Sizing

Sizing is the process of applying a protective coating (size) to warp yarns to improve their weavability. The size forms a film around the yarn, reducing friction and preventing breakage during weaving. Common sizing materials include starch, PVA, CMC, and acrylic polymers.

Size pick-up % indicates the amount of size added relative to the unsized yarn weight. Typical pick-up ranges from 5-25% depending on yarn count and fabric type. Stretch % must be carefully controlled (typically 0.5-2%) to maintain yarn elasticity. Invisible loss accounts for size material lost during processing through evaporation, spillage, and residual liquor. Moisture content after sizing should be 6-10% for optimum weaving performance. Maximum machine speed is limited by the drying capacity of the cylinders.