Talking about the future development of CNC lathes in machining industry
At present, the development of automated CNC lathes is changing with each passing day. High speed, high precision, compounding, intelligence, openness, parallel drive, networking, extremes, and green have become the development trend and direction of CNC machine tools. As a large manufacturing country, China still relies mainly on its comparative advantages in labor, price, and resources. However, it still has a large gap with its foreign counterparts in terms of product technological innovation and independent development. China's CNC industry cannot rest on the status quo. It should seize the opportunity to continue to develop, strive to develop its own advanced technology, increase technical innovation and personnel training, improve the comprehensive service capabilities of enterprises, and strive to reduce the gap with developed countries. Strive to realize the early transformation of CNC machine tool products from low-end to high-end, from primary product processing to high-precision product manufacturing, and realize the transformation from Chinese manufacturing to Chinese creation, and from a manufacturing country to a manufacturing country.
With the rapid development of automotive, national defense, aviation, aerospace and other industries and the application of new materials such as aluminum alloys, the requirements for the high-speed processing of automated CNC lathes are becoming higher and higher.
(1) Spindle speed: The machine tool uses an electric spindle (built-in spindle motor), and the spindle speed reaches 200000r / min;
(2) Operation speed: The rapid development of microprocessors has provided a guarantee for the development of high-speed and high-precision CNC systems. CPUs have been developed to 32-bit and 64-bit CNC systems, and the frequency has been increased to several hundred megahertz and thousands. megahertz. Due to the greatly improved computing speed, when the resolution is 0.1μm, 0.01μm, it can still obtain a feed speed of up to 24-240m / min;
(3) Feed rate: When the resolution is 0.01 μm, the feed rate reaches 240 m / min and accurate processing of complex profiles can be obtained;
(4) Tool changing speed: At present, the tool exchange time of foreign advanced machining centers is generally around 1s, and the high is 0.5s. The German Chiron company designed the tool magazine into a basket style with the main axis as the axis and the tools arranged in a circle. The tool-to-tool change time was only 0.9s.
The requirements for the accuracy of automatic CNC lathes are no longer limited to static geometric accuracy, and the machine tool's kinematic accuracy, thermal deformation, and monitoring and compensation of vibration have been paid more and more attention.
(1) Improve the accuracy of CNC system control: Adopt high-speed interpolation technology to achieve continuous feed with small program segments, refine the CNC control unit, and use high-resolution position detection devices to improve the accuracy of position detection. AC servo motor with built-in position detector of 106 pulses / revolution, its position detection accuracy can reach 0.01μm / pulse). Position servo system adopts methods such as feedforward control and non-linear control;
(2) Automatic CNC lathes use grid inspection and improve the trajectory accuracy of the machining center, and predict the machining accuracy of the machine tool through simulation to ensure the positioning accuracy and repeated positioning accuracy of the machine tool, making its performance stable for a long time and able to operate under different operating conditions Complete a variety of processing tasks and ensure the processing quality of parts.
(3) Adopting error compensation technology: adopting 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 processing errors by 60% to 80%;