First, the basic principles of positioning and installation
When machining parts on CNC machines, the basic principle of positioning and installation is to rationally select the positioning reference and clamping scheme. Pay attention to the following points when choosing:
1. Strive to unify the benchmarks of design, process and programming calculations.
2. Minimize the number of clamping operations, and process all the surfaces to be processed after one positioning and clamping as much as possible.
3. Avoid using the manual adjustment processing scheme to make full use of the performance of CNC machine tools.
Second, the basic principle of selecting fixtures
The characteristics of CNC machining put forward two basic requirements for the fixture: one is to ensure that the coordinate direction of the fixture is relatively fixed with the coordinate direction of the machine tool; the other is to coordinate the dimensional relationship between the part and the machine coordinate system. In addition to this, consider the following points:
1. When the part processing batch is not large, the combination fixture, adjustable fixture and other common fixtures should be used as much as possible to shorten the production preparation time and save production costs.
2. Only consider the use of special fixtures in batch production, and strive to make the structure simple.
3. The loading and unloading of parts should be fast, convenient and reliable to shorten the pause time of the machine.
4. The components on the fixture shall not interfere with the machining of the surface of the part by the machine tool, that is, the fixture shall be open, and the positioning and clamping mechanism components shall not affect the machining in the machining (such as collision).
