Mechanical Adjustment
Differential speed regulation between the feeding roller and the pin chain in a stenter frame controls the relaxation and dimensional stability of finished fabrics. The overfeed ratio determines the percentage of extra fabric length fed into the machine compared to the speed of the transport chain. This adjustment allows the fabric to shrink and relax in the warp direction, reducing residual shrinkage in the finished garment.
Process Application
Knit fabrics are highly prone to stretching during wet processing and require tensionless drying to restore their natural loop geometry. Setting a positive overfeed ratio ensures that the loops can relax and shorten during the heat-setting phase. This control prevents the fabric from shrinking excessively when it is washed by the end consumer.
Quality Output
Controlling the warp shrinkage of the fabric ensures that the finished garments do not change shape or size after laundering. When the overfeed ratio is optimized, the fabric achieves a higher weight per square meter and a softer hand feel. This treatment is verified by measuring the dimensional stability of the fabric before it is sent to the cutting room.
Process Boundary
A negative ratio is occasionally used for stretching fabrics to a wider width. This step increases fabric tension.