In the field of machining, the machining of parts with high precision is called ultra precision machining. Ultra precision parts processing mainly includes ultra precision turning, mirror grinding and grinding equipment. In ultra precision lathe, micro turning is carried out with single crystal diamond turning tool after fine grinding. The cutting thickness is only about 1 micron. It is often used to process high precision and smooth surface parts of non-ferrous metal materials, such as spherical, aspheric and flat mirrors. For example, the aspheric mirror with a diameter of 800mm is processed for medical equipment accessories, with the highest accuracy of 0.1 μ m and surface roughness of rz0.05 μ M.
In the process of machining ultra precision parts, when the machining precision is usually nanometer or even atomic unit (atomic lattice distance is 0.1-0.2 nanometer), the machining method of ultra precision parts can not adapt to it. It is necessary to use the machining method of special precision parts, that is, chemical energy, electrochemical energy, thermal energy or electric energy, to make these energies exceed the binding energy between atoms, So as to remove the attachment, bonding or lattice deformation of some atoms on the surface of the workpiece, so as to achieve the purpose of ultra precision machining. This kind of processing includes mechanical chemical polishing, ion sputtering and ion implantation, electron beam exposure, laser beam processing, metal evaporation and molecular beam epitaxy.
The main feature of ultra precision parts machining is that the amount of material removed or added to the surface layer can be controlled very finely. However, to obtain the machining accuracy of ultra precision parts, it still depends on precision machining equipment and precise control system, and uses ultra precision mask as intermediary. For example, the plate making of integrated circuits in the electronic industry is to use the electron beam to expose the photoresist (see lithography) on the mask to make the atoms of the photoresist polymerize (or decompose) directly under the electron impact, and then use the developer to dissolve the polymerized or unpolymerized part to make the mask. Electron beam exposure plate making requires the positioning accuracy of worktable up to 100% ± 0.01 micron ultra precision machining equipment.
The so-called high quality comes from exquisite technology. High quality is inseparable from high quality technology, precision processing equipment and reasonable processing technology.
ken. tang@chengcg.com
