At present, the grinding of single crystal diamond tools can be divided into mechanical grinding and non-pure mechanical grinding two methods, in addition to the original mechanical grinding based on aerostatic bearing high-precision grinding disc, domestic and foreign scholars have developed a variety of new grinding methods in recent years.
(1) Ion beam spatter etching method
Ion beam spatter etching method is to use high-energy ion bombardment to directly physical spatter etching on the cutting edge of the processed diamond tool, in order to achieve atomic micro machining. The machining efficiency and edge quality are related to ion beam energy, current density and Angle between ion beam and tool surface. Ion beam spillage is most suitable for machining tiny diamond tools with size less than 1μm and can achieve high shape accuracy.
(2) Vacuum plasma chemical polishing method
The rotating grinder is divided into left and right parts by the high vacuum in the middle. On the left is the deposition area, the surface of the grinding disc is coated with a layer of fine grain silicon oxide. On the right is the grinding zone, the activated carbon atoms on the diamond surface react with the silicon oxide on the grinding disc at molecular level and play the role of the cutting edge of the grinding tool. The carbon monoxide or carbon dioxide gas produced by the reaction is extracted by a vacuum pump. The grinding speed of this method is 1 ~ 3000μm3/s, about 0.25 ~ 750 atomic layers per second, which can grind very high edge quality. This method was first used to grind ultra-precision diamond mirror cutting tools by Edge Technologies, inc., and is widely used for machining ultra-fine surfaces with various nanoscale precision.
(3) No damage mechanochemical polishing method
This method is to join the right amount of diamond powder in aqueous solution and a more subtle level (Dana meters) silicon powder, fine silicon powder with strong negative electrostatic adsorption in much bigger granularity of single diamond particles with silica adsorption layer is formed on the diamond abrasive, and then the coating on porous iron mill for grinding processed diamond. The grinding efficiency of this method is very low, only one atomic layer per minute, but the cutting edge quality is very good.
(4) thermochemical polishing method
When the temperature is 800℃, if the diamond surface contacts with iron, the carbon atoms in diamond crystal can get rid of the constraints of their own lattice and diffuse into the lattice of iron crystal. The thermochemical polishing method uses this mechanism to grind diamond surface. The grinding efficiency of this method is 40 ~ 2000 atomic layers per second.
The surface roughness of diamond is up to 1nm, the edge is very sharp (ρ≤0.1μm) and the metamorphic layer of diamond tool is shallow. The disadvantage is that the grinding efficiency is low, and it is suitable for super finishing grinding after finishing.
--- EDITOR：Yvonne Feng
--- POST：Yvonne Feng