Evaluation of response characteristics using sensitivity analysis and TLBO technique of powder mixed wire EDM of Ti6Al4V alloy

Abstract

The development of Powder Mixed Wire Electric Discharge Machining (PMWEDM) aims to enhance both precise dimension and surface quality, making it a more efficient method for the cost-effective production of precise dies and tools compared to conventional Wire Electric Discharge Machining (WEDM. This approach effectively eliminates the need for secondary operations. The present study is focused on the parametric influence of surfactant with powder mixed WEDM process parameters during die corner cutting on Ti6Al4V material in the presence of surfactant and powder with dielectric. A sensitivity analysis was conducted to determine the significant influence of machining parameters and powder properties in conjunction with the dielectric. To empirically explore these variables, a central composite full factorial design based on response surface methodology was utilized. The design involved varying the pulse on-time (Ton) within the range of 30–90 µs, pulse off-time (Toff) within 3–11 µs, gap voltage (GV) within 40–80 V, and powder concentration (PC) within 2–10 g/L. The mathematical model was developed to predict the responses such as corner inaccuracy (CI) and surface roughness (SR) using RSM. The results conclude that the sensitiveness of powder concentration is highest. Apart from this, positive sensitiveness towards surface roughness is determined for three inputs: pulse on time, pulse off time, and powder concentration. In comparison, powder concentration shows positive sensitiveness towards corner inaccuracy. An artificial intelligence technique namely, Teaching learning-based optimization (TLBO) algorithm has been used to determine the best output. The minimum output for both responses, i.e. corner inaccuracy of 12982.67 µm2 and surface roughness of 1.199 µm, was obtained using TLBO technique. Further improvement for surface finish and corner accuracy in addition powder (3 g/L) with dielectric in WEDM process is found to be a value of 50.77% and 23.01%, respectively, compared with conventional WEDM process. SEM was employed to observe and analyze the topographical changes that occurred during powder mixed and without powder mixed in WEDM process.