Injection moulds belong to a tool for producing plastic products. In order to meet the requirements of forming parts, we need to pay attention to some matters in selecting injection moulds and provide corresponding requirements. The following selection of more suitable injection mold needs to meet the six requirements.

       1. Many resin and additives of high corrosion resistance have corrosive action on the surface of the cavity. This corrosion makes the metal corrosion and peeling of the surface of the cavity surface, and the surface condition becomes bad and the quality of the plastic parts deteriorates. Therefore, it is better to use corrosion-resistant steel or chrome-plated, beryllium-nickel treatment on the surface of the cavity.

       2. good abrasion resistance, gloss on the surface of the injection molded parts and precision and injection mold cavity surface wear resistance has a direct relationship, especially some plastic adding glass fiber, inorganic filler and some paint, they and the plastic melt in the runner and cavity with high flow velocity, friction on the surface of cavity is very big, if material not wear-resisting, will soon wear and damage to parts quality.

       3.good dimensional stability during injection molding, injection mold cavity temperature to reach above 300 ℃. For this, it is best to choose the tool steel (heat treatment steel) which is treated with proper tempering. Otherwise, the change of the microstructure of the material will result in the change of the size of the injection mould.

      4.More than four, easy processing and mold parts for metal materials, some structure shape is complicated, in order to shorten the production cycle, improve efficiency, request mould material accuracy and is easy to be processed into the shape of the drawings required.

      5.polishing performance is good, injection molded parts usually require good gloss and surface state, so the cavity surface roughness is very small, so that the cavity surface must be surface processing, such as polishing, grinding, etc. Therefore, the selected steel should not contain coarse impurities and stomata.

      6. The influence of heat treatment is small in order to improve hardness and wear resistance. Generally, the injection mould should be treated with heat treatment, but this treatment should make its size change very small. Therefore, it is best to adopt pre-hardened steel that can be machined.