Processing of Triangular Profile on Inconel-825 Superalloy by Wire Electrical Discharge Machining and Corner Error Optimization Using Teaching Learning-Based Optimization Technique

Sharp corners without error are extremely difficult to achieve in the wire electrical discharge machining (WEDM) process, which is critical for precision machining. The current study looked at how WEDM parameters such as spark on time, spark off time, peak current, and cutting angle affected corner error during curved profile cutting for Inconel-825 superalloy. In this work, an attempt has been made to optimize the corner error during curved profile (triangular) cutting on Inconel-825 superalloy by WEDM. The corner error was optimized using the Teaching Learning-Based Optimization (TLBO) technique. Furthermore, surface integrity analysis of machined surface at optimized parameters in terms of surface morphology, phase analysis, and recast layer formation was performed. On increasing cutting angle and spark off time, decrease in corer error was noticed, whereas corner error increases with on increasing spark on time and peak current. Cutting angle and spark off time were found the most influencing factors followed by peak current and spark on time. At spark on time 32 mu s, spark off time 17 mu s, peak current 1 A, and cutting angle 60o, a smaller corner error of 0.0525 mm(2) was achieved. Trim cutting resulted in a significant reduction in corner error by 42 and 19%, respectively, in the first and second trim cuts. SEM micrograph of machined surface shows the presence of globules, craters, lumps of debris, and micro-voids. A thin recast layer of thickness 30 mu m was observed during investigation of cross-sectional SEM image of machined surface. Fe3Co, Fe3Ni, Co0.115Fe0.885, Co0.06Fe0.94, Al0.29Ni0.27Ti0.44, and Fe1.2Ni0.8 compounds were noticed during XRD analysis of machined surface.