Woven Fabric Greige Sett Effects on Finishing Shrinkage Rates
Greige sett density determines yarn mobility and crimp capacity, directly establishing wet processing shrinkage and final finishing compaction limits.
Desizing Extraction Strain
Tension Influence
Mechanical stress applied to fabrics during the removal of sizing agents alters the dimensional properties of the raw material. This force, known as desizing extraction strain, occurs when the wet, heavy fabric is pulled through squeeze rollers to remove dissolved starches and polymers. Excessive tension at this stage can permanently deform the yarn structure before the final finish sets the fabric dimensions.
Process Impact
The action of desizing softens the yarn by removing the protective coating that was applied before loom construction. As a result, the fabric becomes highly vulnerable to stretching and elongation under tension. When the wet web undergoes desizing extraction strain, the warp crimp is pulled out, which increases the fabric length while reducing the width.
This structural change complicates subsequent tentering and finishing operations.
Control Strategy
Modern processing ranges utilize load cells and variable speed drives to maintain low, uniform tension throughout the wash boxes. Minimizing the strain prevents fabric distortion and reduces the risk of edge curling in knit or lightweight fabrics.
Quality Evaluation
Technicians measure fabric yield and width after desizing to ensure the material remains within specifications. Out-of-spec dimensions indicate that the extraction tension was too high, requiring adjustment of the drive motors.