Ultra-hard tools play an important role in automobile, aerospace, energy, military and mechanical fields. Ultra-hard cutters refer to tools made of diamond, cubic boron nitride (CBN) and other superhard materials and composite materials. At present, PCD (Polycrystalline Diamond) and PCBN (Polycrystalline Cubic Boron Nitride) cutters are the main tools.
As a superhard tool material, diamond has been used in processing for hundreds of years. In the process of tool development, tool materials for knives are constantly reformed, upgraded and innovated. With the successful birth of polycrystalline diamond prepared by high-pressure synthesis technology, synthetic polycrystalline diamond has become an effective substitute for natural diamond. The material problem of diamond tools has been effectively solved, making the use of diamond tools expand from diamond materials, electronics and automobiles to aerospace fields.
Diamond tools have the advantages of high hardness, high compressive strength, good thermal conductivity and good wear resistance. The surface Vickers hardness of polycrystalline diamond is high, and the surface Vickers hardness of cemented carbide is much lower than that of polycrystalline diamond. Polycrystalline diamond cutters do not suffer from the problems of heat collection and workpiece burns due to slow heat export during production, because their thermal conductivity is higher than that of copper. Cutting force of the polycrystalline diamond cutter can be significantly reduced because the friction coefficient of polycrystalline diamond cutter is generally only 0.1 to 0.3, which is only about one third of the friction coefficient of cemented carbide, and the thermal expansion coefficient of polycrystalline diamond is about one fifth of that of cemented carbide. In addition, polycrystalline diamond cutters are not easy to produce stickers in the process of production and use, and the chip is not easy to bond to the tip to form chips, because the affinity between polycrystalline diamond and non-metallic and non-ferrous metal materials is very low.
Polycrystalline diamond cutters are mainly used in the following two aspects: (1) nonferrous metal materials processing, nonferrous metal processing. If the common tools are used, it is easy to produce tool wear, low processing efficiency and other defects. Polycrystalline diamond cutters show excellent processing performance. (2) For the processing of non-metallic materials, polycrystalline diamond cutters are suitable for processing non-metallic materials which are difficult to process.