Multi-objective optimization of roundness, cylindricity and areal surface roughness of Inconel 825 using TLBO method in wire electrical discharge turning (WEDT) process

Wire electrical discharge turning (WEDT) is a non-conventional machining process, which was developed to machine cylindrical components on difficult-to-machine, but electrically conductive materials with high precision. In the present work, roundness, cylindricity and areal surface roughness of the parts created by WEDT process are investigated. Inconel 825 was the material chosen for the present study. The main objective of this study is to identify the optimum process parameters required to obtain improved geometry of the turned components with respect to roundness, cylindricity and areal surface roughness. The effects of machining parameters in WEDT process on the output responses are studied using experiments based on Box–Behnken design. ANOVA has been performed to study the effect of process parameters on the output responses. A novel optimization approach is used to identify the optimum parameters for each response. Teaching learning-based optimization (TLBO) is used to optimize the process, considering the three output responses in order to improve the quality of the turned products. Validation experiments were conducted, and the predicted results were verified. It is observed that the roundness, cylindricity and areal surface roughness of components machined with WEDT process obtained from TLBO technique and validation experiments are in close agreement. The surface morphology of the samples having maximum and minimum Sa value was studied using SEM micrographs. Finally, a microelectrode of 185 µm diameter and 4 mm length was successfully fabricated with multiple cut strategy using the WEDT setup in order to demonstrate the process capability.