In addition to strong enough strength and toughness, surface properties are essential for the performance and service life of high-precision mold parts. These performance improvements, which rely solely on the improvement of the matrix material itself, are very limited and uneconomical, but surface treatment techniques can often achieve twice the result with half the effort, which is why surface treatment technology has developed rapidly. Mold polishing technology is an important part of mold surface engineering and an important process for post-processing in mold manufacturing. Due to certain problems in domestic polishing technology and materials, injection molds such as point-and-shoot lenses, CDs, VCDs, and tools with high transparency requirements still depend heavily on imports.

Mirror finish mold material is not only a chemical component problem, but also requires a series of advanced processes such as vacuum degassing, argon gas protection ingot casting, vertical continuous casting and rolling, and soft forging during smelting, so that the mirror finish mold steel has fewer internal defects. A series of advantages such as fine particle size, high degree of dispersion, fine metal grain size and good uniformity, in order to achieve the requirements of polishing to mirror finish mold steel. The surface treatment technology of mold parts is the systematic engineering of changing the surface morphology, chemical composition, microstructure and stress state of high-precision mold parts by surface coating, surface modification or composite processing technology to obtain the desired surface properties. The nitriding process has the methods of gas nitriding, ion nitriding, liquid nitriding, etc. In each nitriding mode, there are several kinds of nitriding techniques, which can adapt to the requirements of different workpieces of different steel types. From the way of surface treatment, it can be divided into: chemical methods, physical methods, physical and chemical methods, and mechanical methods.

We should pay attention that the surface polishing of the mold is not only affected by the polishing equipment and process technology, but also affected by the mirror finish grade of the mold material. This has not caused enough attention, that is, the polishing itself is restricted by the mold material. Although new treatment technologies aimed at improving the surface properties of precision mold parts continue to emerge, the main applications in the manufacture of high-precision mold parts are nitriding, carburizing and hardening film deposition. Because nitriding technology can form a surface with excellent performance, and the nitriding process has good coordination with the quenching process of high-precision mold parts steel, and the nitriding temperature is low, there is no need for intense cooling after nitriding, and the deformation of high-precision mold parts Very small, so the surface strengthening of high-precision mold parts is the earliest and most widely used nitriding technology.