What performance requirements need to be met when selecting steel for injection mold processing?
Injection mold processing in the injection molding machine production of plastic products generally need to work in a high temperature environment of 150 degrees Celsius to two hundred degrees Celsius, so in the process of manufacturing injection molds the selection of raw materials need to pay great attention, which will play a vital role in the overall injection mold service life and the quality of plastic products produced, so Jiangyin injection mold processing in the selection of injection mold steel raw materials need to meet what performance requirements?
First, sufficient surface hardness and wear resistance
The hardness of injection mold processing is usually below 50-60HRC, and the heat-treated mold should have sufficient surface hardness to ensure that the mold has sufficient rigidity. The mold is required to maintain the stability of shape accuracy and dimensional accuracy due to the filling and flow of injection molding in the work, and ensure that the mold has sufficient service life. The wear resistance of the mold depends on the chemical composition of the steel and the hardness of the heat treatment, so enhancing the hardness of the mold is conducive to enhancing its wear resistance.
Second, excellent machinability
Most injection molding molds, in addition to EMD processing, also need to carry out certain cutting processing and fitter repair. In order to extend the service life of cutting tools, enhance cutting performance, and reduce surface roughness, the hardness of steel for injection molds must be appropriate.
Third, 50 grades of carbon steel have certain strength and wear resistance, and are mostly used for mold base materials after quenching and tempering treatment. High-carbon tool steel and low-alloy tool steel have high strength and wear resistance after heat treatment, and are mostly used for forming parts. However, high-carbon tool steels are only suitable for manufacturing molded parts with small dimensions and simple shapes due to their large heat treatment deformation.
4. Good thermal stability
The shape of the parts processed by injection mold is often more complex, difficult to process after quenching, so it should be selected as much as possible with good thermal stability, when the two-color mold molding processing after heat treatment due to the small coefficient of linear expansion, heat treatment deformation is small, the size change rate caused by temperature difference is small, metallographic structure and mold size stability, can be reduced or no longer processed, can ensure mold dimensional accuracy and surface roughness requirements.
5. Good polishing performance
High-quality two-color injection molding products require small roughness values on the cavity surface. For example, the surface roughness value of the injection molding model cavity is required to be less than the level of Ra0.1~0.25, and the optical surface is required to be Ra<0.01nm, and the cavity must be polished to reduce the surface roughness value. The steel selected for this purpose requires less material impurities, fine and uniform structure, no fiber directionality, and no pockmarks or orange peel-like defects during polishing.