What is the basic process of CNC machining?

What is the basic process of CNC machining?

What is the basic process of CNC machining? Let's take a brief look together.

CNC machining refers to the process of machining parts on CNC machine tools. A digital control machine is a machine controlled by a computer, whether it is a specialized computer or a general-purpose computer, it is called a digital control system. The motion and auxiliary motion of the digital control machine are controlled by commands issued by the CNC system. The commands of the CNC system are written by programmers based on the material of the workpiece, processing requirements, characteristics of the machine tool, and the command format (CNC language or symbols) specified in the system. The digital control system sends execution or termination information to the servo device and other functional components based on program instructions to control various movements of the machine tool. After the machining process of the parts is completed, the machine tool will automatically stop. No matter what type of numerical control machine it is, if program commands are not entered into that CNC system, the numerical control machine cannot work.

The controlled motion of a machine tool usually includes the start and stop of the machine tool. Spindle start and stop, rotation direction and speed conversion; The direction, speed, and method of conveying motion; Tool selection, length and radius compensation, tool replacement, coolant on/off, etc.

There are two methods for programming CNC machining: manual (manual) programming and automatic programming. Manual programming, the entire content of the program is manually written according to the command format specified in the CNC system. Automatic programming is computer programming, which can be divided into language and image based automatic programming methods. However, regardless of which automatic programming method is used, corresponding hardware and software are required. As you can see, implementing CNC machining programming is crucial. But programming alone is not enough. CNC machining also includes a series of preparatory work before programming and post-processing work after programming. Generally speaking, the technology of CNC machining mainly includes the following contents:

(1) Select and determine the parts and content for NC machining.

(2) Analysis of CNC machining process for part drawings;

(3) Process design for CNC machining;

(4) Mathematical processing of part drawings;

(5) Develop a list of machining procedures.

(6) Create control media according to the program.

(7) Verification and modification of the program;

(8) First trial handling and on-site problem handling;

(9) Finalization and archiving of CNC machining process documents.

The characteristics of CNC machining pose two basic requirements for fixtures. One way is to ensure that the coordinate direction of the fixture is fixed relative to the coordinate direction of the machine tool. The second is to adjust the dimensional relationship between the parts and the machine coordinate system. In addition, the following considerations should also be taken into account:

When the processing volume of parts is not large, combination fixtures, adjustable fixtures, and other conventional fixtures should be used as much as possible to shorten production preparation time and save production costs.

2. Consider using specialized fixtures for mass production and strive for a simple structure.

3. The loading and unloading of parts is fast, convenient, and reliable, which can reduce the downtime of the machine.

4. The components of the fixture should not interfere with the surface processing of the machine's parts. That is to say, when the fixture is opened, the positioning and clamping mechanism components have no impact on the tool path being processed (such as collision).

Precision machining