Differential Speed
Mechanical speed differential controls on stenter finishing frames feed wet or un-set fabric onto pin chains faster than the chain conveyance speed. Adjusting overfeed setting allows warp yarns to relax and crimp, increasing fabric weight per unit area while pre-shrinking the fabric during heat treatment. The setting governs longitudinal fabric compression during drying, excluding lateral width adjustments managed through pin chain rail widening.
Warp Relaxation
Feed rollers driven by independent variable-speed motors introduce fabric onto stenter pin chains at controlled positive ratios. A higher overfeed setting ranging from ten to thirty percent creates micro-waves of slack fabric between pins, permitting thermal shrinkage inside heat-setting chambers. Steam injection zones soften natural or synthetic fibers, enabling rapid relief of internal tensions introduced during weaving or knitting.
Machine operators calibrate feed ratios against incoming fabric speed to achieve specified weight targets. Real-time length counters verify total shrinkage allowance across the finish run.
Density Control
Insufficient overfeed leaves residual warp tension inside finished fabric rolls. High internal tension causes severe garment shrinkage during home laundering.
Dimensional Stability
Finishing mills adjust feeder speed ratios to meet buyer specifications for residual wash shrinkage. Correct calibration of overfeed setting guarantees dimensional stability and correct fabric density prior to garment cutting.
