New advances in precision and ultra-precision machining technology (3)

3.3 New Diamond Tool Crystal Orientation Method Due to the extremely high hardness of the diamond and the anisotropy of the crystal, the sharpening of the single crystal diamond tool is extremely difficult. The orientation of the crystal is required for the manufacture of diamond tools and sharpening. In the past, the crystal orientation method mainly used X-ray crystal orientation, the instrument was expensive, and the orientation operation was rather cumbersome. Harbin Institute of Technology has successfully developed a new laser crystal orientation method. The equipment used is simple, and the orientation operation is convenient, which can greatly simplify the orientation of diamond crystal.

4. Progress in ultra-Precision Machining machines

4.1 Development of foreign ultra-precision machine tools The development of ultra-precision machine tools is an important prerequisite for the development of ultra-precision machining. In recent years, developed countries have successfully developed a variety of advanced ultra-precision machining machines. The development direction of ultra-precision machine tools is to further improve the precision of ultra-precision machine tools, develop large-scale ultra-precision machine tools, and develop multi-functional and high-efficiency special ultra-precision machine tools.

In the 1970s (Japan in the 1980s), the United States, Britain, Germany and other countries began to produce ultra-precision machine tools and were available in volume. In the field of large-scale ultra-precision machine tools, the LLL National Laboratory in the United States successfully developed two large-scale super-fine diamond lathes in 1986: one for the horizontal DTM-3 diamond lathe with a diameter of 2.1m and the other with a processing diameter of 1.65m. LODTM vertical large optical diamond lathe. Among them, LODTM vertical large-scale optical diamond lathe is recognized as the world's most accurate ultra-precision machine tool. The United States later developed a large 6-axis Cnc Precision grinding machine for precision grinding of large optical mirrors.

In 1991, the Cranfield Precision Machining Center in the UK successfully developed the OAGM-2500 multi-function three-coordinate linkage CNC grinding machine (table area 2500mm × 2500mm), which can be machined (grinding, turning) and measuring precision free-form surfaces. The machine tool uses a workpiece splitting method to process a large mirror with a diameter of 7.5 m in an astronomical telescope.

Japan's multi-functional and high-efficiency dedicated ultra-precision machine tools have developed rapidly, and have played a very good role in promoting the development of the Japanese microelectronics and home appliance industry.

4.2 The development of ultra-precision machine tools in China has been in the past for a long period of time. Due to the embargo restrictions imposed by Western countries, China's import of foreign ultra-precision machine tools is severely limited. However, after the successful development of China's own CNC super-precision machine tools in 1998, Western countries immediately opened a ban on China. China has now imported several ultra-precision machine tools.

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