Application of coating technology
In the case of constant cutting parameters, in order to improve production efficiency and reduce production costs, it has become a trend to use coating technology to reduce tool wear and improve tool durability.
Tool coating refers to coating a thin layer of refractory metal or nonmetal compound with good wear resistance on the surface of hard alloy or high speed steel (HSS) substrate with good strength and toughness by means of vapor deposition. The coating acts as a chemical and thermal barrier, reducing the diffusion and chemical reaction between the tool and the workpiece, thereby reducing tool wear. Coated cutting tools are characterized by high surface hardness, good wear resistance, stable chemical properties, heat resistance and oxidation resistance, small friction coefficient and low thermal conductivity.
After the coating, the number of bit processing has been significantly increased, and the cost per piece has been greatly reduced.
The hardness and strength of cemented carbide are not only related to the ratio of tungsten carbide and cobalt, but also related to the particle size of the powder. The average grain size of tungsten carbide phase of ultra-fine cemented carbide bit is less than 1 micron. This kind of bit not only has higher hardness but also has improved compressive and bending strength. In order to save costs, many drill bits now use welded shank construction. The original drill bit was made of solid carbide, but now the rear shank is made of stainless steel. The cost is greatly reduced, but because of the different materials, the dynamic concentricity is not as good as that of solid carbide bits, especially in the small diameter area.