Spark erosion, which is sometimes referred to as Electric discharge machining or spark machining is a process for manufacturing the shape of object or a ‘workpiece’. An electrical current is discharged between two electrodes which are in the presence of a dielectric liquid, this produces a spark. It is the repeated action of this discharge which causes the removal of material from the workpiece and shapes the object in the desired fashion.
The two electrodes are referred to as the ‘tool’ and the other the ‘workpiece-electrode’. The intensity of the electric field is in inversely related to the distance between the two electrodes, thus the closer the electrodes are the more intense the field will become. When the electrodes are in close proximity the electric field will become larger than the strength of the dielectric and a flow of current will pass between the two electrodes
Once the workpiece has been shaped and the flow of current is ceased a new dielectric liquid employed in to the area between the electrodes. This will allow for the removal of debris that can accumulate around both electrodes. This removal of old dielectric solution and the inclusion of new dielectric liquid is referred to ‘flushing’. With the insulation properties of the dielectric restored the system is available for further spark erosion.