Since the advent of CNC machining technology, it has brought revolutionary changes to the machinery manufacturing industry. CNC machining technology has become the technical basis for the realization of automation, flexibility and integrated production in the manufacturing industry. Modern CAD / CAE / CAPP / CAM, FMS, CIMS, agile manufacturing and intelligent manufacturing and other advanced manufacturing technologies are all based on CNC machining technology. It is not only an indispensable material means to improve product quality and labor productivity, but also an "enabling technology" for the existence or development of various modern emerging technologies or cutting-edge technologies. Its technical level has become an important symbol to measure the level of a country's industrial modernization.
The basic principle of CNC machining is to decompose the composite motion of the tool/workpiece that generates the workpiece into the component motion of the machine tool motion coordinates, and the relative motion of the tool/workpiece is automatically realized by the program control, and the processing of the workpiece will be completed according to the specified processing sequence.
The function of the point control system is to move the machine tool table or spindle to a specified position, so as to realize the processing operation at this position. Its motion path and speed are secondary, while ensuring the accuracy of reaching a predetermined position is primary.
The linear cutting control system can make the tool move along a path parallel to the main coordinate movement direction of the machine tool at a control speed suitable for the cutting of CNC machining. It is the simplest continuous contour control method, and its numerical control motion coordinates are single-axis control which can not simultaneously control the motion of two or more coordinates, so it cannot complete the combination of simultaneous motion in several coordinate directions.
Contour control is a complex, flexible and expensive control method of machine tool, which can complete point control and linear cutting control. The most characteristic of the CNC system is that it can control the movement of more than one axis at the same time. And the movement path of the tool can be continuously controlled. It is a control system that can obtain the required geometric profile, precision and surface quality on the workpiece surface by synthetic motion.
CNC machining programming is to change the process, process parameters, tool displacement, displacement direction and other auxiliary actions (tool selection, cooling opening and closing, workpiece clamping and loosening, etc.) according to the design drawings of the parts. The program sheet is compiled and processed according to the motion sequence and the coordinate system, instruction code and format specified by the CNC system used. After checking and trial cutting, it is the process of completing a series of instructions for the specified processing tasks, which is called CNC machining programming. It is the whole process starting from the analysis of part drawings and process requirements to the inspection of the large program until it is qualified.