Second, the material selection of plastic molds
1. Therefore, under the premise of satisfying the use performance, the first choice is to choose the lowest carbon steel, no alloy steel is used, and no imported materials are used if domestic materials can be used. In addition, the production and production of the market should also be considered when selecting materials, and the selected steel grades should be as small and concentrated as possible, easy to buy.
2. With the expansion of the use of plastic products, inorganic materials such as glass fiber are often added to the plastic to enhance the plasticity, due to the addition of additives, the fluidity of the plastic is greatly reduced, resulting in the wear of the mold, so it is required to have good wear resistance.
3. It is usually used for a large number of plastic products, such as mirror mold processing, and the hardness range used is 3 40HRC. Material selection for plastic molds requires 1. Good polishing performance, high-quality injection molded products require a small cavity surface roughness.
4. For the manufacture of complex, precise and corrosion-resistant plastic molds, pre-hardened steel (such as PMS), corrosion-resistant steel (such as PCR) and low-carbon martensitic aging steel (such as 18Ni-25) can be used, all of which have better cutting, heat treatment and polishing properties and higher strength.
5. When the wear-resistant blank is plastically denatured in the mold cavity, it flows and slides along the cavity surface, which causes severe friction between the cavity surface and the blank, resulting in the failure of the mold due to wear. Therefore, the wear resistance of the material is one of the more basic and important properties of the mold. Hardness is a major factor affecting wear resistance.
6. Plastic mold materials can be divided into the following six categories according to different characteristics: pre-hardened By adding sulfur, calcium, lead, selenium and other elements to the steel, the cutting performance of pre-hardened plastic mold steel can be effectively improved.