CAUSES FOR HIGH SLIVER VARIATION:
Too high a tension draft and stretching of web.
Size of the coiler trumpet not adjusted to the hank.
Side panel boards improperly secured.
Difference in drafts between cards.
Worn clothing and feed roller bearings.
CAUSES FOR NEP FORMATION IN CARDS:
Lap too heavy, close settings and higher lickerin speeds. Blunt Iicker_in wire or dull flats. Jammed wire on doffer. Rough surface in front and back plate.
Use of blunt grinding stone and inadequate or too high grinding frequency.
Insufficient striping.
Dirty under casings.
Doffer not stripped after lapping.
Undercasing choked with fly.
Waste packed between cylinder, doffer, and licker-in sides. Ends of front and back plates and milled ends of flats dirty.
Uneven flat settings.
lickerin set too far from feed plate.
High doffer speeds.
CAUSES FOR HOLES OR PATCHES IN CARD WEB:
Cluster of cotton embedded on cylinder wires.
Damaged cylinder/doffer/flat wires.
Poor flat stripping.
Hooked or damaged wires on flats.
Excessive fly and seed bits embedded on flat wire. Very close setting of front plate.
What are the essential requirements of the good carding operation? For effective carding action,
The wire surface of the cylinder should be in good condition i. e. should be close, sharp and clean.
Seed bits, honey dew and wax, if any present in the cotton will get crushed and pressed into wire points of the cylinder, this affects the carding operation. To avoid, this, petrol washing of cylinder wires are carried out once in a month.
Action of fibres and dirt with it, gradually, wear the wire points causing them to become poor carding operation. So, to maintain card clothing in a sharp condition, effective, sound system of grinding should be carried out once in a 6 months.
Embedding of fibers and impurities in the wire surface reduce the effectiveness of carding, so, stripping carried out.
A knowledge of optimum setting of the various organs of card is essential for successful maintenance of carding process.
Perfect control of air current also ensures god carding.
Good condition of B/R laps must be maintained.
