Performance investigation of variant polymer graphite electrodes used in electrochemical micromachining of ASTM A240 grade 304

Abstract

ABSTRACTIn this paper, experiments in Electrochemical Micromachining (ECMM) were conducted to produce micro-holes of high aspect ratio using a cathode ‘Polymer Graphite Electrode’ (PGE). The effect of electrochemical dissolution of ASTM A240 type 304 stainless steel is comparatively studied using cryogenically treated PGE (CTPGE) tool and non-treated PGE tool (NTPGE) that owes to enhance the overall quality of micro-hole produced, which is assessed on the basis of the most imperative output responses namely the material removal rate (MRR), and the Overcut (Oc) in relation to the predominant input process parameters namely, Voltage (S1), Electrolytic concentration (S2) and the Duty cycle (S3). Response surface modeling based on Box-Behnken (BB) DoE was used to obtain the corresponding responses for the process factors. Numerical models were developed to study and effects of process factors individually and their interactional effect. ANOVA was used to study the statistical significant process factors. The outcome of the multi-objective optimization based on cuckoo search algorithm (MOCS) was found to be enhanced, owing to better surface characteristics of the workpiece machined using the CTPGE tool. The effect of the micro spark and stray current have dwindled when using CTPGE electrode that can be visually seen via SEM.