company news about Development Status of Ultra-Precision Machining Technology

^{Since China listed "equipment manufacturing" as its national development strategy, China's equipment manufacturing industry has achieved rapid development. The manufacturing capacity of many large-scale equipment has leaped to the world's advanced level, and has even become the world's top level. The overall industry is still backward, and its backwardness lies in the backwardness of precision manufacturing.}

^{Ultra-precision machining technology is an important supporting technology for modern high-tech warfare, the basis for the development of modern high-tech industries and science and technology, and the development direction of modern manufacturing science.}

^{The development of modern science and technology is based on experiments, and almost all of the required experimental instruments and equipment do not require the support of ultra-precision machining technology. From macro-manufacturing to micro-manufacturing, one of the future development trends of the manufacturing industry, the current ultra-precision machining has entered the nano-scale, and nano-manufacturing is a topic at the forefront of ultra-precision machining. Developed countries all over the world attach great importance to it.}

^{The development stage of ultra-precision machining}

^{The current ultra-precision machining is based on the premise of not changing the physical properties of the workpiece material to obtain the ultimate shape accuracy, dimensional accuracy, surface roughness, surface integrity (no or very little surface damage, including microcracks and other defects, residual stress , organizational change) as the goal.}

^{The research content of ultra-precision machining, that is, various factors that affect the accuracy of ultra-precision machining include: ultra-precision machining mechanism, processed materials, ultra-precision machining equipment, ultra-precision machining tools, ultra-precision machining fixtures, ultra-precision machining detection and errors compensation, ultra-precision machining environment (including constant temperature, vibration isolation, clean control, etc.) and ultra-precision machining technology. For a long time, scholars at home and abroad have carried out systematic research on these contents. The development of ultra-precision machining has gone through the following three stages.}

^{1) From the 1950s to the 1980s, the United States took the lead in developing ultra-precision machining technology represented by single-point diamond cutting, which was used for the processing of large-scale laser fusion mirrors, spherical and aspherical parts in aerospace, national defense, astronomy and other fields. .}

^{2) From the 1980s to the 1990s, it entered the initial stage of application in the private industry. Moore, Pretek in the United States, Toshiba and Hitachi in Japan, and Cranfield in Europe, with the support of the government, commercialized ultra-precision machining equipment and began to use it in the manufacture of civilian precision optical lenses. Single ultra-precision machining equipment is still scarce and expensive, and it is mainly customized in the form of special machines. During this period, ultra-precision diamond grinding technology and grinding machines that can process hard metals and hard and brittle materials also appeared, but their processing efficiency could not be compared with diamond lathes.}

^{3) After the 1990s, the civilian ultra-precision machining technology gradually matured. Driven by industries such as automobiles, energy, medical equipment, information, optoelectronics and communications, ultra-precision machining technology is widely used in the processing of aspherical optical lenses, ultra-precision molds, disk drive heads, disk substrates, semiconductor substrates and other parts. As the related technologies of ultra-precision machining equipment, such as precision spindle components, rolling guides, static pressure guides, micro-feed drives, precision numerical control systems, and laser precision inspection systems, gradually mature, ultra-precision machining equipment has become a common production in the industry. equipment. In addition, the precision of the equipment is gradually approaching the nanometer level, the size range of the workpieces that can be processed has become larger, and the application is more and more extensive. With the development of numerical control technology, ultra-precision five-axis milling and flying cutting technology have also appeared. Complex parts such as non-axisymmetric aspheric surfaces can already be processed.}

^{The development of foreign ultra-precision machining}

^{The United States, the United Kingdom and Japan are internationally leading countries in ultra-precision machining technology. The ultra-precision machining technology in these countries not only has a high overall level of complete sets, but also has a very high degree of commercialization.}

^{The United States did not develop the ultra-precision cutting technology of diamond tools in the 1950s, called "SPDT technology" (Single Point Dia-mond Turning) or "micro-inch technology" (1 micro-inch = 0.025 μm), and developed the corresponding air bearing The ultra-precision machine tool of the main shaft is used to process large spherical and aspherical parts for laser fusion mirrors, tactical missiles and manned spacecraft.}

^{In terms of large-scale ultra-precision machine tools, the LLL National Laboratory in the United States successfully developed two large-scale ultra-precision diamond lathes in 1986: one is a horizontal DTM-3 diamond lathe with a machining diameter of 2.1m, and the other is a machining diameter of 1.65m. The LODTM Vertical Large Optical Diamond Lathe. Among them, LODTM vertical large optical diamond lathe is recognized as the ultra-precision machine tool with the highest precision in the world. The United States later developed a large-scale 6-axis CNC precision grinding machine for precision grinding of large optical mirrors.}

^{The Cranfield Institute of Precision Engineering (CUPE), which belongs to the Cranfield Institute of Technology in the United Kingdom, is a unique representative of the British ultra-precision machining technology level. For example, the Nanocentre (Nano Machining Center) produced by CUPE can perform ultra-precision turning, with a grinding head, and ultra-precision grinding. The shape accuracy of the processed workpiece can reach 0.1 μm, and the surface roughness Ra<10 nm.}

^{Cranfield Precision Machining Center successfully developed OAGM-2500 multi-function three-coordinate CNC grinding machine in 1991 (table area 2500mm×2500mm), which can process (grinding, turning) and measure precision free-form surfaces. The machine tool adopts the method of splicing workpieces, and can also process large mirrors with a diameter of 7.5m in astronomical telescopes.}

^{Compared with the United States and the United Kingdom, Japan's research on ultra-precision machining technology started relatively late, but it is the fastest-growing country in the world in ultra-precision machining technology.}

^{The development of ultra-precision machining in China.}

^{For a long period of time in the past, due to the embargo restrictions of Western countries, my country's import of foreign ultra-precision machine tools was severely restricted. However, when my country's own CNC ultra-precision machine tool was successfully developed in 1998, Western countries immediately lifted the ban on our country, and my country has now imported a number of ultra-precision machine tools.}

^{my country's Beijing Machine Tool Research Institute, Aviation Precision Machinery Research Institute (Aviation 303), Harbin Institute of Technology, National University of Defense Technology and other units are now able to produce several kinds of ultra-precision CNC diamond machine tools.}

^{Beijing Machine Tool Research Institute is one of the main units that conduct research on ultra-precision machining technology in China. It has developed a variety of different types of ultra-precision machine tools, components and related high-precision testing instruments, such as precision bearings with an accuracy of 0.025μm, JCS -027 ultra-precision lathe, JCS-031 ultra-precision milling machine, JCS-035 ultra-precision lathe, ultra-precision lathe CNC system, photosensitive drum processing machine tool for photocopier, infrared high-power laser mirror, ultra-precision vibration-displacement micrometer, etc. It has reached the domestic leading and international advanced level.}

^{NAM-800 nano CNC lathe is the latest generation of nano-scale machining machine tool of Beijing Machine Tool Research Institute. It is the perfect unity of today's numerical control technology, servo technology and mechanical manufacturing technology. This machine tool provides a good processing method for the most advanced scientific and technological development in my country.}

^{The Ministry of Aerospace Industry 303 has carried out in-depth research and product production in ultra-precision spindles, granite coordinate measuring machines, etc.}

^{Harbin Institute of Technology has carried out fruitful research on diamond ultra-precision cutting, crystal orientation and sharpening of diamond tools, and electrolytic on-line dressing technology of diamond micro-powder grinding wheels.}

^{Tsinghua University has conducted in-depth research on integrated circuit ultra-precision machining equipment, disk processing and testing equipment, micro-displacement table, ultra-precision abrasive belt grinding and polishing, ultra-precision grinding of diamond powder grinding wheels, and ultra-precision cutting of non-circular sections. Research, and corresponding products come out.}

^{In addition, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Huazhong University of Science and Technology, Shenyang No. 1 Machine Tool Factory, Chengdu Tool Research Institute, National University of Defense Technology, etc. have all conducted research in this field, and achieved remarkable results.}

^{But in general, there is still a considerable gap between China and foreign countries in terms of efficiency, accuracy, reliability, especially specifications (large size) and technical support of ultra-precision machining machine tools, compared with actual production requirements. . In addition, the precision machining of complex curved surfaces has always been a barrier to the development of my country's manufacturing industry, and the development of the manufacturing industry is related to the long-term development of the national economy, and a lot of research is still needed.}

^{The development trend of precision machining.}

^{1. High precision and high efficiency.}

^{High precision and high efficiency are the eternal themes of ultra-precision machining. In general, fixed abrasive processing continuously pursues the machining accuracy of free abrasive grains, while free abrasive grain processing continues to pursue the efficiency of fixed abrasive processing. Although the current ultra-precision processing technologies such as CMP and EEM can obtain extremely high surface quality and surface integrity, they are guaranteed at the expense of processing efficiency. Although ultra-precision cutting and grinding technology has high processing efficiency, it cannot obtain the processing accuracy such as CMP and EEM. It is the goal of researchers in the field of ultra-precision machining to explore a machining method that can take into account both efficiency and precision. The emergence of semi-fixed abrasive processing methods reflects this trend. On the other hand, it is the birth of composite processing methods such as electrolytic magnetic grinding and magnetorheological abrasive flow processing.}

^{2. Process integration.}

^{Today's competition among enterprises tends to be fierce, and high production efficiency has increasingly become a condition for enterprises to survive. In this context, there have been calls for "grinding instead of grinding" or even "grinding instead of throwing". On the other hand, there is a growing trend towards using one machine for multiple operations (eg turning, drilling, milling, grinding, finishing).}

^{3. Large-scale and miniaturized.}

^{In order to process large-scale optoelectronic devices (such as mirrors on large-scale astronomical telescopes) required in aviation, aerospace, aerospace and other fields, it is necessary to establish large-scale ultra-precision processing equipment. In order to process micro-devices (such as micro-sensors, micro-drive components, etc.) required in the fields of micro-electronic machinery and optoelectronic information, micro-ultra-precision machining equipment is required (but this does not mean that micro-miniature machining equipment is necessary for processing micro-miniature workpieces).}

^{Ultra-precision machining technology is ushering in a prosperous era. Great progress has been made in ultra-precision cutting, ultra-precision grinding, ultra-precision grinding and polishing technology. After processing, the surface accuracy of workpieces can reach nanometer or sub-nanometer level, and the processing methods are becoming more and more diversified. In the production and manufacture of flowmeter sensors, in order to achieve high-precision measurement of products, precision machining technology ensures the machining accuracy of products.}