The rapid fixture is designed according to the mechanical principle of the double rocker mechanism in the planar four bar mechanism, and its basic structure is composed of the connecting rod, the frame and the two connecting rods and other four components.
When the two connecting points of the connecting rod and the connecting rod are connected with the articulated point of the connecting rod and the frame, when the three points are in a straight line, the mechanism is at the dead center position. At this time, the workpiece is pressed, no matter how much reaction (in addition to destructive reaction), also can not make the pressure head release, this is the mechanical principle of the dead center clamping.
In order to avoid in use, due to the impact of external force, the load change and the mechanical vibration design, the middle hinge point, slightly inner side to the other two hinge joints, in order to ensure maximum clamping force, always keep the fixture locked in stable state without loosening. Clamping force refers to the fixture in the locked position, does not produce mechanical deformation of the case, the pressure head of the workpiece maximum clamping force, the compression force generated in the pressure head in the arm to the nearest distance from the installation seat. The pressure of the pressure head is not constant, it changes with the pressure head on the different position of the arm, when the distance is far from the installation seat, the clamping force is reduced.
Now introduce the characteristics of the mold electrode: EDM graphite electrode, also known as copper.
The increasing complexity of the mold geometry and the diversification of the application of the product lead to the increasing demand for the discharge accuracy of the spark machine. Graphite electrode has the advantages of easy processing, high removal rate of electric discharge machining, small graphite loss, therefore, EROWA fixture is the most suitable, and some group based spark machine customers to abandon the copper electrode and the use of graphite electrodes. In addition, some of the special shape of the electrode can not use copper production, but graphite are more easily formed, and the copper electrode is heavy, not suitable for processing large electrode, these factors have caused some qunji spark machine application of graphite electrode.
As for the processing of the mould electrode, the first condition of the precision is the most important one. For the processing complexity of the graphite electrode, the most suitable fixture is the EROWA fixture.