The characteristics of NC machining have put forward two basic requirements for fixture: one is to ensure that the coordinate direction of fixture is relative to the coordinate direction of machine tool, and the other is to coordinate the dimension relation between parts and machine tool coordinate system.
In addition, the following points are to be considered:
1, when the parts processing volume is small, should try to use combination fixture, adjustable fixture and other general fixture, in order to shorten the production preparation time, save production costs.
2, in batch production only consider the use of special fixture, and strive to simple structure.
3, the parts of the loading and unloading should be fast, convenient, reliable, to shorten the downtime of the machine tool.
4, the fixture on each part should not hinder the machine tool on the parts of the surface of the processing, that is, the fixture to open, its positioning, clamping mechanism components can not affect the processing of the knife (such as collision, etc.)