Prediction Surface Roughness in High-Speed Milling of Inconel 718 under Mql Using Rsm Method

Abstract

This paper investigates the effect of cutting speed, feed rate, and depth of cut on the surface roughness of Inconel 718 when milled under minimum quantity lubrication. The response surface methodology (RSM) was employed in the experiment, and a Box–Behnken design was used to determine the cause and effect of the relationship between the control variables and the response. The investigated milling parameters were cutting speed (100, 135, and 170 m/min), feed rate (0.15, 0.2, and 0.25 mm/rev), and depth of cut (0.6, 0.8, and 1.0 mm). The results showed that the interaction between the feed rate, fz, and the radial depth of cut, ae, was the primary factor controlling surface roughness. The responses of various factors were plotted using a three-dimensional surface graph. The quadratic empirical models were developed with a 95% confidence level. The optimum condition required for minimum surface roughness include cutting speed of 136 m/min, feed rate of 0.1 mm/rev, axial depth of cut of 0.5 mm, and radial depth of cut of 1.38 mm. With this optimum condition, a surface roughness of 0.117 µm was obtained.