Fabric inspection Faults and their causes

Defects	Causes
Holes	Bad needle, take down mechanism too tight, high tension on yarn, bad yarn needle too tight in their slots, dial height too low or too high, badly tied knots, improper stitch setting.
Drop stitches	Takedown mechanism too loose, defective needles, too loose yarn tension not sufficient, wrong needle timing set, needle tricks closed.
Vertical lines	Defective needle, dirt in needle slots, needle too loose or too tight in the tricks, needles not enough lubricated.
Soiled yarn	Contamination of cones due to miss handling, knot tying with dirty hand.
Rust mark	Rusty needle, rust in tricks.
Slub	Broken filaments being pushed back along the thread line excessive tails of knitter knot.
Loop distortion	Bad and bent needles, bent trick walls, uneven yarn tension, needle timing set wrong, yarn carriers set wrong.