High precision is the mainstream trend of CNC machine tools

“The development and manufacturing technology of ultra-precision machine tools is a cutting-edge technology that will lead the machining precision of machine tools to the technical field that humans have not touched. The application field of ultra-precision machine tool technology has been extended to many aspects of our daily life. And is enriching and changing our lives." Liu Bingye, director of the Beijing Machine Tool Research Institute, pointed out at the 2014 China Machine Tools Development High-end Forum held on June 19, "When we are full of manufacturing complex processing equipment, we It should be known that there is a rare type of machine tool that is rarely found in industry exhibitions, but it is a machine tool that is highly valued and controlled by developed countries. This is an ultra-precision machine tool, and ultra-precision machine tools embody the competitiveness of a national precision technology. ”

High precision is the mainstream trend of CNC machine tools

“In the past 30 years, the world's machine tool technology has been greatly developed, and the development trend of machine tool technology has also shown diversified characteristics, such as high-precision trend, high-speed motion trend, multi-motion axis trend. High reliability trends, multi-functional composite trends, reconfigurable trends, low energy consumption and environmental trends, and intelligent trends, but among all trends, the trend that best reflects the mainstream of development should be high precision and The trend of intelligence.” Liu Bingye emphasized that high precision is the mainstream development trend of CNC machine tools, and the precision of ultra-precision machining is an order of magnitude higher than that of precision machining.

In fact, the technical fields involved in ultra-precision machining technology are very rich. In the course of more than 30 years of research at the Beijing Machine Tool Research Institute, Liu Bingye systematically summed up 36 key frontier research and 11 leading core technologies for the related technologies involved in ultra-precision machining technology. Among them, key frontier research includes design, moving parts, measurement analysis, process technology, host manufacturing technology and machine tool application conditions. Leading core technologies include: precision ultra-precision spindle key structure manufacturing technology, precision ultra-precision linear motion component key structure manufacturing technology, high-resolution motion drive technology, machining process manufacturing technology for machine tool key components, and feature technology for components to resist external interference Structure and manufacturing technology for high-stability fast linear motion, nested structure design technology for multi-motion axis machine tools, and machine tool integrated manufacturing technology for target parts manufacturing.

“In the development process of machine tool precision from micron to nanometer, there are three key technologies that cannot be avoided. These three technologies are also the research threshold for nano precision machine tools.” Liu Bingye said that one of the technologies is bearing technology without hysteresis. Hysteresis exists in a large number of mechanical systems. Hysteresis not only seriously affects the motion positioning accuracy and repeatability of the machine slide, but also affects the high-resolution realization of motion, and also affects the machining shape accuracy and surface roughness of precision parts. . The hydrostatic bearing technology can solve the phenomenon of mechanical hysteresis well, and can homogenize the geometric error, which is widely used in ultra-precision machine tools. Static pressure technology has made significant progress over the past decade, and self-compensating feedback technology is more mature. The flow-controlled throttling technology greatly increases the rigidity of the hydrostatic bearing, and the hardness of the material processed by the ultra-precision machine tool is continuously improved.

The other two key technologies are high-resolution drive technology and micro-vibration processing technology in mechanical systems. Nano-scale resolution is a feature of the performance of ultra-precision machine tools in the past decade, and there are many factors influencing sports. At the same time, a large number of experimental studies have found that vibration signals of the order of 10 nanometers exist in many mechanical actuators, causing interference with the execution and measurement of mechanical sensitivity, which is called microvibration. "In-depth study of the mechanism of micro-vibration and seeking solutions is the only way for ultra-precision machine tools to reach nano-precision." Liu Bingye said.

Meet the application needs of ultra-precision technology

"China's aerospace remote sensing, laser nuclear fusion, defense weapon systems, astronomical detection and other advanced technology fields, the demand for large-aperture aspheric optical components is increasing, but some foreign high-end optical processing equipment and technology imposes an embargo on China. The research work on the processing technology of large-diameter aspherical parts in China has been carried out, but the maturity is still low. At the same time, the processing precision of the equipment developed by ourselves is lower than that of foreign countries, the effective unit of the superior units is insufficient, and there is still a large diameter. The combination of optical parts processing and ultra-precision processing technology is relatively low." Jiang Zhuangde, an academician of the Chinese Academy of Engineering, also proposed an urgent need for ultra-precision machining and measurement technology and equipment in China.

Jiang Zhuangde Jianyan, in the future, China's ultra-precision processing technology should solve the digital processing technology of large-diameter aspherical parts, improve the core competitiveness and overall technical level of China's optical processing field, solve the embargo problem and replace imports. For example, for an ultra-precision milling machine with a diameter of 900 mm, the project is a key project in the advanced manufacturing technology field of the “Eleventh Five-Year” National 863 Program, which mainly addresses the ultra-precision manufacturing of large optical devices such as aerospace and laser nuclear fusion.

For the future application of ultra-precision machine tools, Liu Bingye said that hard turning and hard milling will be widely used, and light hard turning will replace grinding. Ultra-precision machine tool technology is suitable for processing automotive parts, bearing rings, injection molds, hydraulic valves, balls, screws, nuts, etc., can be used for high-precision turning of stainless steel, cast iron, plastic, graphite, green ceramics and other materials. “The application of ultra-precision machine tool technology can greatly improve productivity and precision. The machining efficiency and surface quality of some automotive parts will be better than grinding. Because it can be dry-cut, it will be more environmentally friendly. In addition, ultra-precision machine tool technology is applied to hard cutting. The machine tool will greatly increase the life of the machine tool."

Previously, Beijing Machine Tool Research Institute and British Taylor Hobson Co., Ltd. jointly established a joint laboratory in Beijing Industrial Research Co., Ltd. to establish a win-win mechanism through joint laboratories to promote the long-term research and service of both parties in the field of measurement and testing. development of. Not only through joint research and cooperation projects, but also through joint laboratories to provide a platform for both parties to carry out various business services.

Liu Bingye said that in the future, Beijing Machine Tool Research Institute will rely on two state-level ultra-precision engineering research centers, and use the platform of precision ultra-precision CNC machine tool innovation capability as the basic organization mode to accelerate the formation of a larger alliance of precision ultra-precision machine tools. Industrialization process to expand market share. “In the next five years, we have the confidence and ability to push ultra-precision machine tool technology to new heights.”