With the development of science and technology, the shape and structure of mechanical products continue to improve, and the requirements for the quality of parts processing are also getting higher and higher. Especially with the rise and maturity of FMS and CIMS, higher requirements have been put forward for machine tool numerical control systems, and modern numerical control machining is developing in the direction of high-speed, high-precision, high reliability, high flexibility, high integration, networking and intelligence. First, high speed It can be realized through high-speed computing technology, fast interpolation computing technology, ultra-high-speed communication technology and high-speed spindle technology. Second, high precision High precision has always been the goal of the development of CNC machine tool technology. It includes the geometric accuracy of machine tool manufacturing and the machining accuracy of machine tool use. To improve the machining accuracy of CNC machine tools, it is generally achieved by reducing the error of CNC system, improving the structural characteristics and thermal stability of CNC machine tools, and using compensation technology and auxiliary measures. In terms of reducing the error of the CNC system, it is usually used to improve the resolution of the CNC system, refine the CNC control unit, improve the position detection accuracy, and in the position servo system to improve the response characteristics of the servo system, the use of feedforward and nonlinear control methods. In the use of compensation technology, the use of backlash compensation, screw nut error compensation, tool compensation, thermal deformation error compensation and space error compensation. It is predicted that the ultra-precision machining will enter the nanometer (0.01μm) era in the 21st century. Third, high reliability The reliability of CNC machine tool is a key index of product quality. An important quantitative index to measure reliability is the Mean Time Between Failures (MTBF), now the MTBF of the CNC machine tool has reached more than 800h, and the MTBF of the CNC system has reached more than 125 months. To improve the reliability of numerical control system, redundancy technology, fault diagnosis technology, automatic error detection, error correction technology, system recovery technology, software reliability technology and other technologies can be used. At present, many enterprises are in the reliability design technology, reliability test technology, reliability evaluation technology, reliability growth technology and reliability management and reliability assurance system for in-depth research and wide application, in order to expect to improve the reliability of CNC machine tools to a new level. Fourth, high flexibility Flexibility refers to the ability of the machine tool to adapt to the change of the processing object. At present, while further improving the single-machine flexible automatic processing, efforts are being made to develop towards unit flexibility and system flexibility, such as FMC and FMS, which reflect system flexibility, are developing rapidly. As the brain of CNC machine tools - CNC system, in the 21st century will have the maximum flexibility, can achieve a variety of uses, specifically refers to the open system structure. Through reconfiguration and editing, the composition of the system can be large or small according to the need; The function can be dedicated or universal, the function price is adjustable; It can integrate the technical know-how of users to form brand-name products. 5. High integration CNC system and machining process as a whole, to achieve electromechanical optoacoustic integrated control; Measurement modeling, processing integration; Integration of processing, real-time detection and correction; Machine tool host design and CNC system design integration. 6. Networking To achieve a variety of communication protocols, not only meet the needs of single machine, but also meet the requirements of FMC, FMS, CIMS on the basic equipment, and facilitate the formation of a "global manufacturing" basic unit. 7. Intelligence The CNC system of the 21st century will be a highly intelligent system, which specifically means that the system should realize self-adaptation, self-diagnosis and self-adjustment of the processing process in part or all; The multimedia man-machine interface is easy for users to operate, and intelligent programming makes programming more intuitive. It can not only use a variety of high-level languages to program, but also use natural language programming. Self-generating and intelligent database of processing data; Intelligent monitoring, etc.