Friday, 7 November 2008
Common Weaving Defects-2
A float or Jala is formed when there is no proper interlacement of the warp and weft yarns over a certain area. The remedial measures are the use of overall high warp tension and keeping the lease rods close to the heald shafts.
Weft Crack (Jerki)
A srip in the fabric where the pick density is lower than normal is calld a weft crack or jerki
Crammed Pick (Patti)
A strip in the fabric where the pick density is more than normal is called a patti. The defect is caused by improper setting of the anti crack motion.
The defect is caused when many ends break consequent to a shuttle trap. The important causes of shuttle trap are : wrong timing of shedding, soft picking, insufficient checking of shuttle in the boxes, severe slough off, and damaged or broken picking accessories.
A weft slough of one or two coils. the main causes of slough are softly wound pirn, overfilled pirns, high density of coils, short chase length etc.
Improper Weft Threading (Single Moti)
The defect is characterised by a loose and uneven selvedge consisting of weft and warp protroduing loosly beyong the true selvedge line.
Hardened fluff, as well as foreign matter such as piece of leather accessories or wood chips, woven into the texture of the fabric is called a gout.
In this defect, the yarns are distorted from their true paths and fine holes are caused near the selvedges. Unsuitable choice of temples and poor mechanical condition of temples are the main causes of this defect.
The defect is characterised by uneven and distorted appearance of the fabric, because of hard gummed spots in the warp. Use of cold size or keeping the immesion roller dipped in size during a long machine stop causes such spots.
Stains are caused by lubricants and rust. Most of the stains can be traced back to poor manintenance and material handling.