1. The basic principles of positioning and installation
When machining parts on a CNC machine tool, the basic principle of positioning and installation is to choose a reasonable positioning datum and clamping plan. Pay attention to the following points when choosing:
1. Strive for a unified benchmark for design, process and programming calculations.
2. Minimize the number of clamping times, and process all the surfaces to be processed after positioning and clamping once as much as possible.
3. Avoid the use of machine-occupied manual adjustment processing schemes to give full play to the effectiveness of CNC machine tools.
Second, the basic principles of choosing 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 size relationship between the parts and the machine coordinate system. In addition, the following points should be considered:
1. When the batch of parts is not large, modular fixtures, adjustable fixtures and other general fixtures should be used as much as possible to shorten production preparation time and save production costs.
2. Only consider the use of special fixtures during mass production, and strive to have a simple structure.
3. The loading and unloading of parts should be fast, convenient and reliable to shorten the machine stop time.
4. The parts on the fixture should not hinder the machining of the surface of the parts by the machine tool, that is, the fixture should be open, and its positioning and clamping mechanism components should not affect the knife during processing (such as collisions, etc.).
