Heat Transfer and Marangoni Effect in the Electron Discharge Machining (EDM) Process

Witz, G., Revaz, B., Flükiger, R.
Université de Genève, Gap-Supra 20, Genève, Suisse

The parameters describing the heat transfer between the plasma channel and the workpiece during the electron discharge machining (EDM) process are still poorly understood. Models describing this phenomenon have many lacunas and can not be used for relevant predictions.

Using high resolution local temperature measurements and inverse calculations made with FEMLAB and MATLAB, we successfully developed a new model of the discharge sample interaction. On the basis of this thermal model, we calculated for the first time the fluid flow in the melt pool created by a discharge.

For semi-finishing pulsed discharges (5A, 100µs), the surface tension driven convection (Marangoni effect) was found to be significant and may therefore be the cause of the surface reconstruction and matter removal.