On electrochemical machining with an interelectrode slit for a partially insulating cathode

Electrochemical machining is an established non-conventional machining process in which material removal during electrolysis relies on the quantity of electricity passed through the electrolyte. The amount of electricity passed further depends on several factors, such as electrochemical reactivity/dissolution, penetration rate, tool properties (profile, surface area, and material), electrical conductivity, chemical composition, temperature sensitivity, crystal structure, and initial surface roughness (Ra) of workpiece material, voltage, feed rate, electrolyte selection/concentration, etc. As per reported studies, a thermoplastic inter-electrode slit of rectangular/square profile between the tool and workpiece in modified electrochemical machining helps to generate the cavity with a better aspect (h/d) ratio without changing the tool profile. However, little has been reported on the effect of variation in interelectrode slit thickness on material removal rate/penetration rate. In this study, the results of experimental investigations for material removal rate/penetration rate with modified electrochemical machining using a square inter-electrode slit of variable thickness between the cathode (circular tool) and anode (workpiece) with 03 different materials (Al, Cu, and Ti) have been presented. Taguchi L18, orthogonal array-based design of experiments, has been used in parametric optimization of the modified electrochemical machining process. Overall, the best settings for material removal rate in modified electrochemical machining are electrolyte concentration 150 g/L, voltage 21 V, tool material Cu, workpiece Al, interelectrode slit thickness 1.5 mm, and tool feed rate 132 µm/min. The outcomes have been braced by scanning electron microscopy, energy dispersive spectroscopy, and Ra analysis.