Electrical discharge machining

A spark erosion machine is an abrasive machine tool used to machine electrically conductive materials by means of spark erosion process.

The electric discharge machine needs a tool ( electrode) made of a good electrical conductor such as copper, tungsten, or graphite, and a dielectric that fills the space between the tool and workpiece for machining. During machining, a voltage between the workpiece to be machined and the electrode which is clamped into the machine, is applied. The electrode is a negative form of the shape to be introduced into the workpiece to be machined.

During the processing of an arc between the electrode and the workpiece is generated by pulsating direct current. In this case, components are removed from the workpiece by evaporation or by spalling. The removed or vaporized components are swept away by a nonconductive fluid, such as oils ( dielectric).

The problem with the method are the low ablation volume and the high manufacturing costs of the electrode, which may account for some cases more than 50 % of the total cost.

Application, see EDM machines, especially in tool making. They are used for processing of any metals and metal alloys used (even tempered), aluminum, copper, brass, and exotics such as molybdenum and zirconium, such as steel. Similarly, other conductive materials such as graphite and some types of ceramics can be processed very erosive. In the field of die-sinking EDM is often supplemented by HSC milling machines (for hard and hardened metals ) and 5 -axis milling machines or partially replaced.

Species

EDM machines are available in two versions which offer different processing options:

• Wire EDM ( electrical discharge cutting)
• Die sinking where there are different versions ( eg Drill EDM ) here who is mainly in the number and nature of their axes (X, Y, Z, C. ..) differ ( spark erosion sinks)