28-09-2012, 10:44 AM
SPINNING DEFECTS
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Spinning faults:
Bullets:
Bullets are low twisted double yarn seen weft wise in fabrics. Those are generally zero
twisted parallel yarns. Practical causes of faults are,
1) Proper functioning of bunch motion is not there.
2) Incorrect yarn path through spindle.
3) Loose tensioners.
4) Capsule and spring working.
5) In-sufficient length of yarn as bunch.
6) Knot is not applied after removing the Bunch yarn.
Hard twist -due to low take-up speed
1) Bobbin holder adopter
2) Cradle setting and its pressure.
3) Friction ring,
4) Winding tension
5) Yarn lapping over feed roller.
6) Winding roller.
7) Faulty and damaged bobbins should be discarded.
General reasons:
1) Lapping on disc.
2) Spindle and capsule working.
3) Overfeed variation.
4) Dial and overfeed tensions varies.
5) Trolley knocks over breaks so placed rails at bottom on floor.
6) Scratches on drum.
Bottom:
Remnant/Left over yarns of different shades, counts, twist lappets onto bobbins gives
bottoms.
1) Remnant of Ring frame cops.
2) Yarn used for lappets, during start of materials has to be of same shade/same
count.
3) Remnant double yarn on TFO Bobbins should be cleaned.
4) Red separator on Ring frame to segregate different shades.
5) Lot change at Auto- winding if cop is not changed.
6) Remnants yarn to be cleared from the Ring Bobbins & cheeses
Cork Screw:
One yarn is straight and other one is twisted on it.
It is caused due to deposition of fibres foreign particular etc, to yarn during spinning
stage which causes objection in fabric. In-sufficient tension during TFO, different
tension levels at parallel winding m/c. yarn released during knotting at parallel winding
causes screw of yarn over other yarn gives cork-screw effect.
Contamination:
This is due to mixing of different shades of fibres, foreign materials etc. during spinning
stage causes visual objection in fabric. The causes of Contamination depends on:
1) Overall cleanliness of department.
2) Cleaning of machine after every doff and lot change.
3) Suction of drafting zones of Gill boxes and Rovings.
4) Cleaning of scrapper and scrapper plate cleaning after every lot change of doff.
5) Use of curtains for partition in Ring Frame and Two for One to separate light and
dark shade during running of m/cs.
6) Overhead cleaners of Ply. Winding, Machconer and Ring frame.
7) Not to run contrast shades side by side of M/c. of Ring frame and TFO.
8) Material should be covered with polythene sheet to avoid fly and fluff
accumulation.
9) Do not use compressed air for cleaning m/cs.
10) Use only vacuum cleaner.
11) Air conditioning should not be common for Dyed spinning and White spinning
Sections because of common ducts for return and supply air.
Count variation:
Difference in count compared to require count.
Fabric gives bad appearance and characterized by variation in density. The variations of
lower and higher side for long and medium type. Probable reasons for this are:
1) Regular check on wrapping from Gill box to Ring frames.
2) Correct piecening of silver or that portion should be removed from the delivered
sliver.
3) During run out of material extra care is required to take.
4) Auto-leveller setting is to be checked for fault and material of below Std. Uster
value to be taken back for processing.
5) Top cots rollers condition at Gill boxes, Rovings and Ring frame.
6) Tension at Roving and Ring frames vary. Barrels at Roving should move freely.
7) Top arm pressure, spacer, condenser and drafting zone condition of spinning frame.