Comparison of EDM and laser trepanation micro-drilling processes using multiple-criteria decision analysis

In order to create cooling holes in gas turbines, laser and EDM micro-drilling processes are often relied upon due to the difficult-to-cut metals used in these components. Currently, there is no strategy for selecting the best manufacturing process for this application. The operating principles, relevant parameters, operational productivity, quality, and cost of manufacturing using laser and EDM methods differ significantly. The objective of this study is to compare laser trepanning and fast hole EDM-mediated micro-drilling in nickel superalloys (Inc718) using operational productivity, quality, and cost. For each process, a combination of input variables was generated using a central composite design statistical model. Material removal rate, dilation, roughness, and energy consumption were then utilized in a multiple-criteria decision analysis. These values were used to order the combinations of input variables for each of the micro-drilling processes analyzed. The CRITIC method and best-worst method were used to weight the criteria. The ordering methods used were TOPSIS, COPRAS, and PROMETHEE II. The results were aggregated using the average and the Borda method. The trepanning laser machining process delivered the best performance, with optimal settings of 0.4 ms pulse time, a trepanning speed of 70 mm/min, and 0.9 J of energy.