There are many different methods of mold processing. Let's analyze the knowledge about EDM processing methods. EDM is mainly used to etch off excess metal by generating an electrical corrosion phenomenon when a pulsed spark discharge is generated between the tool and the workpiece (positive and negative electrodes) to achieve the size, shape and surface quality specified by the technical requirements of the part.
1. The mold EDM processing method must meet three conditions:
1 It is necessary to maintain a certain gap between the tool electrode and the workpiece to be machined surface, so it is necessary to have automatic feeding and adjusting device of the tool electrode in the electric discharge machining;
2 spark discharge must be a transient pulse discharge, for which EDM must use a pulse power supply;
3 Spark discharge must be carried out in a liquid medium with a certain insulating property.
2. Factors affecting the erosion rate of EDM: electrical standard, polarity effect, thermal constant of metal material, working fluid, and chip evacuation conditions.
3. Factors affecting the accuracy of EDM: various errors of the machine tool itself, manufacturing accuracy of the tool electrode, positioning and mounting error of the workpiece and the electrode, size and consistency of the discharge gap, loss of the workpiece electrode and processing stability.
4. Electrode material requirements for EDM: low loss, stable processing, high productivity, good machinability and low price. Common materials: copper, graphite, cast iron, steel, brass, tungsten alloy, silver tungsten alloy. Structure: 1 integral electrode 2 inlaid electrode 3 combined electrode.
5, EDM forming cavity mold method: 1 single electrode translation method 2 multi-electrode replacement method 3 decomposition electrode method.