Yarn Tensile Testing
category
Yarn tensile testing measures breaking force, tenacity, elongation-at-break, and work-to-break of single yarn ends using constant rate of extension (CRE) tensile testers at standardised gauge lengths and extension rates, providing data for warp acceptance testing, process optimisation, and end-use specification compliance. ISO 2062 (single thread method): gauge length 500 mm for staple yarn, 250 mm for filament, extension rate 500 mm/min producing break time 20 ±3 seconds — 20 minimum tests per direction (warp, weft) for statistical validity. Textechno Statimat 4U (automated 500 m/min test speed, 300 tests/hour, Uster Tensorapid 4 to 5,000 tests/hour for high-volume mill quality control) versus manual single-end tensile testers for laboratory use. Tenacity calculation: cN/tex = breaking force (cN) / linear density (tex) — USTER Statistics 2023 Ne 30 ring-spun cotton benchmarks: 5th percentile 21.8 cN/tex (export quality), 50th percentile 18.2 cN/tex (average mill), 95th percentile 14.5 cN/tex (below-average). Elongation-at-break benchmarks: ring cotton Ne 30: 50th percentile 6.8%, 5th percentile 8.5% (higher elongation = better); rotor Ne 20: 50th percentile 7.2%. Work to break (specific work of rupture, cN·cm/tex): energy absorbed to yarn failure — warp yarn minimum 8 cN·cm/tex for weaving application. Wet tenacity ratio (wet/dry): cotton 1.05–1.10 (strengthens), viscose 0.40–0.60 (weakens 40–60% when wet — critical for viscose warp weaving requiring yarn oiling or size application).
Role
Yarn tensile testing is the primary mechanical acceptance test for warp yarn in weaving mills — tenacity and elongation directly determine loom warp breakage rate, with each 1 cN/tex tenacity improvement at Ne 30 cotton corresponding to approximately 8–12% reduction in warp ends down per loom per hour, the most direct economic quality parameter for weaving productivity optimisation.