The selection and use of fixtures for CNC milling machine machining centers mainly include the following aspects: According to the characteristics of machining centers and precision machining needs, currently commonly used fixture types include special fixtures, modular fixtures, adjustable fixtures, group fixtures, and workpieces. The same reference positioning and clamping system. Various factors should be considered comprehensively when choosing, and a more economical and reasonable fixture form should be selected. The order of selection of fixtures is generally: general fixtures are used in single-room production; modular fixtures should be given priority in mass production, adjustable fixtures should be considered second, modular fixtures and special fixtures should be considered again; when the clamping accuracy is very high, workpieces can be configured The unified standard is defined as the clamping system.

The high flexibility of the machining center requires that the fixture is more compact and simple than the ordinary machine tool mechanism, and the clamping action is faster and more accurate. Minimize the auxiliary time, make the operation more convenient, successful, safe and ensure sufficient rigidity and flexibility. Therefore, pneumatic and hydraulic clamping devices are often used. In order to keep the workpiece fully exposed to all the surfaces to be processed in this positioning and clamping, the fixture should be as open as possible, and the spatial position of the clamping element can be as low as possible. It is necessary to leave room for the tool movement trajectory. The fixture cannot interfere with the tool path of each step. When there is no suitable clamping position outside the box, the internal space can be used to arrange the clamping device.

Considering the distance between the spindle of the machine tool and the worktable and the clamping length of the props, the installation position of the fixture on the worktable of the machine tool should ensure that the workpiece processing content can be completed within the range of the spindle stroke. In the process of precision machining, in order to satisfy the processing of front, rear, left, and right workpieces, the positioning accuracy of the workpiece is mainly maintained, and the requirements are indicated in the process documents when necessary.