This paper gives a general overview of NC technology.
1. The 52-year development of NC technology has mainly gone through six main stages: electronic tube numerical control system, transistor numerical control system, integrated circuit numerical control system, minicomputer numerical control system, microprocessor numerical control system and general CNC system based on industrial PC.
2. The principle of NC machine tool processing is: first, digitize the drawing and process information of the machined parts, and write the processing program with the prescribed code and program format; then input the programming instructions into the NC device of the machine tool; then, the NC device decodes and calculates the program (code) to each machine tool. The coordinate servo mechanism and auxiliary control device send out signals to drive the moving parts of the machine tool, control the auxiliary movement needed, and finally process qualified parts.
3. NC machine tool is mainly composed of seven parts: processing program, input device, NC system, servo system, measurement feedback device, auxiliary control device and machine tool.
4. CNC machine tools can be divided into cutting machine tools, forming machine tools, special machine tools and other machine tools according to the processing methods; CNC machine tools can be divided into point control, point linear control and contour control according to the control system functions; CNC machine tools can be divided into open-loop, closed-loop and semi-closed-loop control according to the servo control mode. According to the function level of CNC system, it can be divided into three grades: high, medium and low CNC machine tools.
5. NC machine tools have higher technical requirements for operators and maintenance personnel, and higher requirements for tool fixtures. CNC machine tools are mainly suitable for parts produced in small batches and many times, parts with complex geometry, parts that must be processed in a variety of ways, parts that must be strictly controlled in tolerance, parts whose process design will change, and parts that need to be inspected all.
6. There are many CNC systems used in the market. When programming, it should be programmed according to the programming rules of the CNC system code used.