Analytical Modeling of Chip Geometry in High-Speed Ball-End Milling on Inclined Inconel-718 Workpieces

Most often contoured surfaces inclined at several inclinations are generated using ball-end milling of aerospace and automobile components. It is understood that the chip morphology and the corresponding cutting mechanisms change with a change in the tool-workpiece interactions on inclined surfaces. Analytical predictive models to accurately evaluate the undeformed and deformed geometries of chip in ball-end milling are not available. Therefore, this work presents development of analytical models to predict the cutting tool-workpiece interaction as the workpiece inclination changes, in terms of undeformed and deformed chip cross sections. The models further evaluate instantaneous shear angle along any cross section of the tool-work interaction on a ball-end cutter in a milling operation. The models illustrate evaluation of a chip segment and mechanism of its formation in ball-end milling on an inclined work surface. It is observed that the chip dimensions, except deformed chip thickness, increase with an increase in the workpiece inclination angle. Also, a higher workpiece inclination results into an easy flow of the deformed chip over the cutting tool flank, which leads to a higher shear angle during the cut. The predictive chip geometry models corroborate 90% to the experimental results obtained at various workpiece inclinations.