Weft Yarn Specifications
topic
Weft yarn requires primarily: good elongation (5–8%, higher than warp to withstand pick insertion shock), low twist multiplier (3.0–4.0 for soft handle), low hairiness for clean shed in air-jet weaving (S3 <2 for high-speed air-jet), and controlled package hardness for even unwinding. Tenacity requirement is lower than warp (>12 cN/tex Ne 30). Weft count variation causes horizontal banding (weft barre) — the most visible fabric defect in plain-weave fabrics.
Role
Weft yarn specification knowledge is critical because weft quality faults have a disproportionate visual impact on fabric appearance. Weft barre from count variation is the number-one reason for fabric grading from A to B grade, immediately reducing fabric value by 15–25%. Understanding weft quality requirements and how to control them in ring spinning directly impacts a mill's fabric quality grading and revenue.