Modelling, simulation and experimental investigation for generating ‘I’ shaped contour on Inconel 825 using electro chemical machining

Abstract

Performance in electrochemical machining (ECM) is primarily governed by flow characteristics of electrolyte. Although, some analytical work has been reported on mechanism of material removal and distribution of current density, information on flow characteristics of ECM, pressure and temperature profile is relatively scarce. In the present work, analytical simulation of various phenomena occurring in the IEG such as velocity variation, pressure variation, turbulent kinetic energy and temperature profile to study passivation was performed using a ‘I’ shaped tool and Inconel 825, a nickel-based super alloy as workpiece material. According to computational fluid dynamics (CFD) simulation results, velocity distribution is minimum while the turbulence is maximum near the bend and sharp corners. Simulation also indicated formation of negative pressure zone around the periphery of the tool resulting in eddies. Temperature was found to be less around the central region of electrolyte in machining gap as well as near the sharp corners due to high flow velocity and turbulence respectively. Further, experiment was conducted to correlate the finding of simulation with various performance measures in ECM such as material removal rate (MRR), surface roughness and overcut. Effect of parameters like voltage, concentration and feed rate was investigated and finally optimised using grey relation analysis which yielded concentration of 80g/l, feed rate of 0.2mm/min and voltage of 10V for the best responses.