Four Point Inspection Procedures for Woven Linen Greige Cloth Quality Control
Standardized four-point greige inspection prevents downstream finishing losses by enforcing objective ASTM D5430 defect scoring before cloth conversion.
Loom Stop Bars
Density Variation
Fabric width bands showing alternative pick counts created when an insertion machine pauses and restarts mark distinct horizontal lines across flax cloth. Mill technicians track loom stop bars as structural density changes caused by stress relaxation in the warp sheet during downtime. The resulting band creates a visible light or dark line that alters fabric shade across the roll.
Mechanical Cause
Automatic stop motions halt the insertion system whenever a warp end snaps or a weft bobbin exhausts its yarn supply. Prolonged stoppage allows tensioned flax yarns to creep, while the take-up roller loses its precise angular synchronization with the main drive shaft. Restarting the machine without manually adjusting the fell position produces either a thin gap from insufficient pick packing or a dense bar from double beat-up.
Modern electronic let-off drives recalculate warp tension during downtime to minimize displacement, yet high-modulus flax fibres remain sensitive to micro-movements during motor acceleration.
Defect Evaluation
Mill quality inspectors measure the linear width and density deviation of each horizontal line under standardized trans-lit frames. Horizontal loom stop bars receive penalty points based on contrast intensity and length during grey cloth inspection before wet finishing operations. Light stop bars may diminish slightly during fabric washing and swelling, whereas heavy dense bars remain permanent structural flaws in the finished linen fabric.
Standard buyer grading criteria classify repetitive stop marks within three linear meters as major faults that justify roll rejection at the export warehouse boundary. Laboratory fabric testing documents whether the stop bar contains broken picks or localized yarn packing variations, providing clear data for loom maintenance personnel.