Carl Hirschmann Academy – Principles of Spark Erosion

Spark erosion (EDM – Electrical Discharge Machining) is a modern, thermal erosive machining process for all electrically conductive materials (steel, aluminum, copper, brass, hard metals, conductive ceramics). In result of short voltage pulses, in a non-conductive medium (dielectric fluid) there are generated electrical discharges (flashover) coming quickly after another between electrode/wire and workpiece. These discharges heat the workpiece at the point with the smallest distance between electrode/workpiece so much that small areas of material are melted and removed. Depending on current and material property during this process deep craters can arise in workpiece.

It is distinguished between wire and sinking EDM. The, so called “bore eroding” or “EDM turning” can be reduced to the above mentioned two methods.

Main Application Fields of Spark Erosion

The main application fields for spark erosive sinking are manufacturing of injection molds, die casting molds, forging dies and prototypes where spark erosive cutting is used for manufacturing of cutting and stamping tools, profile dies etc.

Combined with a rotary indexing table or a rotating spindle the EDM technology offers a multitude of new and unimagined possibilities for manufacturing of complex and filigree shapes and structures, and all in highest precision and surface quality.

But how does this work? Unfortunately, the important processes in spark EDM are invisible. OELHELD offers a download brochure where important facts about sinking EDM are presented and explained in a comprehensible manner. These important facts are valid also for wire EDM where instead of the electrode a continuous wire is used.
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