In addition to high strength and toughness, the surface performance of high-precision die accessories is very important to the working performance and service life of high-precision die accessories. It is very limited and uneconomical to rely solely on the improvement and improvement of matrix materials for the improvement of these properties. However, through surface treatment technology, we can often get twice the result with half the effort, which is the reason for the rapid development of surface treatment technology. Mold polishing technology is an important part of mold surface engineering and an important post-treatment process in mold manufacturing process. Because there are still some problems in domestic polishing technology and materials, such as injection mold for camera lens, CD, VCD discs and injection mold with high transparency requirements for tools still rely on imports.

    The mirror mold material is not only a problem of chemical composition, but also a series of advanced processes such as vacuum degassing, argon protection ingot, vertical continuous casting and rolling, flexible forging are required during smelting, so that the mirror mold steel has a series of advantages such as less internal defects, fine particle size of impurities, high dispersion, fine grain size of metal, good uniformity and so on, so as to meet the requirements of the mold steel polished to the mirror. The surface treatment technology of mold accessories is a systematic engineering that changes the shape, chemical composition, organizational structure and stress state of the surface of high-precision mold accessories through surface coating, surface modification or composite treatment technology, so as to obtain the required surface properties. Nitriding process includes gas nitriding, ion nitriding, liquid nitriding and other methods. In each nitriding method, there are several nitriding technologies, which can meet the requirements of different steel types and different workpieces. From the way of surface treatment, it can be divided into: chemical method, physical method, physical chemical method and mechanical method.

    It is worth noting that mold surface polishing is not only affected by polishing equipment and process technology, but also by the specularity of mold materials, which has not attracted enough attention, that is, polishing itself is restricted by mold materials. Although new processing technologies aimed at improving the surface properties of precision mold parts are emerging, nitriding, carburizing and hardening film deposition are mainly used in the manufacturing of high-precision mold parts. Because nitriding technology can form a surface with excellent performance, and the nitriding process is well coordinated with the quenching process of high-precision die fitting steel, at the same time, the nitriding temperature is low, there is no need for intense cooling after nitriding, and the deformation of high-precision die fittings is very small, so the surface strengthening of high-precision die fittings adopts nitriding technology earlier, and it is also the most widely used.