Woven Fabric Weight Tolerances and Linear Metre Yield Calculations
Reconcile woven fabric purchases by calculating linear yield from conditioned mass and usable cuttable width under ISO 3801 and ISO 139 parameters.
Overfeed Percentage
Tension Control Metric
Operational settings in fabric finishing machinery determine the ratio of fabric speed entering the machine compared to the speed of the transport chain. The overfeed percentage describes the intentional slack introduced during processes like stentering to control the final dimensions and shrinkage of the cloth. It is calculated by comparing the input velocity to the output velocity.
This technique allows the fabric to relax and shrink in the longitudinal direction while it is being dried or heat-set.
Dimensional Stability
Proper application of this setting is necessary to ensure the finished garment does not shrink excessively when washed by the consumer. By feeding more fabric into the machine than the chains pull out, the manufacturer forces the yarns to crowd closer together. This overfeed percentage counteracts the tension applied during weaving and dyeing, which tends to stretch the fabric.
If the setting is too low, the fabric remains under tension and will shrink as soon as it is wetted. If it is too high, the fabric may become too heavy or develop surface ripples.
Machinery Operation
Modern stenter frames use electronic sensors to maintain a precise level of slack across the entire production run. The operator sets the value based on the fabric type and the results of previous shrinkage tests. For a heavy denim, a high percentage might be needed to achieve the desired weight and stability.
A lightweight voile requires a much lower setting to avoid distorting the delicate weave. Constant monitoring ensures that the overfeed percentage stays within the specified range, preventing variances between the beginning and the end of a fabric roll.
Performance Verification
Quality inspectors check the finished fabric for weight and residual shrinkage to confirm the settings were correct. If the fabric fails these tests, the finishing process may need to be repeated. Accurate control of this metric is essential for producing high-quality, stable textiles.
It directly impacts the final fit of the garment.
Yarn Linear Density and Crimp Factor Controls on Mass per Unit Area
Fabric mass per unit area is calculated by combining yarn linear density, thread count, and crimp factors across conditioned warp and weft system dimensions.