Injection moulds are a kind of tool for producing plast […]
Injection moulds are a kind of tool for producing plastic products. In order to meet the needs of moulded parts, we need to pay attention to some matters when selecting injection moulds, and put forward corresponding requirements.
1. High Corrosion Resistance Many resins and additives have corrosive effects on the surface of the cavity. This corrosion causes the surface of the cavity to corrode and peel off, the surface condition deteriorates, and the quality of the moulded part deteriorates. Therefore, use corrosion-resistant steel, or chrome-plated, nickel-plated surface of the cavity.
2. good wear resistance, the gloss and precision of the surface of the injection moulded plastic parts are directly related to the wear resistance of the cavity surface of the injection mould, especially when some plastics add glass fiber, inorganic filler and some pigments, they Together with the plastic melt, it flows at idle speed in the flow channel and the cavity. The friction on the surface of the cavity is very large. If the material is not wear-resistant, it will wear quickly and the quality of the plastic part will be damaged.
3. good dimensional stability In the injection moulding, the temperature of the injection mould cavity should reach more than 300 °C. For this purpose, tool steel (heat treated steel) treated with appropriate tempering is used. Otherwise, it will cause a change in the microstructure of the material, resulting in a change in the size of the injection mould.
4. easy to process mould parts are mostly made of metal materials, and some structural shapes are still very complex, in order to shorten the production cycle, improve efficiency, mould materials are required to be easily processed into the shape and precision required by the drawings.
5. good polishing performance Injection moulding plastic parts are usually required to have a good gloss and surface state, so the surface roughness of the cavity is required to be very small, so the surface of the cavity must be surface processing, such as polishing, grinding and so on. Therefore, the selected steel should not contain rough impurities and pores.
6. Small effect by heat treatment In order to improve hardness and wear resistance, it is generally necessary to heat-treat the injection mould, but this treatment should make the dimensional change small. Therefore, * pre-hardened steel that can be machined is used.