Electric hammer drill material which has several?
The drill bits used in printed circuit boards are generally made of cemented carbide, because the epoxy glass cloth and copper clad plate are very fast to wear the cutters. The so-called carbide is based on tungsten carbide powder as a matrix, cobalt powder as binder, by compression and sintering. Usually containing tungsten carbide 94%, cobalt containing 6%.
Because of its high hardness, very wear-resistant, has a certain strength, suitable for high-speed cutting. But the poor toughness, very brittle, in order to improve the performance of the hard alloy, with some hard carbide titanium carbide substrate in chemical vapor deposition of a layer of 5 to 7 microns (TIC) or titanium nitride (TIN), which has higher hardness. Some use ion implantation technology to inject titanium, nitrogen and carbon into the substrate at a certain depth, which not only improves the hardness and strength, but also makes them move when the drill is regrinding.
Also, a diamond film is formed at the top of the drill bit by physical means, which greatly improves the hardness and wear resistance of the drill bit. The hardness and strength of cemented carbide are not only related to the ratio of tungsten carbide to cobalt, but also to the particle of powder. A cemented carbide drill bit with an average size of 1 microns. This kind of drill not only has high hardness, but also improves the compressive and bending strength. In order to save the cost of many bits by welding handle structure, the original bit for the whole hard alloy drill, the back part of the handle adopts stainless steel, but the cost is greatly reduced due to the use of different materials and its dynamic concentricity is inferior to the whole hard alloy bit, especially in the aspect of small diameter.
