Woody Impurity
Vegetable residue measurement quantifies the proportion of bark and pith remaining in flax fibres after mechanical processing. Shive area fraction represents the ratio of total surface area covered by these particulate inclusions to the overall area of the fibre sample. Technicians determine this value during the scutched flax evaluation stage.
Labs often employ optical scanning devices to calculate the distribution of these small, rigid fragments against a standardized white background. This metric provides a objective benchmark for determining the efficacy of decortication lines. Lower values indicate superior extraction performance.
Production Parameter
Procurement officers verify this value in the technical dossier for exported flax bales to confirm compliance with mill specifications. During the spinning phase, high particle counts result in frequent yarn breakage and inconsistent diameter in the finished thread. Quality control supervisors check the shive area fraction against the buyer acceptance criteria set for specific yarn counts.
Heavy particles often remain trapped within the fibre bundle through the heckling process. Excessive amounts force the mill to increase waste extraction rates which lowers overall yield.
Acceptance Criteria
Commercial contracts for raw linen materials define specific thresholds for permissible residual matter. Buyers distinguish between fibre grades based on the calculated density of woody inclusions per square decimetre of the web. This standard differentiates premium grade long line flax from tow grades by establishing a maximum allowable impurity limit.
High levels of contamination increase the cost of downstream chemical finishing and bleaching processes. Precise monitoring of this fraction ensures consistent production quality throughout the entire manufacturing cycle.
