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.
Yarn Straightening
Crimp Removal
The application of a specific tensile load to a yarn sample removes its structural curl or crimp without stretching the underlying fibers. Performing yarn straightening is a necessary step before measuring the twist or the true length of a textured yarn. This load must be carefully calibrated to avoid drafting the fiber.
Measurement Utility
Measuring a yarn in its curled state produces inaccurate results due to the variable bulk of the texturizing process. The yarn straightening procedure establishes a consistent baseline length that can be compared across different production lots. This ensures that the yarn meets the physical dimensions specified in the contract.
Tension Method
This action is performed by hanging a pre-determined weight on the yarn or using an automated tensile tester. The amount of tension used for yarn straightening depends on the linear density of the yarn being tested. This process must be executed under standard atmospheric conditions to maintain fiber elasticity.
Knitting Calibration
Garment factories utilize this measurement to ensure that the yarn has the correct loop-forming properties on the knitting machine. When yarn straightening is done correctly, the yarn behaves predictably during high-speed knitting operations. This prevents the formation of streaks or holes in the finished apparel fabric and results in a highly uniform garment surface that meets commercial grade requirements.