Machining performance, economic and environmental analyses and multi-criteria optimization of electric discharge machining for SS310 alloy

Abstract

With the expansion of the manufacturing sector, it has become crucial to incorporate sustainable production methods in order to remain competitive in the market. This study focuses on addressing the needs of the manufacturing industry by conducting a sustainability analysis of electric discharge machining for SS310 alloy. The analysis explores the impact of various electrode materials, for instance, copper and brass, as well as different machining variables, including discharge current (I = 4–12 A), spark gap (SG = 6–12 mu), pulse duration (Pon = 15–45 μs), and duty cycle (DC = 75–85%) using Taguchi method. The objective is to optimize the machining performance measures, which includes material removal rate (MRR), surface roughness (Ra), electrode wear (EW), and energy consumption (EC). In addition, the economic analysis of the machining process takes into account factors such as energy cost, dielectric consumption cost, EW cost, labor cost, and machine depreciation cost for both types of electrodes. Furthermore, the study investigates the carbon emissions resulting from EC, dielectric consumption, and EW to assess the environmental impact of the machining process. Multi-criteria decision-making approach is employed to assess the sustainability of the machining process by taking into account several performance, cost and environmental factors simultaneously. From empirical analysis, it has been observed that the copper electrode outperformed the brass electrode in terms of MRR (2.67 mm³/min), Ra (3.36 µm), EW (0.272 g), and EC (145.08 kJ) due to its superior electrical and thermal characteristics. In the cost analysis, copper offered lower costs for EC (2.02 PKR) attributed to its higher electrical conductivity while higher costs in terms of EW (5.5 PKR) and dielectric consumption (5.2 PKR) than brass. However, the analysis of labor and machine depreciation costs revealed that the application of copper electrode results in lower costs (80.1 and 99.3 PKR, respectively) than the brass electrode primarily due to its shorter machining time. The analysis of the environmental impact showed that the utilization of a copper electrode leads to reduced carbon emissions of 9.8 g CO₂ due to its lower EC during the machining process. However, the copper electrode results in higher emissions from EW (5.07 g CO₂) and dielectric consumption (54.58 g CO₂) compared to the brass electrode. Based on the multi-criteria decision-making using the composite desirability function approach, it is evident that the copper electrode exhibits superior performance in terms of MRR, Ra, and total machining cost. Conversely, the brass electrode demonstrates better performance in terms of overall carbon emissions.