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Modeling and simulation of burr formation - State of the art and future trends

Modellierung und Simulation von Gratbildung - Stand der Technik und zukünftige Trends
: Leopold, J.; Freitag, H.; Hoyer, K.; Schmidt, G.

Neugebauer, Reimund ; Fraunhofer-Institut für Werkzeugmaschinen und Umformtechnik -IWU-, Chemnitz; International Institution for Production Engineering Research -CIRP-, Paris:
8th CIRP International Workshop on Modeling of Machining Operations 2005. Proceedings : May 10 - 11, 2005, Chemnitz, Germany
Zwickau: Verlag Wissenschaftliche Scripten, 2005 (Berichte aus dem IWU)
ISBN: 3-937524-24-X
International Workshop on Modeling of Machining Operations <8, 2005, Chemnitz>
Conference Paper
Fraunhofer IWU ()
burr formation; simulation; finite element method; analytical method; visioplasticity; Gratbildung; Simulation; Finite-Elemente-Methode (FEM); analytische Methode; Visioplastizität

Higher precision of manufactured parts and surfaces, reduction of processing time with simultaneous increase of tool life and fully automated production are the major aims of research and development in the field of cutting. In order to fulfill the high demands and in addition to ensure high process reliability, new methods for theoretical investigations are required A phenomenon similar to the formation of chips is the formation of burrs at the end of a cut. Burrs are undesirable because they present a hazard in handling machined parts and can interfere with subsequent assembly operations From the simulation point of view, most modeling efforts remain with 2-D orthogonal cutting and describe only steady-state cutting. The importance of final state of cutting, tool exit, which creates burrs and other edge defects has been largely ignored. The Finite Element Method has been successfully applied in the last years and a new a days MOlecular Dynamics simulations of nanometric cutting where conducted under different cutting conditions to investigate burr formation and exit failure in metals. Several analytical approaches were attempted but were still based on experimental observation mixing theory of plasticity and geometrical Description of burr formation. The lack of precise material models describing material behavior under high strain rate and included size effects blocked further pursuit of analytical modeling of burr formation with theory of plasticity and pushed it in the direction of geometrical conformation theory with energy balance.
So, the paper will consider the state-of-the-art in burr modeling and simulation at first from the theoretical point-of-view, starting with numerical models and coming up to analytical models. In the second main part, new trends will be pointed out - e.g. burr simulation in multilayered materials, crack initiation implementation, the "hydrostatic bowl" formulation, cutting-tool (geometry and dynamics) and friction influence and finally some aspects to consider size effects in process scaling to improve burr formation models. Finally aspects of measuring technique to verify the theoretical models will be pointed out.