Finite Element Modeling for Comparing the Machining Performance of Different Electrolytes in ECDM

Abstract

Electrochemical discharge machining (ECDM) is a triumphant process for producing micro-holes in glass materials and yet holds the potential for improvement. In ECDM, electrolyte selection is crucial as it controls the spark pattern and flushes debris from the machining zone. Despite numerous experimental studies, few analytical studies were reported for ECDM modeling and finite element modeling-based electrolyte’s comparative study is not reported yet. This study focuses on developing a thermal model to compare the ECDM performance in terms of material removal rate (MRR) for different electrolytes, viz. NaOH, KOH, and NaCl. The plots of temperature distributions are obtained underneath the spark and further processed to evaluate the MRR. Predicted results are observed to be in accordance with the experimental results. The effects of electrolyte concentration, applied voltage, spark radius, and duty ratio on MRR are analyzed through simulations. Results show that MRR decreases with the increase in spark radius while increases with the increase in other parameters. NaOH electrolyte produces higher MRR; an increase of 8.72 mg and 10.18 mg is observed when compared to KOH and NaCl at 60 wt% concentration. Moreover, experimental studies are performed to evaluate the electrolyte’s effect (includes NaNO3) on radial overcut (ROC) and hole circularity. KOH electrolyte provides the least overcut and better hole circularity due to stable and smooth spark pattern. An improvement of 32.1% in overcut and 40.8% in hole circularity was observed using the KOH when compared to NaNO3. NaOH and KOH are revealed as the successful electrolytes for machining with ECDM.