Fibre Regularity
The mass variation per unit length in a textile strand determines the performance grade of flax yarn exiting spinning frames in Hebei mills. Yarn unevenness measures the short-term and long-term mass deviations along the continuous strand, originating from drafting irregularities in the drawing frame and fibre length variations in the raw flax supply. Capacitance testers evaluate the moving material by passing the strand between two condenser plates, where dielectric changes translate directly into linear density fluctuations.
Chinese export standards classify the resulting mass variation coefficient into distinct percentile tiers that separate low-grade weaving yarns from premium warp yarns destined for European markets.
Masa Variance
Modern capacitance meters record continuous mass fluctuations and compute the coefficient of mass variation, which serves as the primary metric for internal mill quality control before final bale packaging. High irregularity values indicate inadequate draft roller pressure or slippage in the roving frame, causing localized thick and thin spots that weaken the woven fabric during subsequent sizing and loom operations. Quality inspectors compare these recorded sensor outputs against the mill technical dossier to determine if the batch satisfies the contractual tolerance limits established by the buyer.
Grade Threshold
Commercial textile contracts establish strict upper limits for mass deviation, and any yarn batch exceeding these contractual thresholds fails the finishing inspection before dyeing and export clearance. Mill operators adjust drafting zones and pin densities in the preparatory gill box to reduce mass variation, thereby preventing structural defects in the final woven linen fabric. Technical supervisors record these corrective adjustments in the production log to maintain traceability from the raw flax bale to the finished export consignment.
