The effect of high frequency and duty cycle in electrochemical microdrilling

Abstract

Pulse electrochemical micromachining possesses attractive features compared to conventional electrochemical machining processes based on a continuous current because it allows instantaneous electrochemical reaction by applying ultrashort voltage pulses. This study focuses on effects of applied frequency and duty cycle in electrochemical microdrilling on nickel plate. During microtool fabrication, tungsten micro-shafts are electrochemically etched to make two desired cylindrical microtools of different lengths and diameters to investigate the effects of pulsed frequency and duty cycle on electrochemical micromachining. The shape and size of the fabricated microholes, machining time, actual material removal rate (MRRact) and the number of short circuits are considered as response factors. Shapes of micro-drilled holes are measured and compared to tool geometry. As for both short and long microtools, MRRact and machining time respectively decreased and increased with an increase in applied frequency. But the MRRact and machining time respectively increased and decreases with an increase in duty cycles. Experimental data reveals that there is a strong correlation among the shape and size of the microhole fabricated with applied frequency and duty cycle during microdrilling. However, MRRact was found to be much higher for short tool than a long tool.