Loom Start-Mark Prevention and Stop Motion Management
topic
Start marks are bands of different weft density at the restart position after loom stops, caused by the fell displacement from warp tension changes during stopping and starting that alters the pick spacing in the picks immediately following restart, with prevention using programmed slow restart procedures that gradually increase speed while advancing the fell to compensate for the fell displacement that occurred during the stop, and with modern loom controllers incorporating automatic start-mark elimination sequences that restore fell position before resuming production speed.
Role
Prevents the commercially significant defect of start marks that occur at every loom stop and would cause extensive fabric downgrading without active prevention, with start-mark elimination being one of the most practically important quality management features in modern loom controllers that represents a significant advancement over earlier looms where each stop produced a visible start mark requiring operator intervention and frequently resulting in fabric waste from the defective zone around the stop position.