Effective parametric analysis of machining curvature channel using semicircular curved copper electrode and OHNS steel workpiece through a novel curved EDM process

Abstract

Electro-discharge machining (EDM) is one of the advanced non-conventional machining techniques used in industries. Most of the EDM research areas are directed towards the linear movement (up-and-down) of the electrode. Through a novel innovation, an innovative way of machining a curvature channel through a semicircular curved copper electrode is possible through curved EDM process. The experimental setup is developed and installed on the Z-axis numerically controlled(ZNC)EDM machine. The oscillating motion of curved electrode on stationary workpiece is obtained by implementing the concept of mechatronics. In this present work, we attempt to investigate the effect of input machining parameters on the output performance characteristics in curved EDM process. During pilot experimentation, critical variables are identified and selected as sparking current, pulse on time, pulse off time and angular sensitivity. Design of Experiment using Taguchi (L9) is used to formulate the planned experiments and to evaluate the effects of input machining characteristics on Material Removal Rate (MRR), Electrode Wear Rate (EWR), Curved Machining Angle (CMA), and Curvature Depth (L). Regression analysis and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) are effectively used to validate the model developed for the curved machining. The results obtained after experimentation predicts that the model can be accepted to optimize the quality machining characteristics in curved EDM process. Geometrical analysis and surface roughness are evaluated for the machined curvature through the advance measuring equipment’s. Scanning Electron Microscopy (SEM) is also used for observing the microstructure at higher magnification of workpiece material before and after machining.