The level of a lathe machine tool, it depends on its repeated positioning accuracy. If the repeated positioning accuracy of a machine tool can reach 0.005mm (ISO standard. Statistical method), it is a high-precision machine tool, which is within 0.005mm (ISO standard. , statistical method) below, is ultra-high-precision machine tools, high-precision machine tools, must have the best bearings and screws.
When it comes to the “precision” of CNC machine tools, it is necessary to clarify the definitions and calculation methods of standards and indicators.
Japanese machine tool manufacturers usually use the JISB6201 or JISB6336 or JISB6338 standards when specifying “accuracy”. JISB6201 is generally used for general-purpose machine tools and ordinary CNC machine tools,
JISB6336 is generally used for machining centers, and JISB6338 is generally used for vertical machining centers. The above three standards are basically the same in defining position accuracy,
The article only uses JIS B6336 as an example, because on the one hand, this standard is relatively new, and on the other hand, it is slightly more precise than the other two standards.
European machine tool manufacturers, especially German manufacturers, generally use the VDI/DGQ3441 standard.
American machine tool manufacturers usually use the NMTBA (National Machine Tool Builder’s Assn) standard (this standard is derived from a study by the American Machine Tool Builders Association, promulgated in 1968, and later revised).
The standards mentioned above are all related to ISO standards.
The dimensional accuracy and shape and position accuracy of typical parts processed by the machining center are compared with the domestic and foreign levels. The domestic level is roughly 0.008-0.010mm, while the international advanced level is 0.002-0.003mm.
Although the development of my country’s machine tool manufacturing industry has fluctuated, it has always paid more attention to CNC technology and CNC machine tools, and has strong market competitiveness.
However, in terms of medium and high-end CNC machine tools, there is still a big gap with some foreign advanced products and technology development, and most of them are in the technology tracking stage. Ultra-precision machining currently refers to the size and position accuracy of 0.01 ~ 0.3μm, shape and contour. The accuracy is 0.003～0.1μm, the surface roughness of steel parts Ra≤0.05μm,
Copper parts Ra≤0.01μm. The ultra-precision CNC lathes and CNC milling machines developed in China have been put into production. At present, it is necessary to develop ultra-precision grinding machines and ultra-precision compound processing machine tools in terms of varieties, and at the same time, it is necessary to further improve the performance of ultra-precision spindle units, ultra-precision guide rail sub-units, ultra-precision smooth drive systems, ultra-precision contour control technology and nano-resolution CNC systems. performance and speed up its engineering.
Ultra-precision machine tools are mainly used to solve the ultra-precision machining of domestic high-tech and national defense key products. Although the demand is not large, it is a sensitive technology that is blocked by foreign technology.
On the other hand, the in-depth research of ultra-precision machining technology and the extension of its results will help the development and industrialization of high-precision machine tools that require a large amount of machining accuracy at the sub-micron level.