1. High corrosion resistance: Many resins and additives have a corrosive effect on the surface of the cavity. This corrosion causes the metal on the surface of the cavity to be corroded and peeled off, the surface condition becomes worse, and the quality of the plastic parts deteriorates. Therefore, it is best to use corrosion-resistant steel, or chromium plating, cymbal nickel treatment on the cavity surface.
2. Good wear resistance: The gloss and precision of the surface of plastic parts are directly related to the wear resistance of the surface of the injection moulding service cavity, especially when GF, inorganic fillers and certain pigments are added to some plastics. The melt flows at high speed in the runner and the injection moulding cavity together, and the friction on the surface of the cavity is great. If the material is not wear-resistant, it will wear out quickly, which will damage the quality of the plastic part.
3. Good dimensional stability: During plastic molding, the temperature of the injection mould cavity must reach above 300°C. For this reason, it is best to select tool steel (heat-treated steel) that has been properly tempered. Otherwise, the microstructure of the material will change, which will cause the size of the injection moulding to change.
4. Easy to process: Most of the injection moulding service parts are made of metal materials, and some structural shapes are still very complicated. In order to shorten the production cycle and improve efficiency, the injection moulding service materials are required to be easy to process into the shape and accuracy required by the drawings.
5. Good polishing performance: plastic parts are usually required to have good gloss and surface condition, so the roughness of the cavity surface is required to be very small. In this way, the surface of the cavity must be surface processed, such as polishing and grinding. Therefore, the selected steel should not contain rough impurities and pores.
6. Less affected by heat treatment: In order to improve the hardness and wear resistance, the injection moulding is generally heat treated, but this treatment should make the size change small. Therefore, it is best to use pre-hardened steel that can be cut.