Determining Flax Fibre Fineness and Area Distribution Parameters
Flax fibre fineness and area distribution parameters govern wet-spinning limits, bundle drafting cohesion, hackling yield, and yarn tenacity.
Sliver Linear Mass Variance
Drafting Evaluation
Sliver linear mass variance governs the uneven distribution of mass along the carded flax ribbon before drafting frames draw the fibers into a continuous strand for spinning. Chinese mills measure this irregularity on capacitance testers during the preparatory passage from the gill box to the speed frame, recording the coefficient of variation on the production lot sheet. High variation causes weak spots in the yarn, forcing operators to adjust roller settings on the draw frame to maintain uniform tension.
Batch Variance
Fiber thickness anomalies in flax lots propagate directly into the drafted sliver, producing heavy sections that jam the ring frame and light sections that break under sudden load. Mill supervisors compare these inline test readouts against buyer acceptance criteria specified in the export contract rather than relying on internal mill grades alone. Drafting heads compensate for incoming density fluctuations by altering the speed differential between the front and back rollers, reducing mass irregularity before roving commences.
Specification Limits
Acceptance thresholds for linear mass variation dictate whether a flax sliver batch proceeds to the wet spinning department or returns to the blending floor for reprocessing. Exceeding the contractual irregularity ceiling triggers a penalty on the finished linen yarn price, altering the export margin for the mill. Quality control records store these variance measurements as definitive proof of compliance with international flax processing standards.