Gravimetric Verification Protocols for Flax Line Fibre Linear Density
Conditioned middle-cut bundle weighing under ISO 2370 delivers precise flax line fibre linear density data for wet-spinning count calculations.
Hackling Yield Percentage
Fiber Ratio
Hackling yield percentage is a primary metric of material recovery during the preparatory drawing stage inside Chinese linen mills. The calculation determines the proportion of long line flax fibres retained for spinning after the removal of short tow waste. Mill operators weigh incoming bales of scutched flax before the material enters the mechanical combing drums, comparing that initial mass against the output of straightened parallel strands exiting the final combing pins.
Lower grades of flax typically generate excessive tow proportions because the natural reed structure contains weak nodes that fracture under high mechanical tension. Buyers stipulate minimum yield thresholds within supply contracts to ensure that incoming lots possess sufficient tensile strength for fine yarn production. Factory floor managers record these throughput masses inside daily production ledgers, creating an auditable paper trail that connects raw material purchases directly to subsequent spinning efficiency.
Combing Efficiency
Mechanical adjustment of the hackling pins dictates the speed at which short fibres separate from the continuous ribbon of flax. Tighter pin settings remove unwanted debris and short fragments effectively, but aggressive adjustment increases fibre breakage and reduces overall yield. Technicians calibrate the combing drums by inspecting sample handfuls drawn from the output chute every four hours.
When humidity levels inside the mill drop below standard thresholds, the dry flax becomes brittle and shatters upon impact with the rotating pins, driving yield downward regardless of machine calibration. Mill supervisors balance pin density against raw material quality to prevent excessive waste generation while maintaining adequate cleanliness standards for wet spinning preparation.
Quality Threshold
Commercial agreements divide output into distinct categories where a mill standard differs significantly from buyer acceptance criteria. Internal mill targets focus on maximizing material throughput to control operating costs, whereas customer specifications prioritize yarn regularity and minimum staple length over raw conversion efficiency. Exporters test finished woven cloth against international grading standards that penalize irregular yarn diameters caused by excessive tow contamination in the parent sliver.
Batches failing the required threshold undergo secondary processing or downgrade to coarser yarn counts used for industrial canvas rather than apparel fabrics. Final export documents record the confirmed grade classification alongside the initial hackling yield percentage to verify that manufacturing parameters matched the agreed commercial specification throughout the production cycle.