Experimental exploration and assessment of failure analysis on wire electrical discharge machining processing of Inconel 686 by integrated MOORA-PCA approach

Abstract

Inconel 686 superalloy is possessing on exceptional strength and corrosion resistance that well-suited in extreme operational circumstances of functional systems. These alloys excel under temperature fluctuations, mechanical stress, acidic conditions, and saltwater exposure, leading to their use in chemical processing, oil and gas, and aerospace industries. However, their hardness and low thermal conductivity pose challenges for conventional machining. Wire electrical discharge machining (WEDM) offers a nonconventional solution, enabling precise fabrication of intricate products. Optimizing WEDM process variables is essential for economical, high-quality machining. This study investigated the effects of peak current (IP), servo voltage (SV), pulse duration on (T_ON), pulse duration off (T_OFF), wire feed rate (WFR), and wire tension (WT) on WEDM performance. An orthogonal L27 array was used to design the experiments, and analysis of variance was applied to develop mathematical models for material removal rate (MRR), surface roughness (SR), and kerf width (KW). From the experimental trials the values of optimal process variables combination from Multi-Objective Optimization by Ratio Analysis-Principal Component Analysis IP: 11 A, SV: 25 V, T_ON: 122 µs, T_OFF: 44 µs, WT: 7 kg and WFR: 3 mm/min were determined. From result of observed outcome response of confirmatory test, the improved MRR at 25% (0.07904 to 0.09852 g/min), reduced SR and KW at 33% (2.945 to 1.967 µm) and 17% (0.100 to 0.083 mm) respectively. The SEM analysis revealed that adjusting process variables led to a more refined surface finish, minimizing the formation of large craters and bulges caused by excessive sparks and debris collisions during machining.