The shrinkage of plastics is mainly due to the shrinkage of the volume, the surface raw materials at the thickness of the wall are pulled in, and dent marks appear on the surface of the finished product during chemical conversion. Shrinkage is the most common undesirable phenomenon that occurs on the surface of the finished product. It mostly occurs at the thickness of the wall. Generally, if the pressure drops, the chance of shrinkage will be greater.
1. In the aspect of plastic injection molding, increase the injection pressure and hold the mold pressure after the injection is completed, and give sufficient cooling time;
2. In the aspect of plastic mold, the mold cooling water circuit design is unreasonable, and the mold needs to be modified;
3. The product structure is due to the product If the thickness of the product is uneven, the thick part of the product is difficult to cool. The outer surface is cooled, but the inside may still be molten, so the structure design of the product must be changed.