The Function Of Carbide Drill Bit

The grinding crack on the surface of the whole cemented carbide tool is mainly caused by the high local instantaneous temperature of the grinding contact zone in the grinding process, the compressive stress distribution and the higher tensile stress value of the near surface layer than the broken strength of the material. Therefore, in the grinding process should be minimized and avoid the emergence of instantaneous high temperature, It also reduces and avoids the generation of residual tensile stress.Carbide Drill Bit

The instantaneous high temperature in the grinding process often causes the change of the mechanical properties of the grinding surface layer, which can reach more than 1000 ℃, and cause grinding burn on the surface layer of the tool. Grinding burns can destroy the surface layer of the tool, make the quality of the workpiece deteriorate, seriously affect the strength, wear resistance and service life of the tool, and crack will also occur when serious. Therefore, not only to prevent the production of grinding cracks, but also to avoid grinding burns. In diamond processing, the local instantaneous temperature of the tool surface will depend on the processing method, the diamond tool characteristic and the grinding system.Carbide Drill Bit

The higher the line velocity and radial feed rate of diamond grinding wheel, the more hardness of the grinding wheel, the finer granularity of the grinding wheel, the lower the thermal conductivity of the tool material and the more severe the grinding wheel wear, the more severe the grinding temperature is, the more easily the grinding crack and the grinding burn. To control and avoid grinding cracks and grinding burns, two measures must be taken: one is to reduce the production of grinding heat, and the second is to accelerate the heat of grinding. The method of reducing the grinding heat is: to reduce the line speed of diamond grinding wheel properly, to reduce the diameter to feed (coarse grinding-grinding-polishing process), select softer diamond grinding wheel, decrease the contact area of workpiece and grinding wheel, and choose the granularity of grinding wheel according to the grinding requirement. The grinding wheel is often kept under sharp conditions and the suitable grinding coolant is selected to reduce friction between the abrasive grains and the workpiece.Carbide Drill Bit

The measures of accelerating the heat transmission of the grinding are the effective cooling methods except the proper progress of the workpiece speed and axial feed, and the cooling oil with spray cooling, high pressure cooling, inner cooling and low motion viscosity can be used in order to improve the cooling effect. In addition, the reduction of feed and proper light grinding can effectively reduce the residual stress in the surface.Carbide Drill Bit