In the mould manufacturing, mould selection is a very important part of the entire mould manufacturing process.
The precision of die machining is high. The auxiliary mouldis generally composed of a concave mold, a convex mouldand a mouldframe, and some may also be a multi-piece assembly module. Therefore, the combination of the upper and lower molds, the combination of the insert block and the cavity, and the combination between the modules require high processing accuracy. The dimensional accuracy of precision molds often reaches the?m level.
The selection of materials for the mouldneeds to meet three principles. The mould meets the work requirements of wear resistance and toughness. The mould meets the process requirements. At the same time, the mouldshould meet the economic applicability.
1. Wear resistance
When the blank is plastically deformed in the mouldcavity, it flows and slides along the surface of the cavity, which causes intense friction between the surface of the cavity and the blank, resulting in the failure of the moulddue to wear. Therefore, the wear resistance of the material is one of the most basic and important properties of the mold.
Hardness is the main factor affecting wear resistance. In general, the higher the hardness of the mouldparts, the smaller the amount of wear and the better the wear resistance. In addition, wear resistance is also related to the type, number, form, size and distribution of carbides in the material.
2. Strong toughness
Most of the working conditions of the mouldare very bad, and some often bear a large impact load, which leads to brittle fracture. In order to prevent the mouldparts from being brittlely broken at work, the mould should have high strength and toughness.
The toughness of the mouldmainly depends on the carbon content, grain size and microstructure of the material.