Shrinkage Calculation
A dimensional change occurs when the yarn shrinks or crimps as it is woven into a fabric and released from loom tension. The loom contraction describes the difference between the length of the warp yarn under tension and the final length of the woven fabric. This factor must be estimated to calculate yarn requirements, preventing shortages of material during production runs.
The calculation is restricted to the weaving phase and does not cover knitting shrinkage.
Tension Release
Calculating the contraction rate involves comparing the measured fabric length on the take-up roll with the length of the yarn fed from the beam. The degree of contraction depends on the yarn twist and the weave structure during weaving. A dense weave causes more contraction.
Weaving Margin
Loom technicians adjust the warp tension to control the contraction and ensure the fabric meets the specified length. If the contraction is too high, the fabric will be too short and too dense. The adjustment is made before starting bulk production.
Production Result
Spun yarns made from natural fibers show different contraction rates than synthetic filament yarns. This difference means that looms must be calibrated differently for each type of yarn to avoid yarn breakage. Understanding this mechanical behavior is essential for accurate cost estimation and production scheduling.
