Edm is mainly to use the electric corrosion phenomenon of the pulsed spark discharge between the tool and the workpiece to remove the excess metal, so as to achieve the size, shape and surface quality stipulated by the technical requirements of the parts.

1. The die edm machining method must meet three conditions:

(1) must make the tool electrode and the workpiece is processed between the surface to maintain a certain gap, so in the edm must have tool electrode automatic feed and adjustment device;

(2) spark discharge must be instantaneous pulse discharge, so the edm must use pulse power supply;

(3) spark discharge must be in a certain insulation performance of the liquid medium.

2. Factors affecting the erosion rate of edm forming: electrical gauge, polarity effect, thermal constants of metal materials, working fluid, chip removal conditions.

3, the factors that affect edm machining accuracy: various errors of the machine tool itself, tool electrode manufacturing accuracy, workpiece and electrode positioning and installation errors, discharge gap size and consistency, workpiece electrode loss and processing stability.

4, edm electrode material requirements: small loss, stable process, high productivity, good mechanical processing performance, low price.Common materials: copper, graphite, cast iron, steel, brass, tungsten alloy, silver tungsten alloy.Structure: (1) integral electrode (2) Mosaic electrode (3) combination electrode.

5, electric spark forming processing cavity die method: (1) single electrode translation method (2) multi-electrode replacement method (3) decomposition of the electrode method.