China's numerical control industry cannot rest on its laurels. It should seize the opportunity to continue to develop, strive to develop its own advanced technology, increase technological innovation and personnel training, improve the comprehensive service capabilities of enterprises, and strive to shorten the gap with developed countries. Strive to realize the transformation of CNC machine tool products from low-end to high-end, from primary product processing to high-precision product manufacturing as soon as possible, and realize the transformation from Made in China to Created in China, and from a manufacturing power to a manufacturing power.
High speed
With the rapid development of industries such as automobiles, national defense, aviation, and aerospace, and the application of new materials such as aluminum alloys, the requirements for high-speed processing of CNC machine tools are getting higher and higher.
High precision
The precision requirements of CNC machine tools are now not limited to static geometric precision, and more and more attention has been paid to the movement precision, thermal deformation and vibration monitoring and compensation of machine tools.
(1) Improve the control precision of the CNC system: adopt high-speed interpolation technology, realize continuous feed with small program segments, refine the CNC control unit, and use high-resolution position detection devices to improve position detection accuracy (Japan has developed a 106 pulses/rotation AC servo motor with built-in position detector, its position detection accuracy can reach 0.01μm/pulse), the position servo system adopts feedforward control and nonlinear control methods;
(2) Adopting error compensation technology: adopting technologies such as backlash compensation, screw pitch error compensation and tool error compensation to comprehensively compensate the thermal deformation error and space error of the equipment. The research results show that the application of comprehensive error compensation technology can reduce the machining error by 60% to 80%;
(3) Use the grid to check and improve the motion trajectory accuracy of the machining center, and predict the machining accuracy of the machine tool through simulation to ensure the positioning accuracy and repeat positioning accuracy of the machine tool, so that its performance is stable for a long time, and it can complete multiple tasks under different operating conditions. Various processing tasks and ensure the processing quality of pa
Compound function
The meaning of compound machine tool refers to the realization or as far as possible completion of the processing of various elements from blank to finished product on one machine tool. According to its structural characteristics, it can be divided into two types: process compound type and process compound type. Process compound machine tools such as boring-milling-drilling compound-machining center, turning-milling compound-turning center, milling-boring-drilling-turning compound-compound machining center, etc.; process compound machine tools such as multi-faceted multi-axis linkage processing compound machine tools and double spindles Turning centers, etc. The use of compound machine tools for processing reduces the auxiliary time for loading and unloading workpieces, changing and adjusting tools, and errors in the intermediate process, improves the machining accuracy of parts, shortens the product manufacturing cycle, and improves production efficiency and the manufacturer's market response ability. Compared with the traditional production method with decentralized process, it has obvious advantages.
The compounding of the machining process has also led to the development of machine tools to modularization and multi-axis. The latest turning machining center launched by German Index company is a modular structure. The machining center can complete various processes such as turning, milling, drilling, gear hobbing, grinding, laser heat treatment, etc., and can complete all processing of complex parts. With the continuous improvement of modern machining requirements, a large number of multi-axis linkage CNC machine tools are more and more welcomed by major enterprises. At the 2005 China International Machine Tool Exhibition (CIMT2005), domestic and foreign manufacturers exhibited various forms of multi-axis processing machine tools (including double spindles, double tool holders, 9-axis control, etc.) Five-axis high-speed portal machining centers, five-axis linkage high-speed milling centers, etc.
High reliability
Compared with traditional machine tools, CNC machine tools have increased the CNC system and corresponding monitoring devices, etc., and applied a large number of electrical, hydraulic and electromechanical devices, which is easy to increase the probability of failure; Reliability is extremely unfavorable, and the parts processed by CNC machine tools are relatively complex, and the processing cycle is long, requiring an average time between failures of more than 20,000 hours. In order to ensure the high reliability of CNC machine tools, it is necessary to carefully design the system, strictly manufacture and clarify the reliability goals, and analyze the failure mode and find out the weak link through maintenance. The average trouble-free time of foreign CNC systems is more than 70,000 to 100,000 hours, and the average trouble-free time of domestic CNC systems is only about 10,000 hours. The average trouble-free working time of foreign complete machines is more than 800 hours, while the domestic maximum is only 300 hours.
