In CNC machining center and CNC milling machine, the use of fixture must adapt to CNC machining center machine tool precision, high efficiency, many aspects of simultaneous processing, program control and small batch production of a single piece.So in the design, selection of CNC machining center fixture, according to the characteristics of CNC machining center processing, need to pay attention to the following points:
Position requirements：the function of the fixture is not only to clamp the workpiece, but also to accurately determine the workpiece and the mutual position between the machine tool, cutting tool, the workpiece position precision is guaranteed by the fixture, not affected by the worker's technical level.And each positioning surface on the furniture or workpiece programming zero reference.Nc machine tool in processing when two or more parts of the same shape, in a process of each parts position relative to the position of the machine zero point should be fixed, machining parts, per piece tool trajectory and the corresponding position in the machine tool coordinate system is fixed, so the after each clamping parts location should be the same.If the fixture cannot guarantee the precise positioning of the parts on the CNC machining center machine tool, then each time the clamping parts, the relative position of the workpiece coordinate system dot and the positioning reference of the parts will change, will affect the processing quality of the parts.
In addition, the positioning of the fixture should be reliable, the positioning element should have a higher positioning accuracy, the positioning position should be easy to clear debris, no slant deposition.If the positioning area of the workpiece is too small, the process boss or auxiliary datum can be considered.
No interference:after the workpiece is clamped on the furniture, all parts of the generation of processing should be exposed, and some components on the fixture such as the pressing plate, screw, clamp specific, etc., can not interfere with the tool.
Jig disassembly, use and the workpiece loading and unloading should be convenient and fast.
The rigidity and stability of the fixture should be good, and the structure of the fixture should be simple.
The clamping deformation must be considered when the fixture is designed.