Machining of micro rotational parts by wire electrical discharge grinding

Micro rotational parts are used in several industrial sectors. Well-known applications are micro shafts of gears, ejector pins in forming tools, pin electrodes for micro electrical discharge drilling or micro stamping dies. Depending on the geometrical complexity of micro rotational parts different process variants of micro electrical discharge machining characterized by a rotating work piece can be used: wire electrical discharge grinding (WEDG) with fine wire electrodes, electrical discharge turning (EDT) with micro structured tool electrode, cylindrical electrical discharge grinding (CEDG) with micro profiled disk electrode. Characteristic to these process variants is the superimposed relative motion between the rotating electrodes and the feed. This relative motion can be varied in a wide circumferential velocity range to improve the material removal process. The paper gives an overview of kinematic and technological restrictions and requirements of the WEDG process influencing the process behavior with respect to the technological requirements of micromachining.