Performance analysis of closed-loop electrochemical discharge machining (CLECDM) during micro-drilling and response surface methodology based multi-response parametric optimisation

Abstract

ABSTRACT In electrochemical discharge machining (ECDM), sustaining the effective machining gap during micro-drilling is strenuous because of the tool contact with the material. It deteriorates the geometrical features and causes high tool wear. Closed-loop ECDM (CLECDM) works on the adaptive tool feed that retracts the tool upon its contact with the material. Thermal cracks and hole cylindricity of the micro-hole is improved alongside the improvement of 15.9% in material removal rate (MRR) and 14.8 % in tool wear rate (TWR). A study on the number of tool contacts (NTC) is performed concerning distinctive parameters since it influences both MRR and TWR. Moreover, the response surface methodology (RSM) based mathematical models are established to correlate the relationship between the parameters and to obtain multi-response optimisation. Applied voltage, electrolyte concentration, tool feed rate, and inter-electrode gap (IEG) are chosen as input parameters while MRR, TWR, and NTC are chosen as response parameters. The model’s adequacy is checked through analysis of variance (ANOVA) and found significant. The multi-response optimisation is acquired using desirability function (D = 0.7574) for maximising MRR and minimising both TWR and NTC. The obtained parameters are applied voltage: 50 V, concentration: 25 wt.%, tool feed rate: 4 mm/min, and IEG: 42.35 mm.