Defects in Fabrics
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Transcript of Defects in Fabrics
SANALRAJ.M.KJWM/OFIL
Fabric defects can be classified in to following categories:
1) Warp defects2) Weft defects3) Cloth defects
Warp breakages or Broken endsThis defect is due to :
1) Weak warp 2) Warp tension exceeds yarn strength.3) Damaged or obstruction in the yarn
passage.
This due to;1) Broken ends that are not mended
properly.2) Defective warp stop motion
this is the most frequently occurring defect in fabric constituting 40-50% of the total defects.
Wrong endsWhen more than one end breaks at the same time
there is a probability that they may be drawn through wrong healds.
Selvedge defects.Wavy selvedges are due to unequal tension put
upon the ground and selvedge ends either in the warping and sizing machines.
Too strong temples may also cause wavy selvedges.
Small loops in selvedges are due to insufficient tension in weft winding.
Floats This is formed when there is no proper
interlacement of warp and weft yarns over a certain areas.
Warp streaksThis is a dense strips running along the
warp direction of the fabric. This is due to variation in the density of adjacent groups of warp ends because of non uniform dent spacing, wrong drawing in of ends through reeds or difference in count of yarn.
Broken picksThis is due to breakage of weft yarn and it
is not removed in time.Thick and thin placesThin place is due to faulty take up motion
where two teeth of the take up gear are moved instead of one.
Thick places are due to take up motion missing and failing to turn the cloth roller.
Weft loopsThese are the loops projected from the
surface of the fabric. This is happens when a small portion of weft is caught by the warp threads forming the loops.
Weft barsWeft bar is a dark or light band across the
width of the fabric which shows up prominently , particularly in dyed fabrics. This is due to count difference , difference in blend composition, differnce in twsr, colour or shade.
Weft Cracks This is due to thin place or missing weft
acres the body of the fabric. This is due to weaver not adjusting the fell of the cloth at the time of starting of the loom.
Weft snarlsThis is due to loosely wound weft yarn.
Stains This is due to oils , lubricants, or rust.Patchiness
This is characterized by small , irregularly shaped elongated areas of dense and bare cover through out the fabric . Patchiness is more prominent in light shade fabric, this is due to increase in yarn unevenness in any direction.
ReedinessThis is due to grouping of warp ends drawn
through individual dents of the reed ith a fine crack showing up gap in between.
Temple marksIn this defect the yarns are distorted from
their true paths and fine holes are caused near the selvedge. Reducing the no of rings can minimize the defect.
Starting marksA strip in the fabric where the pick density
is lower than normal is called a weft crack. This is due to faulty let off or take of motion.
GoutHardened fluff, foreign matter such as
pieces of leather accessories wooden chips woven in to the fabric is due to gout.
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