When the precision of precision machining is nanometer or even atomic unit (the atomic lattice distance is 0.1-0.2 nanometer), the cutting method can not adapt to it. It needs the help of special machining method, that is, the application of chemical energy, electrochemical energy, thermal energy or electric energy, to make these energies exceed the bonding energy between atoms, so as to remove the adhesion, bonding or bonding between some atoms on the workpiece surface In order to achieve the goal 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 characteristic of these methods is that the amount of material removed or added to the surface layer can be controlled very finely. However, to obtain ultra precision machining accuracy, it still depends on precision machining equipment and precise control system, and uses ultra precision mask as intermediary. For example, in VLSI plate making, electron beam is used to expose the photoresist (see lithography) on the mask to make the atoms of the photoresist polymerize (or decompose) directly under electron impact, and then the polymerized or unpolymerized parts are dissolved by the developer to make the mask. Electron beam exposure plate making requires ultra precision processing equipment with positioning accuracy of ± 0.01 micron.
What are the characteristics and functions of the system? It is an automatic machine tool controlled by program. The control system can logically process the program with control code or other symbol instructions, decode it by computer, so that the machine tool can execute the specified action, and the blank can be processed into semi-finished parts by cutting tools.
The traditional mechanical lathe processing is manual operation, ordinary machine operation, lathe processing with hand shaking mechanical tool cutting metal, rely on the eyes with calipers and other tools to measure the accuracy of the product. Modern industry has long used computer-controlled machine tools for operation, which can automatically process any product and parts according to the program compiled by technicians in advance.
The information is stored in the information carrier (such as disk, perforated tape, magnetic tape, etc.) and then read in by the CNC system on the machine tool (or directly input through the keyboard of the CNC system, or input through the communication mode). By decoding the information, the lathe can process the action and parts, and the modern CNC machine tool can be widely used It is a typical product of mechatronics and the technical foundation of new generation production technology and computer integrated manufacturing system.
The development trend of modern CNC lathe precision machining is high speed, high precision, high reliability, multi-function, compound, intelligent and open structure. The main development trend is to develop intelligent full-function universal numerical control device with open structure in both software and hardware. Numerical control technology is the basis of machining automation and the core technology of numerical control machine tools. Its level is related to the national strategic position and the level of reflecting the national comprehensive strength. It develops with the development of information technology, microelectronics technology, automation technology and detection technology. CNC machining is a kind of numerical control machine tool with tool magazine, which can automatically change the tool and process the workpiece in a certain range.
