(3) Mold accuracy, that is, avoiding cards, fine positioning, guide posts, positioning pins, etc. The positioning system is related to the appearance quality of the product, the quality and life of the mold. According to the different mold structure, different positioning methods are selected, and the positioning precision control mainly depends on the processing. The internal model positioning is mainly designed by the designer to design a more reasonable and easy to adjust positioning method.
(4) The gating system, that is, the feeding passage from the nozzle of the injection molding machine to the cavity, including the main flow path, the split flow path, the gate and the cold material hole. In particular, the location of the gate should be such that the molten plastic fills the cavity under good flow conditions, and the solid flow channel and gate cold material attached to the article are easily ejected from the mold and removed during mold opening. (except for hot runner molds).
(5) Plastic shrinkage and various factors affecting the dimensional accuracy of the product, such as mold manufacturing and assembly errors, mold wear, etc. In addition, when designing compression molding and injection molding, the matching of the process and structural parameters of the molding machine should also be considered. Computer-aided design techniques have been widely used in plastic mold design.