Multi-optimization of µ-EDMed Arrayed Microrods Using Gray Relational Analysis

Fabrications of arrayed microrods using microelectrical discharge machining (EDM) are widely employed for drilling of multiple as well as arrays of microholes. It is commonly used in various applications such as perforated shadow mask, semiconductor device, and microheat exchanger. In the present work, gray relational analysis (GRA) has been proposed to optimize the multi-response performance characteristics (i.e., machining time and tool wear rate) of the process. GRA methodology is applied to optimize fabrication process of arrayed microrods to obtain the better dimensional accuracy with minimum tool wear and machining time using reverse micro-EDM (R-µEDM) process, a variant of micro-EDM process. In micro-EDM, tool wear and machining time are directly influence the dimensional accuracy of the microrods. The dimensional accuracy can be improved by reducing the tool wear and machining time during the fabrication process. The experimental investigation considers voltage, capacitance, and feed rate as input parameters. GRA optimization result shows that voltage of 150 V; feed rate of 25 µm/s; and capacitance of 10,000 pF are found as the optimum process parameters. The capacitance contributes 26.07% being highly influenced, followed by voltage (24.20%) and feed rate (5.17%). Voltage and capacitance have the statistical significance of 95% confidence level on overall performance toward the response parameters for getting the better dimensional accuracy with minimum time duration.