Injection molds generally need to work in a high-temperature environment of 150° to 200° when manufacturing plastic products in injection molding machines. Therefore, the selection of raw materials in the process of manufacturing injection molds requires great attention, which will be overall for the later period. The service life of the injection mold and the quality of the plastic product produced to play a crucial role in determining the performance requirements of the injection mold steel.
1, Mold steel requires sufficient surface hardness and wear resistance
The hardness of the injection mold is usually below 50-60HRC, and the heat-treated mold should have sufficient
surface hardness to ensure the mold has sufficient rigidity. In the work, the mold is subjected to large compressive stress and friction due to the filling and flow of the injection molding. It is required that the mold maintains the
accuracy of the shape and the dimensional accuracy to ensure the mold has a sufficient service life. The wear resistance of the mold depends on the chemical composition of the steel and the heat treatment hardness, so enhancing the hardness of the mold is beneficial to enhance its wear resistance.
2, excellent machinability
Most injection moldings Die to require a certain amount of cutting and fitter repair in addition to EMD processing. In
order to prolong the service life of the cutting tool, enhance the cutting performance and reduce the surface
roughness, the hardness of the steel for the injection mold must be appropriate.
3, good thermal stability
The shape of the injection mold is often complicated, and it is difficult to process after quenching. Therefore, it should be selected with good thermal stability. When the two-color mold is processed, the coefficient of linear expansion is small, the heat treatment deformation is small, and the temperature difference is caused. The rate of change is small, the metallographic structure and the mold size are stable, and the processing can be reduced or no longer processed to ensure the dimensional accuracy and surface roughness of the mold.
4, good polishing performance
High-quality two-color injection molded products require a small roughness value on the surface of the cavity. For example, the surface roughness value
of the injection molding cavity is required to be less than Ra 0.1 to 0.25, and the optical surface is required to be Ra < 0.01 nm. The cavity must be
polished to reduce the surface roughness value. The steel material selected for this purpose requires fewer material impurities, fine uniformity of the structure, no fiber orientation, and no pitting or orange peel defects during polishing.