1) Variety of plastic
Various plastics have their own shrinkage ranges, but even if the same plastic has different molecular weights, fillers, and proportions, the shrinkage and anisotropy are different.

2) Plastic parts structure. Shape, size, wall thickness, presence or absence of inserts, number and layout of inserts, etc.
Generally, the greater the wall thickness of a plastic part, the greater the shrinkage rate. The plastic part with a complex shape has a smaller shrinkage rate than the plastic part with a simple shape. Plastic parts with inserts will reduce the shrinkage due to the obstruction of the inserts and chilling.

3) Injection mold structure
4) Injection mold forming process conditions

www.xlpmould.net