Diamond cutting tool (PCB) materials have the highest hardness among known cutting tool materials, as well as high thermal conductivity and elastic modulus, low coefficient of expansion and friction. Due to the easy reaction between carbon and iron, diamond cutting tools cannot process iron and its alloy materials, but they have good cutting performance on aluminum alloy materials, with cutting speeds of up to 2500-5000 m/min. Cubic boron nitride (CBN) cutting tools emerged in the 1950s, with slightly lower hardness than diamond cutting tools. Cubic boron nitride cutting tools have high red hardness, thermal conductivity, and stable chemical properties, and their cutting performance is significantly better than traditional hard alloy materials. They are suitable for precision small batch difficult to machine materials. However, cubic boron nitride cutting tools are expensive and not suitable for large-scale processing.