Determining Recovered Yarn Linear Density from Woven Fabrics
Determining recovered yarn linear density involves unraveling measured lengths, removing crimp under standardized tension, and correcting dry mass for size.
Dry Relaxed Length
Measured Length
The distance between two points on a yarn or fabric sample that has been allowed to contract naturally in a dry environment. Calculating the dry relaxed length provides a baseline for evaluating the shrinkage potential of knitted goods. This dimension represents the structure after mechanical stress is released but before exposure to moisture.
Dimensional Stability
Knitted loops undergo significant deformation during high-speed production on circular machines. The dry relaxed length shows how much the fabric returns to its natural state after sitting on a flat table. This recovery indicates the residual stress left in the yarn during knitting.
Laboratory Method
Testing requires the yarn to be placed in a standard laboratory environment with a relative humidity of sixty-five percent. This allows the dry relaxed length to be measured without the confounding effects of variable moisture. A precise environment ensures that results are reproducible across different testing facilities.
Factory Outcome
Finishers use this measurement to set the overfeed rolls on tentering machines to avoid excessive processing shrinkage. When the dry relaxed length is known, the target finished density can be achieved with minimal waste. This measurement helps garment factories prevent the shrinkage issues that often arise during domestic laundering.
Indeed, tracking this dimension before cut-and-sew operations ensures that the final apparel garments meet strict dimensional specifications after the first consumer wash.