Mechanical Adjustment
Mechanical adjustment used to manage the dimensional stability of a fabric. Through web overfeed control, the machine feeds the fabric onto the pins at a faster rate than the chains are moving. This allows the fabric to relax and shrink in the length direction before it is heat set.
Excess Material
Small ripples are gathered into the web as it is pinned, which are then flattened by the drying heat. The percentage of web overfeed control applied depends on the previous stretching the fabric went through during dyeing or bleaching. Knitted fabrics usually require a higher setting than woven fabrics because the loop structure is more prone to elongation under tension.
Pinning Accuracy
Brushes or rollers press the fabric edge onto the stenter pins to secure the surplus length. If the web overfeed control is set too high, the fabric may sag or blow off the pins during the drying process. The synchronization between the feed rollers and the pin chain must be exact to ensure the overfeed is distributed uniformly along the entire length of the roll.
This mechanical alignment prevents uneven tension that would otherwise cause bowing or skewing in the final product.
Final Relaxation
Garment quality depends on the fabric reaching its natural dimensions during finishing. When web overfeed control is used correctly, the resulting fabric has low residual shrinkage and a better hand feel. If the fabric is finished under too much tension, it will shrink significantly during the first home laundry cycle.
