Dynamic simulation of milling operations with small diameter milling cutters: effect of material heterogeneity on the cutting force model

Simulation of manufacturing processes (also called virtual manufacturing) is an important research topic in order to optimize the added value of the manufacturing chain. The mastering of these techniques allows companies to remain competitive on the market. Machining operations are very complex to simulate numerically due to the severe conditions undergone by the material (high strain, very high strain rates, high temperature,...). In addition, the rising need of micro-manufacturing techniques creates new challenges in numerical simulation. Indeed, some physical phenomena neglected for traditional machining simulation need to be taken into account for accurate simulation when the feedrate is fairly low (size effect, minimum chip thickness, material heterogeneity,...). New developments are thus needed to unlock the full benefits of these techniques. The aim of this paper is to enhance the classical mechanistic cutting force model for milling operations with small diameter tool by considering the effect of the heterogeneity of the material. The variability of the response during a test on fixed conditions (cutting tool, machined material and cutting parameters) is taken into account to develop a model whose parameters can evolve during a given operation. The statistical dispersion of cutting forces observed during experimental test is measured and modeled as a random perturbation of the force. The effects of this perturbation on the stability of milling operations are then demonstrated by means of numerical simulation.