Fabrication of deep-narrow microgrooves by micro-EDM using rotary dentate disc foil electrodes in emulsion

Abstract

To accelerate the renewal of working fluid in machining gaps, this paper proposed using a dentate disc foil electrode (DDFE) for rotary micro electrical discharge machining (micro-EDM) to fabricate deep-narrow microgrooves. The DDFEs were machined from 30 µm thick Fe78Si9B13 amorphous alloy foils through wire electrical discharge machining. Under different process parameters, a series of experiments for fabricating microgrooves were performed by micro-EDM using the DDFE in emulsion. The effects of applied voltage, machining modes, clockwise rotation speed of the DDFE, and machining depth on the microgroove width were investigated in detail. Furthermore, the morphologies and dimensions of the microgrooves were characterized using a laser scanning confocal microscope and scanning electron microscope. The experimental results indicate that when the applied voltage U was 60 V, the DDFE clockwise rotation speed n was 3000 r min−1, the machining depth H was equal to the tooth height of 500 µm, the supply direction of the working fluid was right yet opposite to the the workpiece feed direction, a stable and fast micro-EDM process was achieved and a deep-narrow microgroove of width approximately 78 µm and aspect ratio 6.4 was obtained. With the optimized process parameters, array microgroove structures and column microstructures were fabricated successfully on #304 stainless steel workpieces.