Mapping Uncertain Surface Roughness of Inconel 718 in WEDM

Wire EDM process has gained popularity in the industry due to its potential of producing complex miniaturized geometry with accuracy. Besides, WEDM is a burr-free machining process with minimal chances of tool failure which provides it an edge over conventional machining processes. However, the fluctuation in the pulse power supply, uncertain frictional and other forces acting on the wire, control actions, dynamic gap state, and interaction between the process variables during the WEDM process tend to randomize the process parameters and cause fluctuation of the performance parameters a lot. Thus, this paper quantifies the effect of parametric uncertainty on the WEDM performance feature. To carry out the analyses, a multiple linear regression (MLR) model is constructed and further validated with the help of a scatter plot. The model exhibits appreciable prediction capability, i.e., a high coefficient of determination (R² = 0.89) and a low root mean squared error (RMSE = 0.41). With adequate confidence in the constructed multiple linear regression (MLR) model, the model is further employed to predict the response quantity for 10,000 samples generated using Monte Carlo simulation (MCS) to quantify the uncertainty. The effect of both individual and compound variations of process parameters, including the wire tension, discharge current, wire speed, and pulse on time on the crucial output quantity of interest (QoI), i.e., the arithmetic mean roughness (AMR), is portrayed. Further, sensitivity analysis depicts that discharge current (I) is the most predominant stochastic parameter affecting the response quantity. Wire speed (WS), pulse on time (Ton), and wire tension (WT) are equally sensitive.