The operation contents and actions that need to be considered and decided by the operator are compiled into NC machining programs according to the specified code format and recorded on the control medium. During machining, the code information on the control medium is input into the control system of the CNC machine tool. The control system calculates and controls the input information, and continuously sends pulse signals to the servo mechanism of the machine tool to directly direct the movement of the machine tool. The servo mechanism converts and amplifies it, and then a driving device and a transmission mechanism drive the machine tool to move according to the programmed program, thus automatically machining the parts we need. CNC machining technology mainly includes the following aspects:

1) Select and determine the content of NC machining through part drawing analysis;

2) Combined with the characteristics of the machined surface and the functions of the numerical control equipment, the process analysis of parts numerical control machining is carried out;

3) Industrial design of NC machining;

4) According to the needs of programming, the part drawing is mathematically processed and calculated;

5) prepare a processing program sheet;

6) making control media according to the program list;

7) Check and modify the processing program;

8) Carry out trial processing on the first piece, further modify the processing procedure, and deal with the problems on site.

9) Prepare the technical documents of NC machining process.

1.2.2 technological characteristics of NC machining

Compared with ordinary machine tool machining, NC machining follows the same principle in many aspects. However, due to the high degree of automation of CNC machine tools, different control methods and high equipment cost, the response of CNC machining process has the following characteristics.

1) process is very specific.

2) The process design is very strict.

3) Pay attention to the adaptability of processing

1.2.3 process adaptability of NC machining

According to the characteristics of NC machining, parts can be generally divided into the following three categories according to the degree of process adaptability:

Me, the most suitable class.

1) Parts with complex shapes and high machining accuracy, which cannot be machined by general equipment or can be machined but cannot guarantee quality;

2) Complex curve or surface contour parts described by mathematical model;

3) Shell or box parts that are difficult to measure, control feed or control size;

4) Parts with multiple processes, such as multiple processes, must be combined in one clamping;

Two. Adaptability grade

1) Parts that are easily disturbed by human factors when processed on general machine tools have low value, but out-of-control quality will cause greater economic impact;

2) Machining parts with complex special tools on ordinary machine tools;

3) The part that needs to be revised many times before it can be finalized;

4) Machining parts that need to be adjusted for a long time on ordinary machine tools;

5) Parts with low productivity or high physical labor intensity when processed by general machine tools;

Three. Inadaptive class

1) produces large quantities of parts;

2) Parts that are difficult to clamp or rely entirely on positioning to ensure machining accuracy;

3) The machining allowance is very unstable, and there is no online detection system that can automatically adjust the coordinate system of parts on the CNC machine tool;

4) Parts that must be processed with specific process equipment;

After NC machining of the above parts, the production efficiency and economy are generally not significantly improved, but more.

It may be self-defeating or not worth the loss, so it should not be used as the choice of NC machining.

1.3 Composition of NC machining process