Weaving Defect
Structural fabric irregularities characterized by localized pick density variations appear across the woven width when a loom resumes operation after an interruption. Fabric inspectors identify starting marks during grey cloth inspection to grade fabric quality and determine cut lengths. The defect presents as either a dense band of crowded weft threads or a thin open strip of sparse picks.
Boundary conditions cover woven cloth inspection prior to finishing and cut-piece grading.
Density Variation
Loom stops caused by warp breaks or weft supply changes allow tension relaxation along the warp sheet and woven fabric roll. When the loom restarts, the first few pick insertions occur under altered tension conditions before automatic let-off and take-up mechanisms regain steady-state operation. Chinese weaving mills equip rapier and air-jet looms with automatic starting mark prevention devices that adjust the back rest roller position and take-up drive on the initial restart pick.
Improper loom brake settings or incorrect warp tension compensation produce visible bands that persist through wet finishing operations. Fabric inspectors tag starting mark locations and penalize fabric rolls according to standard four-point grading rules.
Loom Adjustment
Preventative maintenance programs require routine calibration of electronic let-off and take-up motors. Loom technicians fine-tune restart delay cycles to match specific yarn elasticity profiles. Eliminating starting marks increases first-quality fabric yields in commercial linen manufacturing.