Micro cutting tools need to be able to maintain cutting accuracy and improve wear resistance. And from the point of view of use, the range of materials to be cut is also very wide, from high hardness steel to high brittle materials such as cemented carbide and ceramics. In this case, cutting tools are increasingly using CBN (cubic boron nitride) sintered bodies and diamond sintered bodies that have better wear resistance than ordinary coated cemented carbide. However, in cutting operations with a surface roughness greater than 1μM, cemented carbide end mills are still the main tool.
Coated carbide end mills are mainly used for rough cutting of high hardness steel (partially for fine cutting). Coating technology has made continuous progress in recent years. In addition to the thinning of PVD (physical vapor deposition) coatings for micro-diameter end mills, the use of silicon-based composite coatings to improve high-temperature hardness and anti-deposition properties is also Get pushed forward. Originally, due to the effective thickness of the coating (a few microns) and adhesion strength, the minimum diameter of the commercially available coated super-hard alloy end mills was reduced to only 0.1 mm at most. However, as the coating thickness is reduced to 1μM, drills with a diameter of 10μM (Nisshin tools) have been launched, and end mills with a diameter of 10μM are also on the market.
The main technical issues of the small diameter tool itself are as follows.
①The technology of grinding the cutter head. Select diamond grinding wheel, and research and establish grinding wheel grinding technology and grinding conditions.
②In order to ensure the rigidity of the tool, design the cutting edge shape that can ensure the maximum cross-sectional area. In addition, considering the breakage resistance during cutting, the groove shape of the cutting edge is designed.
③Using ultra-ultra-fine particles with a particle size of hundreds of nanometers.
④Meet the demand for high precision. Improve cutting accuracy and extend tool life by improving cutting edge accuracy. For example, it can achieve high-precision tool grinding technology with a cutting edge diameter of within ±2μM, tool head oscillation accuracy within 2μM, and tool holder diameter accuracy of 0 to -2.5μM (JISH3 standard, roundness within 0.1μM).