Wed Jun 08 15:19:29 CST 2022
In terms of machining accuracy, in the past 10 years, the machining accuracy of ordinary CNC machine tools has increased from 10μm to 5μm, and the precision machining center has increased from 3~5μm to 1~1.5μm, and the ultra-precision machining accuracy has begun to enter the nanometer level ( 0.001μm). The improvement of machining accuracy lies not only in the use of ball screw pairs, hydrostatic guides, linear rolling guides, magnetic suspension guides and other components, which improve the control accuracy of the CNC system, and the application of high-resolution position detection devices, but also the use of various Error compensation technology, such as screw pitch error compensation, tool error compensation, thermal deformation error compensation, spatial error comprehensive compensation, etc.
In terms of processing speed, high-speed processing originated in the early 1990s. It is characterized by the application of electric spindle and linear motor, which greatly increases the spindle speed. The feed speed reaches 60m/min or more, and the feed acceleration and deceleration reach 1~ Above 2g, the spindle speed can reach above 100000r/min. High-speed feed requires the numerical control system to have a fast calculation speed and a short sampling period. It also requires the numerical control system to have sufficient advance path acceleration (deceleration) optimization preprocessing capabilities (forward processing), and some systems can process 5000 blocks in advance. In order to ensure the processing speed, the high-end CNC system can change the feed rate 2000 to 10000 times per second.
With the development of CNC machine tools towards functional integration, it is more reflected in: automatic workpiece loading and unloading, automatic positioning of workpieces, automatic tool setting, automatic workpiece measurement and compensation, and the "universal" integrating drilling, turning, boring, milling and grinding "Processing" and "complete processing" that integrates loading, unloading, processing, and measurement.
With the continuous penetration and development of artificial intelligence in the computer field, numerical control systems are developing in the direction of intelligence. In the new generation of numerical control systems, due to the adoption of control mechanisms such as "Evolutionary Computation", "Fuzzy System" and "Neural Network", the performance is greatly improved, and the processing process is adaptive Control, automatic load identification, self-generation of process parameters, dynamic compensation of motion parameters, intelligent diagnosis, intelligent monitoring and other functions.
The current advanced CNC system provides users with powerful networking capabilities. In addition to the RS232C interface, it also has a DNC interface with remote buffering function, which can realize data communication between multiple CNC machine tools and directly control multiple CNC machine tools. Some have been equipped with the function of communicating with the industrial local area network and the network interface, which has promoted system integration and information integration, and made remote online programming, remote simulation, remote operation, remote monitoring and remote fault diagnosis possible.
The structure of the parallel machine tool is simple but the mathematics is complicated. The movement of the entire platform involves considerable mathematical operations, so the parallel machine tool is a knowledge-intensive mechanism. Compared with traditional tandem machine tools, parallel machine tools have the advantages of high rigidity, high carrying capacity, high speed, high precision, light weight, simple mechanical structure, low manufacturing cost, and high degree of standardization. They have been successfully applied in many fields.