One kind of electrode in mold making is the discharge end of EDM, which is used to process the mold cavity, generally made into the required shape, and the material can be graphite and copper ; the other is the discharge end of wire cutting, and the material is molybedenum. Multi-electrode machining means that the section of the workpiece to be machined requires high precision, and the discharge part should be processed for several times, with the rough discharge of large flat movement at the beginning and the fine discharge of smaller flat movement in the end.
Electrode is the discharge end of EDM, metal material, pre-made shape, corrode the workpiece into the prescribed shape. Its working principle is to pass current on two electrodes(workpiece and copper electrode), filled with dielectric during the working period, when the two electrodes are close to each other, the dielectric in the middle is struck, forming a gap discharge, and the metal is corroded by the high temperature generated by the discharge, so as to get the required shape. The main parameters that have a strong influence on the EMD process are the pulse current and pulse frequency. Through the electrodes it is possible to process workpiece that cannot be processed by conventional cutting. The disadvantages is that the machining process needs a long time and non-conductive material cannot be machined.
Precautions before EDM machining
1. Select the suitable material
In the cavity processing, graphite is the commonly used electrode material, you can choose the special graphite with high strength and high density for electrode processing. Meanwhile, the purple copper electrode is also a common material for electrode making. When using purple copper as the electrode material, you need to pay attention to the purify of purple copper.
2. Dimensions
Making electrodes is the first step of EDM, and the electrodes are machined according to the detailed drawings. The tolerance for electrode processing is ±0.01mm.
3. Electrode fixing
The purpose of fixing the electrode is to prevent the electrode from loosening during the EDM process, thereby to avoid processing errors.
4. Discharge gap controlling
EDM is the key part for controlling the cavity size, and the electrode, as an important tool for EDM, needs to be processed in strict accordance with the drawings.