An investigation into the effect of wire inclination in Wire-Electrical Discharge Turning process of NiTi-60 shape memory alloy

In this study, a novel method of Wire Electrical Discharge Turning (WEDT) by inclining the wire electrode is introduced. Response Surface Methodology (RSM) is employed to conduct the experiments by varying pulse-ontime, spindle rotational speed, and inclination angle at three levels, where Volumetric Material Removal Rate (VMRR) and the Average Surface Roughness (Ra) were considered as the response outcomes. It has been observed that the inclination of wire can improve the VMRR and Ra. The surface microstructure has also been studied with the help of FESEM images, and accumulations of elongated craters leading to the formation of crater-channels are observed. The formation of these crater-channels is influenced by the inclination angle and the spindle rotational speed. The observed surface cracks in the generated surface are very less in number and in some localized positions only. The study also focuses on arc-spark characteristics of voltage waveforms taken during the experiments. It is observed that at arcing conditions, a shiny surface is produced, and on the other hand, sparking conditions produce a dull and burnt surface. Finally, a multi-stage WEDT strategy is proposed to produce a cylindrical surface with high VMRR and superior surface characteristics.