The drill bits of PCB drilling have straight shank twist drills, CNC Drilling Machine fixed shank twist drills and fixed shank shovel-shaped (undercut) bits. The straight shank twist drills are mostly used for single head drilling, simple printed boards or single panels, and are now rarely seen in large-scale PCB manufacturing plants, with drilling depths up to 10 times times the drill diameter. CNC Drilling Machine In the case that the substrate stack is not high, the drill sleeve can be used to avoid drilling deviation. At present, most manufacturers use CNC drilling machine, CNC Drilling machine is the use of cemented carbide fixed shank bit, which is characterized by automatic replacement bit. High positioning accuracy, no need to use drill sleeve. The large helix angle, the chip speed is fast, is suitable for the high speed cutting. In the whole range of the chip slot, CNC Drilling Machine the bit diameter is a inverted cone, and the drilling is small with the hole wall and the drilling quality is higher. Common drill shank diameters are 3.00mm and 3.175mm.
PCB Drilling drill bits are generally used cemented carbide, because the epoxy glass cloth copper plate on the tool wear particularly fast. The so-called cemented carbide is a tungsten carbide powder as the matrix, cobalt powder as binder by pressure, sintering. Usually containing tungsten carbide 94%, containing cobalt 6%. Because of its high hardness, very wear-resistant, a certain strength, CNC Drilling Machine suitable for high-speed cutting. But the toughness is poor, very brittle, in order to improve the performance of cemented carbide, some use on the carbonized substrate chemical vapor deposition of a layer of $number micron of the Hard Titanium carbide (TIC) or titanium nitride (TIN), CNC Drilling Machine so that it has a higher hardness. Some ion implantation technology, the titanium, nitrogen, and carbon injected into the matrix of a certain depth, not only improve the hardness and strength,CNC Drilling Machine and in the bit grinding when the injected ingredients can also be inland. In addition, a layer of diamond film is generated by physical method in the head of drill, which greatly improves the hardness and wear resistance of the bit. Hardness and strength of cemented carbide are not only related to the ratio of tungsten carbide to cobalt, CNC Drilling Machine but also to powder particles. The average size of tungsten carbide phase grains is below 1 microns. This kind of drill is not only high in hardness but also in both compressive and flexural strength. In order to save costs now many drill bit using welded shank structure, the original drill bit for the whole is cemented carbide, CNC Drilling Machine now the rear part of the drill with stainless steel, the cost is greatly reduced but because of the use of different materials its dynamic concentricity less than the overall carbide bit, especially in the small diameter. CNC Drilling Machine L-carnitine which brand good external use to lose weight left-carnitine which brand good word-of-mouth repair product evaluation what children face care good best of what kind of scrub good
In the actual use process due to the problem of the bit quality is very small, such as the production of product requirements are highly recommended to use imported bit, European and American bit hardness is higher and Japan is softer, Europe and the United States bit than use is not easy to occur in the hole but the probability is higher, In Japan, the bit flexibility is more difficult to break, CNC Drilling Machine but the drilling is prone to partial porosity, especially the small bit. In the actual use of the process can be selected according to demand.