There are many requirements for the materials on the automotive plastic part. Today we will understand the requirements of the automotive plastic part.
have sufficient surface hardness and wear resistance: the general hardness of automotive plastic parts is usually below 50-60HRC, and the mold should have sufficient surface hardness after heat treatment to ensure that the mold has sufficient rigidity. When the mold is in operation, the filled and movable plastics receive greater compression stress and friction, and the mold is required to maintain the accuracy of its shape and the stability of the dimensional accuracy to ensure that the mold has sufficient service life. The wear resistance of the mold depends on the chemical composition and heat treatment hardness of the steel, so increasing the hardness of the mold is beneficial to improve its wear resistance.
Machinability: Most automotive plastic parts require a certain level of cutting and fitter maintenance in addition to EMD processing. To extend the service life of cutting tools, improve cutting performance, and reduce surface roughness, the hardness of automotive plastic part steel must be appropriate.
Good polishing performance: high-quality plastic products require small surface roughness. For example, the surface roughness value of the injection mold cavity is less than Ra0.1 to 0.25, and the optical surface requires Ra<0.01nm, and the cavity must be polished to reduce the surface roughness value. The steel used for this purpose requires fewer material impurities, fine and average structure, no fiber direction, and polishing should not show pitting or orange peel defects.
Good thermal stability: The shape of injection mold parts is often more complex and difficult to process after quenching. Good thermal stability should be used as much as possible. After the mold is processed and heat-treated, the linear shrinkage coefficient is small, and the heat treatment deformation is small, due to the dimensional change rate Small, stable metallographic structure and mold size, can reduce or no longer process the temperature difference, can ensure the mold dimensional accuracy and surface roughness requirements.