Moulds have high requirements for materials, so the performance of mould materials should have the following points.
1. High wear resistance, if the mould is not wear-resistant, it is easy to cause excessive wear on the cavity.
2. High corrosion resistance, many plastic additives, such as flame retardants, and even the chemical action of the volume itself will corrode the mould cavity.
3. Good thermal conductivity. During injection moulding, good mould temperature control has a greater impact on the quality of plastic parts, especially when processing semi-crystalline thermoplastic parts. Generally, copper alloy has much better thermal conductivity than copper alloy steel, but its elastic modulus, hardness and durability are lower. The lack of thermal conductivity of steel can be compensated by a cooling system.
4. Good dimensional stability. During the moulding operation of the injection mould, the temperature of the cavity of the mould must reach more than 300 degrees. Such a large temperature difference is easy to cause microscopic changes in the cavity structure, so that the size of the mould changes, making the size of the plastic part unstable. .
5. Good polishing performance, high requirements for the inner wall of the mould cavity, and very small roughness to meet the requirements of good gloss on the plastic surface. For this, the mould cavity generally needs to be polished. The brighter the surface, the better. For this reason, The mould material is easy to polish, so the selected material should not have defects such as impurities and pores.