Standard Setup Rules for Four Point Greige Perches
Standard four-point greige perches require a 45-60 degree tilt, 1200+ lux D65 lighting, synchronized tension drive, and strict ASTM D5430 demerit point scoring.
Bast Fiber Irregularities
Defect Classification
Surface abnormalities in flax processing originate when mechanical scutching leaves residual shive embedded within continuous filaments or when hackling creates localized knotting known to spinners as bast fiber irregularities. Chinese export mills evaluate these physical inconsistencies during the intermediate sliver drawing stage, documenting each fault variance on the official mill quality control docket before yarns move toward commercial spinning frames. A raw fibre grade relies entirely on natural tensile strength and length distribution, whereas a processed fabric grade accounts for visual uniformity after loom operations.
Mill acceptance standards dictate internal production tolerances for spinning stability, while buyer purchase contracts establish strict exterior penalty limits for finished linen cloth delivery.
Detection Methodology
Electronic capacitance testers mounted on drawing frames register mass variations continuously by measuring changes in dielectric current as irregular fibre bundles pass through specialized condenser plates. Technicians calibrate these optical sensors against known mass standards daily to maintain absolute measurement integrity across long production runs without manual intervention. High-speed cameras capture surface profiles at the final winding station, comparing digital shadowgrams against preprogrammed thresholds for linear density fluctuations.
Processing Impact
Uneven sliver mass creates localized tension spikes during high-speed ring spinning, frequently causing premature yarn breakage and subsequent machine downtime on the factory floor. Weaving departments adjust shedding timing and warp tension profiles to compensate for localized yarn diameter swells, preventing reed marks and structural weaknesses in the final woven linen piece goods. Export inspectors reject woven lots containing excessive linear density anomalies because unpredictable dye absorption across thick sections ruins the visual consistency required by luxury apparel brands.