sectional Warping machine, the thick or thin end appear in each section. If warping has been done on direct Warping machine, the thick or thin end appear at particular place in group. This kind of defect appear s only when one or more cones contain count variation in whole yarn length. This kind of uneven appearance of the fabric cause rejection of the fabric. The mending of this type of defect depends upon the type and length of the defected fabric. If the length is short say 2-3 meters and one or two thick or thin ends are appearing in the fabric, then mender can change this end with the same count of yarn. If the length is too high or there are many thick or thin end in the fabric, then the fabric gets rejected because the replacement of defective thread with the fresh thread is a much time-consuming process. If mending cost is more than fabric cost, then it is better to reject the defective fabric.




Weft count variation:

The weft count variation is a more serious issue than warp count variation. In the most time fabric gets rejected due to weft count variation. The weft yarn count variation affects the fabric surface in many forms. 
If the weft yarn count varies for a short length say 4 - 5 metres, the weft bars appear on the fabric surface. It can be repaired by replacing the defected pick by fresh yarn. 
If the weft count varies for a long length, it results in form of low and high thickness bands in the fabric. If there is very low count variation for long length, the bands do not appear clearly in the grey fabric. When this fabric is dyed , the light and dark colour bands appear prominently on the fabric surface.
If the weft yarn count variation occurs for long weft yarn length, the GSM of the fabric also varies. 
Individual weft bar can be repaired but GSM variation, thick and thin bands are not repairable. These irregularities are unacceptable. The whole fabric gets rejected due to these kinds of defects.


                                 THE END

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