With high hardness, high compressive strength, high compressive strength, good thermal conductivity and wear resistance, diamond cutter possesses high machining accuracy and efficiency in high-speed cutting. Those characteristics of diamond cutter are determined by the state of diamond crystal. In diamond crystals, four valence electrons of carbon atoms are bonded with tetrahedral structure, and each carbon atom forms covalent bond with four adjacent atoms, thus forming diamond structure. This structure enjoys strong binding force and directionality, which makes diamond has extremely high hardness. Though the binder is added into polycrystalline diamond (PCD blanks), its hardness and wear resistance are still lower than that of monocrystalline diamond. However, PCD sinter is isotropic, so it is not easy to crack along a single cleavage plane.
The research of PCD cutter in industrially advanced country has been carried out earlier, and its application has been relatively mature. Since the first synthesis of synthetic diamond in Sweden in 1953, a large number of achievements have been made in the research of cutting performance of PCD cutter. The application scope and amount of PCD cutter have been rapidly expanded. The application range of PCD cutter has been extended from initial turning to drilling and milling. A survey of super-hard cutting tools conducted by a Japanese organization shows that the main factors that people choose PCD cutting tools are based on the advantages of surface accuracy, dimension accuracy and tool life after PCD cutting tools are processed. The synthetic technology of diamond composite sheet has also been greatly developed.