When clamping the workpiece, WEDM must ensure that the cutting position of the workpiece is within the cutting range of the X-axis and Y-axis feed of the machine tool table, and also consider the motion space of the electrode wire. Try to choose common (or standard) parts, and the selected fixture should be easy to clamp and coordinate the dimensional relationship between the workpiece and the machine tool. When machining large dies, special attention should be paid to the positioning mode of the workpiece, especially at the end of machining, the deformation of the workpiece and the action of gravity will clamp the electrode wire and affect the machining.

1, cantilever clamping

The workpiece is clamped by cantilever, which is convenient and universal. However, due to the extension of one end of the workpiece, the verticality error between the cutting surface and the upper and lower planes of the workpiece is easy to occur. Only used in the case of low machining requirements or short cantilever.

2. Clamping at both ends

It is convenient, stable and high in positioning accuracy to clamp the workpiece by supporting at both ends, but it is not suitable for clamping larger parts.

3. Clamping of bridge support

This method is to clamp the workpiece after putting the shim on the universal fixture, which is convenient for clamping and can be used for large, medium and small workpieces.

4, plate support mode clamping

According to the shape and size of the common workpiece, the workpiece is clamped with a supporting plate with a through hole. This method has high clamping accuracy, but poor universality.

Adjustment of WEDM workpiece;

When the workpiece is clamped by the above method, it must be adjusted by the alignment method, so that the positioning datum plane of the workpiece is parallel to the feeding direction X and Y of the machine tool worktable and the worktable respectively, so as to ensure the relative position accuracy of the cutting surface and the datum plane. Commonly used alignment methods are:

1. Align with the dial indicator.

Fix the dial indicator on the wire frame or other positions with a magnetic dial indicator holder. The probe of the dial indicator contacts the base surface of the workpiece, move the workbench back and forth, and adjust the position of the workpiece according to the indicated value of the dial indicator until the deflection range of the dial indicator reaches the required value. Alignment should be carried out in three vertical directions.

2. Alignment marking method

When the mutual position accuracy between the cutting pattern of the workpiece and the positioning datum is not high, the scribing method can be used for alignment. Align the reference line drawn on the quasi-workpiece with the scriber fixed on the wire frame, move the workbench back and forth, visually observe the deviation between the scriber and the reference, and adjust the workpiece to the correct position.