%0 Journal Article %A Pellerin, N. %A Pellerin, Stephane %A Bratasz, L. %A Musiol, K. %A Dzierzega, K. %A Miernikiewicz, A. %A Chapelle, J. %D 2001 %I Begell House %N 3 %P 15 %R 10.1615/HighTempMatProc.v5.i3.140 %T ANALYSIS OF SOME ELECTRICAL DISCHARGE MACHINING MECHANISMS %U https://www.dl.begellhouse.com/journals/57d172397126f956,3f6e18f522979e73,5551432a762cfff2.html %V 5 %X Electric Discharge Machining (EDM) is a process in which an electric discharge in a dielectric liquid involves electrodes erosion of the device. Generally, erosion of one of the electrodes is faster than for the other. A current impulse generates an electric discharge that evolves of a spark toward an arc discharge, provided that the length of the current impulse is sufficiently long. The constituting material of treated electrodes is present in the created plasma, as attests apparition of emitted spectral lines.
In the EDM process, the copper anode is not eroded. In contrary, the steel cathode can be eroded when the current impulse is sufficiently high. To have a better understanding of processes caused by EDM plasmas which play a role in erosion, including the physical and chemical transformations in electrodes, it is important to analyse the materials issued of erosion: i.e. ejected particles and electrodes after treatment. Their observation and study by techniques usual in material science has been undertaken. Composition studies have shown enrichment with carbon for the steel ejected residual particles and cathode surface, on a depth of around 20 mm. The electrode surface suffers also a morphological evolution with cavities formation. Chemical analysis of residual particles shows chromium vaporisation during the EDM process. The liquid metal surface tension could be modified by migration of carbon and chromium what may be important in erosion efficiency. %8 2001-09-01