Automated Layer Decomposition for Additive/Subtractive Solid Freeform Fabrication

The new additive/subtractive technology (Shape Deposition Manufacturing) enhances Solid Freeform Fabrication (SFF) capability in producing near net-shape surface finish. This technology also builds parts in fewer layers compared with conventional layered manufacturing technology. However, to decompose a part into freeform layers usually requires expensive geometric computation. Also, to plan build sequences often requires human intervention because of the complicated spatial relationships among the freeform layers. At present decomposition and build sequence planning are both performed by experienced designers/users. In this paper, a novel decomposition approach based on surface splitting is proposed to facilitate computation and planning of the additive/subtractive SFF processes. The results shown in this paper are from models with 3D planar geometry. Continuous effort is devoted into extending and implementing this new approach for models with 3D freeform geometry.