Loom Dynamics
Displacement of the woven fabric boundary during loom stoppages and restarts alters the pick density of the cloth. This fell migration creates visible defects known as set marks or start-up marks in the linen fabric. Weavers must adjust the let-off and take-up mechanisms to prevent this shift when the loom is idle.
Tension Factor
Relaxation of the warp yarns during a stoppage causes the boundary of the woven cloth to creep backward or forward. In linen weaving, fell migration is particularly pronounced because flax fibres have low elasticity and do not recover quickly from prolonged tension. The severity of the shift depends on the duration of the interruption and the ambient humidity of the weaving shed.
Fabric Defect
Variations in the pick spacing diminish the aesthetic quality and the structural strength of the linen cloth. When fell migration occurs, the resulting thick or thin bands are flagged during final inspection against buyer standards. Automatic defect scanners in Chinese finishing mills record these patterns to determine if the fabric must be downgraded to a secondary quality level.
Preventing these blemishes requires highly sensitive loom control systems that automatically compensate for warp relaxation during any pause in production.
