In ultra-precision machining,the main factors to ensure the quality of the machined surface are high-quality tools,in addition to high-precision machine tools and ultra-stable machining environments.Single crystal diamond has high hardness,good wear resistance,high strength,good thermal conductivity,low friction coefficient with non-ferrous metals,good anti-adhesiveness,excellent corrosion resistance and chemical stability, and can sharpen extremely sharp edges.It is considered to be the most ideal tool material for ultra-precision cutting, and has an important position in the field of machining,especially in the field of ultra-precision machining.
In the late 1970s,in the research of laser nuclear fusion technology,it was necessary to process a large number of high-precision soft metal mirrors,which required the surface roughness and shape accuracy of soft metals to reach ultra-precision levels. If the traditional grinding and polishing methods are used,not only the processing time is long,the cost is high, the operation is difficult,and the required precision is not easily achieved.Therefore,there is an urgent need to develop new processing methods. Driven by real-world demand, single-crystal diamond ultra-precision cutting technology has been rapidly developed.Due to the physical properties of single crystal diamond,it is not easy to stick to the knife and produce built-up edge when cutting. The surface quality is good. When processing non-ferrous metals, the surface roughness can reach Rz0.1~0.05μm.Single crystal diamond tools can also effectively process non-ferrous metal materials and optical materials, such as gold, silver, copper, aluminum and other non-ferrous metals and sapphire,zinc selenide,zinc sulfide,silicon,Ge,calcium fluoride,barium fluoride,Optical materials such as optical glass and ceramic crystals.
In ultra-precision machining,the two basic accuracies of a single crystal diamond tool are the accuracy of the blade profile and the blunt radius of the cutting edge.It is required that the roundness of the arc cutting edge for machining an aspherical lens is 0.05 μm or less,and the straightness of the cutting edge for machining a polyhedral mirror is 0.02 & mu; m; the blunt radius of the cutting edge of the tool (ρ value) is expressed The sharpness of the cutting edge of the tool,in order to adapt to various processing requirements,the blade edge radius ranges from 20nm to 1μm.