Finite element modeling of chip separation in machining cellular metals

Cellular metals and metal foams belong to a young material group. Although it is desired to manufacture near-net-shape parts of cellular metals by primary shaping processes, additional secondary machining operations are often unavoidable to obtain the required geometries and quality demands. Nevertheless, conventional machining of cellular metals leads to undesirable surface damage and poor precision. Furthermore, the chip formation and the mechanism description of the surface damage are still unclear. A mesoscopic finite element model was developed to simulate the chip formation process in machining cellular metals. Experimental data of orthogonal machining tests were used to validate the finite element model. The cutting and thrust forces, as well as the images of the chip formation process of both experiments and simulations were compared and analysed. The model enabled the analysis of the chip formation and the surface defect mechanisms. The rake angle and cutting conditions affected the chip formation process, but the cell arrangement was detected as a decisive factor in the chip formation and the resulting surface damage.