A new approach to the design and optimisation of support structures in additive manufacturing

Support structures are required in several additive manufacturing (AM) processes to sustain overhanging parts, in particular for the production of metal components. Supports are typically hollow or cellular structures to be removed after metallic AM, thus they represent a considerable waste in terms of material, energy and time employed for their construction and removal. This study presents a new approach to the design of support structures that optimise the part built orientation and the support cellular structure. This approach applies a new optimisation algorithm to use pure mathematical 3D implicit functions for the design and generation of the cellular support structures including graded supports. The implicit function approach for support structure design has been proved to be very versatile, as it allows geometries to be simply designed by pure mathematical expressions. This way, different cellular structures can be easily defined and optimised, in particular to have graded structures providing more robust support where the object's weight concentrate, and less support elsewhere. Evaluation of support optimisation for a complex shape geometry revealed that the new approach presented can achieve significant materials savings, thus increasing the sustainability and efficiency of metallic AM.