What are the general requirements for steel for plastic mold manufacturing? With regard to the requirements for the manufacture of plastic molds, today, Nodi will introduce to you here:
When pressing plastics, it can be divided into two types of substrates, one is a thermosetting plastic and the other is a thermoplastic.
Precision plastic mould
Thermosetting plastics such as bakelite powder are pressed and permanently formed under heat and pressure. The bauxwood mold is periodically subjected to pressure and is continuously heated at a temperature of 150 to 200 °C.
Thermoplastics, such as polyvinyl chloride, are generally selected by injection molding. The plastic is heated in a separate heating chamber and then injected into a colder mold in a softened state to apply pressure to form a cold-hardened mold.
The normal operating temperature of the injection mold is 120~180 °C, and it is also up to 260 °C. However, water is usually used to cool the cavity during operation, so it is less affected by heat, stress and wear. Only some varieties, such as plastics containing chlorine and fluorine, precipitate harmful gases during pressing, which has a great erosion effect on the cavity.
According to the working conditions and characteristics of precision plastic molds, the following requirements are imposed on steel for plastic molds:
1 steel material needs to be very pure to obtain a highly lustrous processed surface. For this reason, less inclusions, less segregation, dense structure and high surface hardness are required;
2 The surface should be wear-resistant and resistive. It is required to have a certain surface hardening layer. Generally, it should be above 45hrc, and the surface finish should remain unchanged for a long time;
3 has sufficient strength and toughness to withstand the load without deformation or damage;
4 heat treatment deformation is small to ensure interchangeability and matching accuracy;
5 has good electrical processing capabilities.