Geometric assessment of lattice materials built via Selective Laser Melting

Selective Laser Melting (SLM) is a technology that allows for the realization of metallic porous solids that cannot be produced with other methods. Nevertheless, a geometric discrepancy between the as-designed and as-built part is a well-known issue that can be critically important for biomedical metallic lattices with pore size and strut thicknesses of a few hundred microns. In practice, any geometric imperfection introduces a degree of uncertainty that can alter the mechanical properties of the as-built lattice. A quantitative relationship between the as-designed geometry and the real geometry is a very useful design tool because it makes possible to predict the final morphology of the lattice by considering the manufacturing errors: a more predictable geometry of the lattice structure means more predictable mechanical properties of the implant. In this work, we investigate the relationship between the as-designed strut thickness and the printed strut thickness for regular cubic cell lattices. The joints between the struts are filleted to reduce the stress concentration and increase fatigue resistance. The size of the unit cell is scaled to find the smallest radius which can be accurately reproduced. Moreover, we also studied the effect of the printing direction on geometrical accuracy. (C) 2018 Elsevier Ltd. All rights reserved.