1. There are four cases of plastic shrinkage: heat shrinkage, phase change shrinkage, orientation shrinkage, compression shrinkage, and elastic recovery. The shrinking process consists of three parts: shrinkage before the gate solidifies, cooling shrinkage, and shrinkage after demolding.
2. The main reasons for shrinkage: 1, insufficient injection volume 2, melt temperature is too high 3, injection pressure and holding pressure is too small 4, injection time and holding time too little 5, injection speed is too large 6 mold temperature is improper
3. The main reasons for shrinkage: 1, the injection volume is not enough 2, the injection pressure is too low 3, the injection speed is improper 4, the mold temperature is too low.