The surface treatment technology of mould is a system engineering that changes the surface morphology, chemical composition, microstructure and stress state of mould through surface coating, surface modification or composite treatment technology to obtain the required surface properties. From the way of surface treatment, it can be divided into chemical method, physical method, physical chemical method and mechanical method. Although new treatment technologies are emerging to improve the surface properties of moulds, nitriding, carburizing and hardening film deposition are widely used in the production of plastic moulds.
Nitriding process includes gas nitriding, ion nitriding and liquid nitriding. In each nitriding method, there are several nitriding technologies, which can meet the requirements of different steel grades and different workpieces. Because nitriding technology can form excellent performance surface, and nitriding process and die steel quenching process have good coordination, at the same time, nitriding temperature is low, after nitriding does not need intense cooling, die deformation is very small, therefore, nitriding technology is used earlier, and it is also widely used.
The purpose of mold carburizing is to improve the overall strength and toughness of the mold, that is, the working surface of the mold has high strength and wear resistance. The technical idea is to use lower grade materials, that is, to replace higher grade materials by carburizing and quenching, so as to reduce the manufacturing cost.
3. Hardening film deposition
At present, CVD and PVD are the mature deposition technologies of hardened film. In order to increase the bonding strength between the film and the workpiece surface, a variety of enhanced CVD and PVD technologies have been developed.
Hardening film deposition technology has been used in tools (cutting tools, cutting tools, measuring tools, etc.) for a long time, and the effect is good.
Through the surface treatment technology, the wear resistance, corrosion resistance, friction coefficient and fatigue performance of the die have been greatly improved, which also improves the life of the die. So as to achieve the purpose of cost saving for manufacturers.