Optimization of machining characteristics for EDM of different nickel-based alloys by embodying of fuzzy, grey relational and Taguchi technique

摘要

Purpose- In the current exploration, the machinability of three different nickel-based super-alloy materials (Inconel 625, Inconel 718 and Nimonic 90) was experimentally investigated by using a die-sinking electrical discharge machining (EDM). The effect of changing important input process parameters such as pulse on time (T_(on)), off time (T_(off)), peak current (Ip) and tool rotation (TR) was investigated to get optimum machining characteristics such as material removal rate, roughness, electrode wear rate and overcut. Design/methodology/approach - Experimentation has been performed by using Taguchi L9 orthogonal design. An integrated route of fuzzy and grey relational analysis approach with Taguchi's philosophy has been intended for the simultaneous optimization of machining output parameters. Findings - The most approbatory factors for machining setting have been attained as: (T_(on) = 100 μs, T_(off) = 25 μs, Ip = 14 A, TR = 725 rpm) for machining of Inconel 625 and Inconel 718; and (T_(on) = 100 μs, T_(off) = 75 μs, Ip = 14 A, TR = 925 rpm) for machining of the Nimonic 90 material. Peak current has been observed as an overall influencing factor to achieve better machining process. Microstructural study through SEM has also been carried out to figure out the surface morphology for the EDMed Ni-based super alloys. Originality/value - The proposed machining variables and methodology has never been presented for Nimonic 90 alloy on die-sinking EDM.