The development of ultra-precision machining has gone through the following three stages.
(1) the 1950s to the 1980s for the technology pioneering period. the late 1950s, out of aerospace, national defense and other cutting-edge technology development needs, the United States took the lead in the development of ultra-precision machining technology, the development of ultra-precision cutting diamond tools - single point diamond cutting (Single point diamond tuming) technology, also known as "micro-inch technology", also known as "micro-inch technology", the development of ultra-precision machining. Single point diamond cutting (Single point diamond tuming, SPDT) technology, also known as "micro-inch technology", for processing laser fusion mirrors, tactical missiles and manned spacecraft with spherical, aspheric large parts. Since 1966, the United States unionCarbide Company, the Netherlands Philips Company and the United States LawrenceLivemoreLaboratories have launched their own ultra-precision diamond lathe, but its application is limited to a small number of large companies and research units of the experimental research, and to the national defense purposes or scientific research purposes of the product processing is given priority to. During this period, the diamond lathe was mainly used for the processing of copper, aluminum and other soft metals, and it could also process workpieces with more complicated shapes, but it was limited to workpieces with axisymmetric shapes such as aspherical mirrors. (2) The 1980s to 1990s for the early stage of private industry applications. In the 1980s, the U.S. government to promote a number of private companies Moore Special Tool and Pneumo Precision Company began the commercialization of ultra-precision machining equipment, and a number of companies in Japan, such as Toshiba and Hitachi and Europe's Cmfield University, etc. have also launched products, these devices began to face the general private industry Manufacturing of optical components. However, at this time, ultra-precision machining equipment was still expensive and rare, and was mainly customized in the form of special machines. During this period, in addition to diamond lathes for processing soft metals, ultra-precision diamond grinding was developed for processing hard metals and hard brittle materials. This technology is characterized by the use of a highly rigid mechanism for ductile grinding of brittle materials with a very small depth of cut, which allows hard metals and brittle materials to obtain nanometer-scale surface roughness. Of course, its processing efficiency and the complexity of the mechanism can not be compared with the diamond lathe. the late 1980s, the United States through the Department of Energy "laser fusion project" and the Army, Navy and Air Force "Advanced Manufacturing Technology Development Program" on the development and research of ultra-precision diamond cutting machine tools, invested heavily in the development and research of ultra-precision diamond cutting machine tools. Machine tool development and research, invested huge sums of money and a lot of manpower to achieve the micro-inch ultra-precision machining of large parts. The United States LLNL National Laboratory developed a large optics diamond turning machine (Large optics diamond turning machine, LODTM) has become a classic in the history of ultra-precision machining. This is a maximum processing diameter of 1.625m vertical lathe, positioning accuracy of up to 28nm, with the help of online error compensation capabilities, can realize the length of more than 1m, and straightness error only Shi 25nm processing. (3) the 1990s to the present for the maturity of private industrial applications. From 1990 onwards, due to the booming development of the automotive, energy, medical devices, information, optoelectronics and communications industries, the demand for ultra-precision machining machines has increased dramatically, in the industrial sector, including aspheric optics, Fresnel lenses, ultra-precision molds, disk drive heads, disk substrate processing, semiconductor wafer dicing and so on. During this period, the technology related to ultra-precision machining equipment, such as controllers, laser interferometers, air bearing precision spindles, air bearing guides, hydraulic bearing guides, friction-driven feed axes are also maturing, and ultra-precision machining equipment is becoming a common production machine and equipment in the industrial world, with many companies, even small ones, launching mass-produced equipment. In addition, the precision of the equipment is also gradually approaching the nanometer level, the processing stroke becomes larger, the processing application is also gradually widening, in addition to diamond lathe and ultra-precision grinding, ultra-precision five-axis milling and fly-cutting technology has also been developed, and can be processed non-axisymmetric aspheric optical lenses. The world's strongest countries in ultra-precision machining are Europe, the United States and Japan, but their research priorities are not the same. Europe and the United States out of the importance of energy or space development, especially the United States, over the past few decades, continue to invest huge sums of money, large ultraviolet, x-ray detection telescopes, large aperture mirrors for processing research. Such as the U.S. Space Agency (NASA) to promote the space development program to produce more than 1m mirror as the goal, the purpose is to detect x-rays and other short-wave (O.1 ~ 30nm). Because of the high energy density of X-rays, it is necessary to improve the reflectivity by making the surface roughness of the mirror reach the angstrom level. The material for these mirrors is silicon carbide, which is lightweight and has good thermal conductivity, but silicon carbide is very hard and requires ultra-precision grinding and processing. Japan's research on ultra-precision machining technology relative to the United States and the United Kingdom started late, but today the world's ultra-precision machining technology is the fastest growing country. Japan's ultra-precision machining applications are mostly civilian products, including office automation equipment, video equipment, precision measuring instruments, medical equipment and artificial organs. Japan in sound, light, image, office equipment in small, ultra-small electronic and optical parts of the ultra-precision machining technology, has the advantage, and even exceeded the United States. Japan's ultra-precision machining initially started with diamond cutting of aluminum and copper wheels, and then concentrated on the mass production of magnetic disks for computer hard disks, followed by fast diamond cutting of multifaceted mirrors for laser printers and other equipment, and then ultra-precision machining of optical components such as aspherical lenses. l982 EastnlanKodak digital camera, which came on the market in 1982, used an aspherical lens that attracted a lot of attention from the Japanese Industry is widely concerned, because an aspherical lens can replace at least three spherical lenses, optical imaging system is thus miniaturized, lightweight, and can be widely used in cameras, VCRs, industrial TVs, robot vision, CDs, VCDs, DvDs, projectors and other optoelectronic products. As a result, precision molding of aspherical lenses has become a hot research topic in the Japanese optical industry. Although ultra-precision machining technology is constantly being updated and machining accuracy is constantly being improved as times change, and the focus of research differs between countries, the factors that promote the development of ultra-precision machining are essentially the same. These factors can be summarized as follows. (1) The pursuit of high product quality. In order to make the magnetic disk storage density is higher or the optical performance of the lens is better, it is necessary to obtain a lower roughness of the surface. In order to make electronic components function properly, it is required that the surface after processing can not be left after processing deterioration layer. According to the American Microelectronics Technology Association (SIA) put forward the technical requirements, the next generation of computer hard disk heads require surface roughness Ra ≤ 0.2nm, disk requirements surface scratch depth h ≤ lnm, surface roughness Ra ≤ 0.1nmp. 1983 TANIGUCHI on the machining accuracy of the various periods of time to summarize and its development trend prediction, based on this. BYRNE depicts the development of machining accuracy after the 1940s.
(2) The pursuit of product miniaturization. Accompanying the increase in machining accuracy has been a reduction in the size of engineering components. From 1989 to 2001, it was reduced from 6.2kg to 1.8kg. The high integration of electronic circuits requires a reduction in the surface roughness of silicon wafers, an increase in the precision of lenses used for circuit exposure, and the precision of movement of semiconductor manufacturing equipment. The miniaturization of components means that the ratio of surface area to volume is increasing, and the surface quality of the workpiece and its integrity is becoming increasingly important.
(3) The pursuit of high product reliability. For bearings and other parts that are subjected to relative motion while bearing loads, reducing surface roughness improves the wear resistance of the parts, improves their work stability, and extends their service life. The surface roughness of Si3N4 ceramic balls used in high-speed, high-precision bearings is required to reach several nanometers. Processing of the chemical nature of the metamorphic layer is active and susceptible to corrosion, so from the point of view of improving the corrosion resistance of the parts, the requirements of the processing of the resulting metamorphic layer as small as possible. (4) The pursuit of high product performance. Improvement in the precision of institutional movement is conducive to slowing down the fluctuation of mechanical properties, reduce vibration and noise. For internal combustion engines and other machinery requiring high sealing, good surface roughness can reduce leakage and reduce losses. After World War II, the aerospace industry requires some parts to work in high temperature environments, and thus the use of titanium alloys, ceramics and other difficult-to-machine materials for the ultra-precision machining of a new subject.