Fell Position
Position shifts of the fabric boundary during loom stops can cause thin or thick start-up marks in the woven cloth. The occurrence of fell displacement alters the distance between the last woven pick and the reed at the moment of the first beat-up. This shift must be prevented to maintain a flawless fabric appearance.
Loom Stoppage
When the loom stops due to a warp or weft break, the motor shuts down and the yarn tension changes. This change can trigger fell displacement as the fabric creep pulls the fell away from the reed. When the loom restarts, the reed beats up at a slightly different position, creating a defect.
Tension Relaxation
Synthetic yarns exhibit viscoelastic behaviour and relax under constant load. During a prolonged stop, this relaxation worsens the fell displacement because the warp sheet loses tension. Polyester warps are particularly prone to this tension loss during stops.
Correction Cycle
Modern weaving machines use electronic take-up and let-off motors to adjust the fabric position before restarting. This cycle corrects the fell displacement by moving the cloth back or forward to its correct coordinates prior to the first active pick. This automated electronic compensation minimizes start-up marks and maintains uniform density across the fabric surface, even after prolonged mechanical stops.
