Parametric modeling and optimization for abrasive mixed surface electro discharge diamond grinding of Inconel 718 using response surface methodology

摘要

Nickel-based superalloy, Inconel 718, owing to its superior high-temperature strength, excellent fatigue, and corrosion resistance, has been widely used in the aerospace industry. However, there are inherent problems associated with the conventional machining of Inconel 718 superalloy. Therefore, in this work, investigation on machining of Inconel 718 using a hybrid machining process called abrasive mixed surface electro discharge diamond grinding (AMSEDDG) has been presented. In AMSEDDG, abrasive particles are mixed in a dielectric fluid and surface electric discharge diamond grinding (SEDDG) is performed on the workpiece. Preliminary comparative experimentation for AMSEDDG of Inconel 718 resulted in better performance in terms of material removal rate (MRR) and average surface roughness, compared to the performance of electro discharge machining, electro discharge grinding, and SEDDG. The response surface methodology approach has been used for performing and analyzing the experiments to explain the influences of four control factors, including the wheel speed, abrasive concentration, current, and pulse on time, on the performance measures of MRR and average surface roughness. The models established were found to be trustworthy representatives of the experimental results with prediction errors less than +/- 5%. The results represent that the addition of abrasives in dielectric has a significant effect on both performance measures. The desirability function approach for optimizing the process performance resulted in MRR of 14.45 mm(3)/min and average surface roughness of 2.621 mu m for optimum settings of control factors, viz., wheel speed of 1355 RPM, abrasive concentration of 4 g/L, current of 6 A, and pulse on time of 22 mu s.