Thickness Consistency
Variations in the mass per unit length of spun linen yarn are measured to assess the consistency of the spinning process. This yarn count variation determines the quality grade of the finished linen fabric and its suitability for high-end garments or industrial textiles. High variation leads to a streaky appearance in the woven cloth and reduces its mechanical strength.
Roller Uniformity
Mechanical wear on the drafting rollers or incorrect roller settings can introduce periodic thickness variations into the yarn. When the pressure on the wet spinning drafting rollers is uneven, the flax fibres are not drawn out at a constant rate, which directly increases the yarn count variation. This issue is often compounded by fluctuations in the moisture content of the roving, as wet fibres draft differently than dry ones.
Regular calibration of the drafting roller pressure and maintenance of the water temperature in the wetting bath are necessary to keep the variation within the limits specified by the buyer. Spun yarns with low variation command a premium price on the international textile market.
Fabric Appearance
Weaving efficiency and fabric hand are directly influenced by the uniformity of the yarn. High yarn count variation increases the frequency of thread breakages during the high-speed weaving process, which reduces loom efficiency and increases production costs. In the finished fabric, these thick and thin sections create a highly uneven surface texture that can cause dye streaks during the final finishing stage.
