It has the characteristics of high hardness, high compressive strength, good thermal conductivity and wear resistance, and can achieve high machining accuracy and efficiency in high-speed cutting. The above characteristics of diamond cutting tools are determined by the state of diamond crystals. In diamond crystals, the four valence electrons of carbon atoms form tetrahedral bonds, and each carbon atom forms covalent bonds with four adjacent atoms to form a diamond structure. This structure has strong binding force and directionality, making diamond extremely hard. Due to the fact that the structure of polycrystalline diamond (PCD) is a sintered body of fine grain diamond with different orientations, even with the addition of binders, its hardness and wear resistance are still lower than those of single crystal diamond. However, due to the isotropic nature of PCD sintered bodies, they are not easily cracked along a single cleavage plane.