Anodic Polarization Study of Step Pulse Waveform for Machining Accuracy in Electrochemical Micromachining

Abstract

Electrochemical micromachining (EMM) shows promise as a versatile process for machining chemically resistant metallic materials in microsystems applications. A traditional rectangular pulse pattern has been modified into a step pulse waveform with a series of short rectangular pulses with different amplitudes. By establishing the experimental setup, anodic polarization behavior has been investigated throughout the dissolution process with 0.1M H2SO4 electrolyte solution at different applied voltages under the application of rectangular and step pulse waveforms. Utilizing the step pulse waveform, oscillation of the anode potential and transpassive state have been obtained during machining. Thus, from polarization studies, it has been observed that at 13 V, the current density is accelerated in a moderate range, i.e., 0 to 33A/cm2, which can reduce the anodic dissolution rate during the active state. Alternatively, the stray current effects and micro-sparks can be controlled because the duration of the passive state is very small and the RMS voltage can be reduced by 20.65% as compared to the rectangular pulse waveform. Further, overcut and tapering effects have been reduced by 83.99% to 51.39% and by 98.66% to 44.48% at the applied voltage of 13 to 17 V, respectively.