In order to maintain the accuracy of plastic injection molds under injection pressure and clamping force, the feasibility of grinding, grinding and polishing the cavity parts must be considered when designing the mold structure. Although the processing of the plastic injection mold cavity and core has reached high precision requirements, and the shrinkage rate is the same as expected; However, due to the center offset during molding, the relevant dimensions of the inner and outer sides of the molded product are difficult to meet the design requirements of plastic parts. In order to maintain the dimensional accuracy of the front and rear mold cavities on the parting surface, in addition to setting the common guide pillar and guide sleeve centering, the positioning blocks such as conical positioning pin or wedge block must be added to ensure the accurate and reliable positioning of the plastic injection mold.
The material for making plastic injection molds should be high-quality alloy tool steel with high mechanical properties and low thermal creep. The mold material for making the cavity and runner should be selected through strict heat treatment with high hardness, good wear resistance, strong corrosion resistance, and thermal deformation resistance. At the same time, the difficulty and economy of mechanical processing and electrical processing should also be considered. In order to prevent the occurrence of aging changes and change the dimensional accuracy of plastic injection molds, it is necessary to specify tempering treatment or low temperature treatment to reduce the residual tissue of the heat treatment of the mold material when designing the mold.
For the vulnerable parts of the plastic injection mold, especially the vulnerable parts such as the cavity and core, the possibility of repair should be considered in the design to maintain the high accuracy of the mold after repair.