Spinning Specification
Sliver weight consistency dictates the quality of the output produced during the initial stage of mechanical flax processing. The main draft represents the ratio of input linear density to output linear density across the primary drawing frame. Mill operators set this value to reduce the mass per unit length of the sliver, aligning the fibre geometry for subsequent spinning.
Higher ratios increase the extension of the material while lower ratios maintain fibre orientation. This numerical parameter remains the primary control for ensuring uniformity in the finished yarn.
Acceptance Criteria
Quality managers verify these settings against the internal technical dossier of the production facility. Deviation from the target main draft creates irregularities in the diameter of the roving, causing faults that remain present through the final weaving operation. Fabric producers define maximum allowable variation for this value in their purchase agreements to ensure consistent hand and durability in the end product.
Any variance outside of the mill tolerance necessitates an immediate adjustment to the drafting rollers.
Mechanical Constraint
Physical limitations of the drawing machinery determine the upper boundary of the reduction possible in one pass. Fibre length distribution constrains the maximum spacing between the front and back rollers, forcing a compromise between the total attenuation and the mechanical integrity of the sliver. Excessive tension during the process causes breakage, while insufficient drafting leads to thick and thin spots known as slubs.
Controlled reduction prevents long-term fibre degradation during the high-speed transit of the drawing cycle. Proper calibration of these mechanical components ensures the tensile strength of the resulting flax product remains within industrial standards.
