Elektroerosion

Elektroerosion, also known as electrical discharge machining (EDM), is a non-traditional manufacturing process that removes material from a conductive workpiece through controlled electric discharges between an electrode and the workpiece in a dielectric fluid. There is no direct contact between tool and workpiece during machining; material is removed by localized melting and vaporization caused by spark energy, enabling the creation of complex shapes in hard materials.

The process has two main forms. Die-sinking EDM uses a shaped electrode to form cavities or complex cavities in the workpiece, while wire EDM employs a continuous, thin wire as the electrode to cut along a programmed path. In both variants, pulsed electrical energy ionizes the dielectric between the electrodes, generating sparks that erode small amounts of material. The dielectric fluid acts as an insulator, a spark medium, and a flushing agent that carries away debris. Servo systems maintain a controlled gap and trajectory. Micro-EDM variants enable very fine, near-microscale features.

Materials and applications. EDM is suitable for conductive materials, including hardened steels, carbide, and superalloys, which are difficult to machine by conventional means. It is widely used in tool and die making, mold fabrication, aerospace components, medical implants, and intricate cooling channels or cavities where precision and complex geometries are required. Advantages include the ability to machine hardened workpieces and produce sharp internal features, while limitations involve relatively slow material removal rates, the formation of a surface recast layer, electrode wear, and the need for effective dielectric handling and post-processing.