Dimensional Reduction
Permanent changes in length or width occur when a fabric is subjected to heat and mechanical agitation during the final stages of production. Manufacturers monitor finishing shrinkage to ensure that the fabric delivered to the garment factory remains stable through subsequent processing. This change is distinct from the shrinkage that occurs during consumer laundering.
Thermal Setting
Synthetic fibres often require high temperatures to lock their molecular structure into a specific shape. If the temperature used during this stage is insufficient, finishing shrinkage will be high when the material is later exposed to steam or pressing. Proper dwell time in the heatsetting oven minimizes these variations by allowing the polymers to reach a relaxed state at the desired dimensions.
When the cooling process is too rapid, it can trap residual stresses that later cause the fabric to contract unexpectedly.
Width Management
Tension applied by the stenter pins holds the fabric at a specific width while it dries. This mechanical constraint counteracts the natural tendency of the yarns to contract, but some finishing shrinkage is inevitable once the cloth is removed from the machine.
Specification Compliance
Buyers set strict tolerances for these dimensional changes to avoid fit issues in the final apparel. Accurate measurement of finishing shrinkage allows the mill to adjust the initial weaving or knitting parameters to compensate for the expected loss in area.
