Parametric Optimization of EN-31 Steel Using Electric Discharge Machining

Abstract

This investigative study was conducted for the parametric optimization of EN-31 material by using a non-conventional machining known as Electric discharge machining (EDM). EN-31 is a steel alloy that is generally used in aerospace industry, automotive parts manufacturing, die making etc. because it possesses high degree of rigidity with extremely good compressive strength and resistance to abrasion. The primary objective of this study was to analyze the impact of four input factors i.e. pulse on time (Ton), pulse off time (Toff), current (LV), voltage (HV) on the five output responses i.e. machining time (Tm), MRR, EWR, Ra and base radius (R). In this study design of experiment (DOE) approach with full factorial design was systematically conducted. Basic experimental runs were prepared and performed and after that data was analyzed using ANOVA to identify significant input factors that has most impact on each output response that are mentioned above. After identification of significant factors optimized input factors and output responses were calculated using ANOVA. The results showed that for machining time (Tm), LV and Ton were significant factors with optimized values of 50 A and 6.5 µs, respectively, resulting in a Tm of 654.29 seconds. For material removal rate (MRR), Ton was the significant factor with an optimized value of 6.5 µs, achieving a maximum MRR of 0.0157 g/min. For electrode wear rate (EWR), LV and Ton were significant with optimized values of 30 A and 4 µs, respectively, resulting in a minimum EWR of 0.07 g/min. Ra optimization revealed that the combination of HV, LV, Ton and Toff were significant, with optimized settings of 50 A, 0.7 V, 4.0 µs and 6.5 µs, respectively, yielding a minimum Ra of 0.018 mm. For base radius (R), the significant factors were HV, LV, Ton and Toff, with optimized values of 0.6152 V, 50 A, 6.5 µs and 6.5 µs, respectively, resulting in a base radius of 1.5 mm. This parametric optimization is extremely significant because EN-31 is a material used in critical applications requiring high strength, hardness and abrasion resistance such as automobile engine components, aerospace rocket parts and dies subjected to extreme temperatures and pressures throughout their lifecycle. Optimizing EDM parameters facilitates the use of this non-conventional machining process for manufacturing EN-31 parts thus enabling researchers, manufacturers, designers and industry practitioners to achieve higher productivity, excellent surface finishes and lower manufacturing costs as compared to traditional manufacturing techniques. This optimization allows for more efficient and effective production of high-performance parts thus making it an invaluable advancement in various industrial sectors.