Quality Enhancement with Ultrasonic Wave and Pulsed Current in Electrochemical Machining

This paper presents the results of enhancement in Electrochemical Machining (ECM) by combining pulsed current and ultrasonic wave in flowing electrolyte through an electrode. Teflon coated stainless steel tubes were used as electrodes to produce deep holes in 6061-T6 aluminum. Material removal rate and hole quality were measured on a 3D optical profiler to study the effect of pulsed current amplitudes, pulsed frequencies, machining times, and ultrasonic wave amplitudes. Although pulsed current improves the removal rate, cavitation induced microjet suppresses the ionization process. The shockwaves from busting of cavitated bubbles break the aluminium tribromide by-product into fine powder that flows and polishes the workpiece surface. Although ultrasonic wave at 40 kHz compromised material removal rate, it significantly enhances the part quality by reducing surface roughness from 2.5 μm to 1 μm. The combined effect of pulsed current and ultrasonic wave reduces taper angle of ECM'ed holes sidewall from ∼11° to 1°.