Mechanical Resistance
Mechanical forces within the secondary cell wall determine how flax fibres withstand the aggressive scraping during the scutching process. The mechanical resistance known as cell wall shear strength governs whether the bast tissue splits cleanly into fine bundles or breaks into waste tow. During the primary extraction stage at the Chinese processing mill, technicians measure the shear resilience of flax stems to generate the scutching efficiency report.
Processing Threshold
Fibre bundles with insufficient shear strength fracture under the metal blades of the scutching turbine, causing excessive production of low-value short fibres. High cell wall shear strength ensures that the long line fibres remain intact and straight during extraction. This characteristic acts as a primary metric for determining the spinning potential of the raw flax shipment.
Quality Standard
Mill operators compare the mechanical test results against the buyer’s acceptance criteria to assign the final raw fibre grade before spinning begins. While the mill’s internal standard prioritises high yield of long fibres, the purchasing agreement specifies a narrow range of cell wall shear strength to prevent yarn unevenness during subsequent drawing operations. The final inspection certificate lists this parameter alongside moisture content and average fibre length.
This document provides the spinning mill with a reliable predictor of draft performance across the drawing frames.
