Eco-Friendly Vibration-Assisted Electrochemical Polishing of Surfaces Generated by Wire Electrical Discharge Machining

Abstract The study demonstrates an in-house developed eco-friendly vibration-assisted electrochemical polishing (ECP) process, where the electrolyte flushing with the squeezing action of the vibrating tool eliminates the electrolytic by-products in the inter-electrode gap (IEG). A two-dimensional numerical model is developed to study the squeezing effect on changing bubble faction, anodic dissolution, and current density distribution. The effect of process parameters such as current density, electrolyte flow velocity, IEG, vibration amplitude of the tool, and vibration speed is analysed based on the experimental design matrix of response surface methodology (RSM) for minimising average surface roughness (Ra) of SS 304 component fabricated by electrical discharge machining. The numerical results indicated an increased flow velocity at IEG due to the vibration, resulting in an effective flushing of generated gasses. Current, IEG, vibration speed of the tool, vibration amplitude, and interaction between current-IEG, current-vibration speed, and IEG-vibration speed are identified as the most influential parameters by implementing the analysis of variance. The parameters are optimised using RSM, leading to a 96.71 % reduction in Ra value and a 62.54 % lower Ra value than the ECP without vibration, indicating the effectiveness of vibration-assisted ECP to achieve a high surface finish using eco-friendly electrolytes.