Tool point dynamics prediction using a hybrid FE experimental modeling of milling machine

Vibrations produced by the coupling between machine tool dynamics and cutting forces can seriously limit productivity of milling operations. Therefore the prediction of forces between tool and workpiece is crucial in order to preserve process stability. In the last decades different cutting force models have been developed: despite the differences between the various approaches, it is practically universally assumed that cutting forces are related to uncut chip thickness. In this paper the first step of an innovative hybrid numerical-analytical method for uncut chip cross-sectional area calculation in 2.5-axis end milling operations is presented. This approach, once fully developed, will be able to identify cutting forces and final workpiece surface accurately, even in case of tool and workpiece vibrations (e.g. using slender tools or machining thin wall parts), avoiding time expensive finite element analysis of chip formation. In order to develop such system, a reliable algorithm able to calculate the instant chip thickness in the most general manner has to be provided. This paper will mainly present this model and show its higher accuracy compared to traditional and improved analytical approaches.