Process force analysis on sinking-EDM electrodes for the precision manufacturing

Electro Discharge Machining is no longer taken as a “force free” process. Studies are being completed in order to understand how these forces are being exerted on the electrodes and how they might affect the processing of highly precise or high aspect ratio geometries. This paper studies process forces on macro Sinking-EDM with the use of two highly precise piezoelectric axial force sensors which measure single discharge forces simultaneously at the tool and workpiece sides. At the same time, the vibration amplitude and frequency of tool electrodes are measured, along with the analysis of high-speed-camera photographs showing a chronological sequence of gas bubble formation in terms of their dilatation and collapse, allowing a more detailed view into the process. The understanding of the dynamic trends of these process forces allows drawing conclusions about the generation of the pressure field along the working gap and its influence on tool electrode vibration which can decrease the final desired precision of the manufactured workpiece.