Generally, cemented carbide is used as the drill bit for PCB drilling, because the epoxy glass cloth copper clad plate wears the tool very quickly. The so-called cemented carbide is made by pressing and sintering tungsten carbide powder as matrix and cobalt powder as binder. Usually it contains 94% tungsten carbide and 6% cobalt. Because of its high hardness, wear resistance and certain strength, it is suitable for high-speed cutting. However, its toughness is very poor and it is very brittle. In order to improve the properties of cemented carbide, a layer of superhard titanium carbide (TIC) or titanium nitride (TIN) with a diameter of 5 ~ 7 microns was deposited on the carbonized matrix by chemical vapor deposition, which made it have higher hardness. Some use ion implantation technology to implant titanium, nitrogen and carbon into their matrix to a certain depth, which not only improves the hardness and strength, but also allows these injected components to move inward when the drill bit is reground. Others use physical methods to form a diamond film on the top of the drill, which greatly improves the hardness and wear resistance of the drill. The hardness and strength of cemented carbide are not only related to the proportion of tungsten carbide and cobalt, but also related to the particles of powder. The average grain size of tungsten carbide phase of ultrafine cemented carbide drill bit is below 65438 0 micron. This kind of drill bit not only has high hardness, but also has improved compressive and bending strength. In order to save cost, many drill bits adopt the structure of welding handle. The original drill bit adopts cemented carbide as a whole, and the drill handle behind it adopts stainless steel, which greatly reduces the cost. However, due to the different materials used, its dynamic concentricity is not as good as that of the whole cemented carbide bit, especially when the diameter is small.