Investigation on the migration of material from tool to workpiece in micro-EDM drilling

Electrical Discharge Machining (EDM) is a process used to remove material by means of electrical discharges between the tool electrode and the workpiece. During the process, particles of the electrode migrates to the workpiece and vice versa, causing contamination. This can result in modifications of the physical and mechanical properties of the workpiece surface. Aim of this work is to study the migration of material from the tool to the workpiece during the execution of micro holes using micro-EDM. Micro holes were executed on stainless steel and titanium sheets; tubular electrodes made of brass and tungsten carbide were used while peak current and voltage were varied. The surfaces were analysed quantitatively using energy-dispersive x-ray (EDX) for detecting the surface composition. The migration of material was observed. Peak current and voltage resulted to affect in non–homogeneous way the morphology and the distribution of the elements on the hole surface.