Fiber Recovery
The time required for a stretched textile fiber to return to its original length after the tension is removed determines its behavior during high-speed weaving. In linen yarns, the elasticity relaxation time is relatively long due to the highly crystalline structure of the natural flax fibers. This slow recovery means that yarns do not immediately contract after being stretched by the shedding action of the loom.
Laboratorians measure this property by conducting tensile recovery tests on wet and dry spun yarns.
Tension Balance
When the yarn undergoes rapid cyclic elongation, a slow relaxation rate causes the warp sheet to remain loose for a brief period after the shed closes. If the elasticity relaxation time is longer than the loom’s cycle time, the warp line will lack the tension required for a clean beat-up. This lag leads to a loose fabric structure and can cause weft yarn displacement during weaving.
Operators must adjust the loom speed and tension settings to match the relaxation behavior of the specific flax yarn batch being processed, with each test result filed in the fiber quality certificate.
Fabric Density
Slow-relaxing yarns can cause uneven pick spacing and reduced fabric density if the weaving cycle is too fast. This behavior is documented in the yarn specification sheet provided by the spinner. Checking this parameter prevents the production of slack-woven fabrics.
