Investigation in μ-WEDM of Inconel 625 superalloy using RSM-CCD technique

Micro wire electric discharge machining (mu-WEDM) has received immense attention due to the tight tolerance requirements of biomedical components and downsizing of sensors. The investigation reports the impact of wire material in machining Inconel 625 superalloy. The quality of machined surface is studied in terms of surface roughness (S-R) and erosion rate (E-R) by varying the mu-WEDM variables like servo voltage (S-V), pulse start time (T-start), angle of cut (A(C)), pulse stop time (T-stop) and current (I-C). Two different wire electrodes of diameter 150 mu m (brass and zinc-coated brass) are used in the study. Machining trials are executed by using central composite design (CCD). Further modeling of responses is carried out using Response Surface Methodology (RSM) and Desirability Analysis (DA) to predict the optimal machining parameters. The zinc-coated brass wire (W-zb) outperforms the plain brass wire (W-b) in terms of machining rate. Servo voltage is identified as a crucial and noteworthy parameter affecting the responses. The S-R is decreased by 28.13% at the highest value of S-V (70 V), while the E-R rose by 41.36% at the minimal value of S-V (50 V). The topography of machined surfaces is analyzed using SEM and 3D surface roughness images.

Automated summary

This study investigates the impact of wire material on the machined surface quality of Inconel 625 superalloy in micro wire electric discharge machining (mu-WEDM). By adjusting the machining parameters, the optimal parameters are predicted using Response Surface Methodology (RSM) and Desirability Analysis (DA). The results show that zinc-coated brass wire performs better than plain brass wire in terms of machining rate.