CNC machining process design

The design of the numerical control processing route must be fully considered. Attention should be paid to the correct division of the process, the rational arrangement of the sequence, and the convergence of the numerical control machining process and the ordinary process.

1. Division of processes

Compared with the processing of CNC machine tools and ordinary machine tools, the machining process is more concentrated. According to the processing characteristics of CNC machine tools, the division of machining processes can be done in the following ways:

1) According to the clamping positioning division process

This method is generally adapted to the processing of a small number of parts, mainly the processing site is divided into several parts, each process processing part of it. For example, when machining the shape, the inner cavity is used for clamping; when the inner cavity is machined, the outer shape is clamped.

2) Divide the process by the tool used

In order to reduce the number of tool changes and idle time, you can use the principle of tool concentration to divide the process, use a knife in a fixture to complete all processing parts that can be processed, and then change the second knife to process other parts. This method is mostly used on special CNC machine tools or machining centers.

3) Dividing processes by rough and fine processing

For parts that are prone to machining deformation, taking into account the machining accuracy, deformation and other factors of the workpiece, the process can be divided according to the principle of rough and fine processing separation, that is, after the first rough finish.

In the process division, it is necessary to be flexible in accordance with the structural requirements of the workpiece, the installation method of the workpiece, the processing technology of the workpiece, the performance of the CNC machine tool, and the factory production organization and management, and strive to be reasonable.

2. Arrangement of processing sequence

The arrangement of the processing sequence shall be based on the structure of the workpiece and the condition of the blank, and the positioning and installation of the workpiece shall be selected to ensure that the rigidity of the workpiece is not destroyed and the deformation is minimized. Therefore, the arrangement of the processing sequence shall follow the following principles:

1) The processing of the previous process cannot affect the positioning and clamping of the next process

2) Processing the outer contour of the workpiece after machining the inner cavity of the workpiece first

3) Minimize repeat positioning and tool change times

4) In a multi-step process of installation and processing, the process of rigidly destroying the workpiece is arranged first.

3. The connection between CNC machining process and common process

As the NC machining process is interspersed throughout the entire process of the workpiece processing, each process needs to establish state requirements, such as the allowance of the machining allowance, the precision and tolerance of the positioning surface and hole, and the technical requirements of the orthopedic process. For heat treatment of blanks, various processes must be considered before and after.

4. Design of CNC machining process and processing route

The main task of CNC machining process design: determine the specific processing content, cutting amount, process equipment, positioning and installation methods and tool movement trajectory of the process, in order to prepare the program. Among them, the setting of the processing route is a very important link. The processing route is the movement path of the tool location relative to the workpiece during the cutting process of the tool. It not only includes the contents of the machining process, but also reflects the arrangement of the processing sequence. Therefore, the processing route is The important basis for the preparation of processing procedures.