Tool coating technology plays an important role in modern cutting and tool development. It has developed very rapidly since its inception, especially in recent years. Chemical coating (CVD) is still the main coating for indexable inserts. The layer process has successively developed new processes such as medium temperature CVD, thick film aluminum oxide, and transition layer. On the basis of the improvement of the base material, the wear resistance and toughness of the CVD coating are improved; and the physical coating ( PVD) technology has also made major breakthroughs, and has made significant progress in the structure, process, and automatic control of coating equipment, and developed a heat-resistant coating suitable for high-speed cutting, dry cutting, and hard cutting. Through the innovation of the coating structure, a large number of new coatings such as nano- and multi-layer structures have been developed, which greatly improves the precision mold manufacturing hardness and toughness of the coating. Superhard materials refer to diamond and cubic boron nitride (CBN), which are several times harder than other tool materials. Diamond is the hardest substance in nature, and CBN is second only to diamond.
In recent years, superhard tool materials have developed rapidly. Diamond tool materials are divided into five categories: natural diamond (ND), synthetic polycrystalline diamond compact (PCD/CC), diamond film coated tool (CD), diamond thick film tool (FCD) and synthetic polycrystalline diamond (PCD). . The crystal anisotropy of ND must be selected in the appropriate direction when using the knife grinding; the synthetic diamond is isotropic, its hardness is lower than ND, but the strength and toughness are better than ND. Diamond tools can efficiently process non-ferrous and non-metallic materials. Such as copper, tungsten and other non-ferrous metals and their alloys, ceramics, hard alloys, various fiber and particle reinforced composite materials, plastics, rubber, graphite, glass and wood, but diamonds do not cut steel and other iron elements. Cubic boron nitride (CBN) tool material is extremely hard and hard, and is an ideal tool material for high-speed finishing or semi-finishing hardened steel, chilled cast iron, superalloy, which can be obtained when CBN tools are used to process high hardness parts. Good surface roughness, so cutting with hardened steel with CBN tools can achieve “cutting and grinding”.
In the future development of tool materials, the development of high-speed steel materials is still mentioned. Although the sales of high-speed steel materials are decreasing year by year, the use of high-performance cobalt high-speed steel and powder metallurgy high-speed steel is still increasing. Two high-performance high-speed steels have better wear resistance, red hardness and reliability than ordinary high-speed steel. These high-performance high-speed steel tools have been widely adopted in the aviation field as people pursue improvements in cutting efficiency and change in concept. Such as aviation difficult-to-machine materials, drilling, expanding, reaming, and boring integrated high-precision composite tools used in automatic drilling and riveting machines, as well as various composite tools for machining complex profiles of aircraft parts.
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