Introduction to machining and special machining of ultra-precision parts

Ultra-precision parts machining mainly includes ultra-precision turning, mirror grinding and grinding. It is micro-turned on a super-precision lathe with a finely ground single crystal diamond turning tool. The cutting thickness is only about 1 micron. It is often used for the processing of spherical, aspherical and planar mirrors of non-ferrous materials with high precision and high surface height. Components. For example, an aspherical mirror with a diameter of 800 mm for processing a nuclear fusion device has a maximum precision of 0.1 μm and a surface roughness of Rz 0.05 μm.

Ultra-precision parts special processing

Ultra-precision parts processing accuracy is nanometer, and even when the atomic unit (atomic lattice distance is 0.1-0.2 nm) is targeted, the ultra-precision part cutting method can not be adapted, and it is necessary to use the special precision part processing method, namely, applied chemistry. Energy, electrochemical energy, thermal energy or electrical energy, such that the energy exceeds the bonding energy between the atoms, thereby removing the adhesion, bonding or lattice deformation between some of the atoms on the surface of the workpiece to achieve ultra-precision processing. Among these processes are mechanochemical polishing, ion sputtering and ion implantation, electron beam exposure, laser beam processing, metal evaporation, and molecular beam epitaxy.

These ultra-precision part processing methods are characterized by extremely fine control of the amount of surface layer material removed or added. However, in order to obtain the precision of ultra-precision parts processing, it still relies on precise processing equipment and precise control system, and uses ultra-precision mask as an intermediary. For example, the plate making of a very large scale integrated circuit uses an electron beam to expose a photoresist (see photolithography) on the mask, so that the atoms of the photoresist are directly polymerized (or decomposed) under electron impact, and then The polymerized or unpolymerized portion is dissolved with a developer to form a mask. Electron beam exposure plate making requires ultra-precision processing equipment with a table positioning accuracy of ±0.01 μm.