A method for the design and fabrication of heterogeneous objects

Layered Manufacturing (LM), also referred to as Solid Freeform Fabrication (SFF), is emerging as a new technology that enables the fabrication of three-dimensional heterogeneous objects. To take full advantage of this capability, a new method to design and fabricate heterogeneous components has to be developed. This paper introduces an integrated design and fabrication system for heterogeneous objects, especially Functionally Graded Materials (FGMs). We first describe the variant design paradigm and a constructive representation scheme for heterogeneous objects. A discretization-based process planning method, which converts continuous material variation into stepwise variation, is then described. Next, Direct Metal Deposition (DMD), a laser-based LM method that can take advantage of the proposed process planning method, is described in detail. Finally, examples are shown to illustrate the entire design-fabrication cycle for heterogeneous objects.