Cutting forces and their modelling in plunge milling of magnesium-rare earth alloys

Plunge milling is a machining process already recognised as able to afford significant gains in productivity during the roughing phases, especially in the case of deep workpieces. It is generally used for machining hard materials but more rarely for light alloys, especially for magnesium alloys. This paper deals with the study and the modeling of cutting forces in plunge milling of magnesium-rare earth alloys. In this study, the authors consider the case of a dry plunge milling process applied to two wrought Mg-Zr-Zn-RE alloys and one cast Mg-Zr-Zn-RE alloy, that are representative of magnesium-rare earth alloys in aerospace industry. This paper investigates the influence of cutting parameters and the influence of edge radius on cutting forces. An analytical model is set up so as to satisfactorily predict the cutting forces for these three representative magnesium alloys studied using just three instrumented tests. An experimental validation through different plunge milling tests shows good agreement between the model and the measured values in a wide range of cutting conditions.