CNC machining refers to a process method for processing parts on CNC machine tools. The process regulations of CNC machine tool processing and traditional machine tool processing are generally consistent, but significant changes have also taken place. A machining method that uses digital information to control the displacement of parts and tools. It is an effective way to solve the problems of variable parts, small batches, complex shapes, and high precision, and to achieve high-efficiency and automated processing.
General CNC machining usually refers to computer digital control precision machining, CNC machining lathe, CNC machining milling machine, CNC machining boring and milling machine, etc.
Numerical control processing refers to the processing in which the control system issues instructions to make the tool perform various movements that meet the requirements, and expresses the shape and size of the workpiece in the form of numbers and letters, as well as processing requirements. It generally refers to the process of processing parts on CNC machine tools.
A CNC machine tool is a machine tool controlled by a computer. The computer used to control the machine tool, whether it is a special computer or a general-purpose computer, is collectively called a CNC system. The movement and auxiliary actions of the CNC machine tool are controlled by the instructions issued by the CNC system. The instructions of the numerical control system are compiled by the programmer according to the material of the workpiece, the processing requirements, the characteristics of the machine tool, and the instruction format (numerical control language or symbols) prescribed by the system. The numerical control system sends out operation or termination information to the servo device and other functional components according to the program instructions to control various movements of the machine tool. When the part processing program ends, the machine tool will automatically stop. For any kind of CNC machine tool, if there is no program command input in its CNC system, the CNC machine tool cannot work. The controlled actions of the machine tool roughly include the start and stop of the machine tool; the start and stop of the spindle, the transformation of the rotation direction and the speed; the direction, speed, and mode of the feed movement; the selection of the tool, the compensation of the length and the radius; the replacement of the tool, and the cooling The opening and closing of the liquid.
CNC advantages and disadvantages
CNC machining has the following advantages:
① The number of tooling is greatly reduced, and complex tooling is not required for processing parts with complex shapes. If you want to change the shape and size of the part, you only need to modify the part processing program, which is suitable for new product development and modification.
②The processing quality is stable, the processing precision is high, and the repetition precision is high, which is suitable for the processing requirements of the aircraft.
③The production efficiency is higher in the case of multi-variety and small-batch production, which can reduce the time of production preparation, machine tool adjustment and process inspection, and reduce the cutting time due to the use of the best cutting amount.
④ It can process complex profiles that are difficult to process by conventional methods, and even process some unobservable processing parts.
The disadvantage of CNC machining is that the cost of machine tool equipment is expensive and requires a high level of maintenance personnel.
There are manual (manual) programming and automatic programming methods for NC machining programming. Manual programming, the entire content of the program is manually written in accordance with the instruction format specified by the CNC system. Automatic programming is computer programming, which can be divided into automatic programming methods based on language and drawing. However, no matter what kind of automatic programming method is adopted, corresponding hardware and software are required.
It can be seen that the realization of NC machining programming is the key. But programming alone is not enough. CNC machining also includes a series of preparatory work that must be done before programming and the aftermath of programming. Generally speaking, the main contents of CNC machining process are as follows:
⑴ Select and confirm the parts and contents for CNC machining;
⑵ Process analysis of CNC machining of parts drawings;
⑶ Process design of CNC machining;
⑷ Mathematical processing of parts drawings;
⑸ Compile the processing procedure list;
⑹ Make the control medium according to the procedure list;
⑺ Check and modify the program;
⑻ Trial processing of the first piece and on-site problem handling;
⑼The finalization and filing of CNC machining process documents.