Lightweight lattice structures in selective laser melting: Design, fabrication and mechanical properties

Lattice structures manufactured by selective laser melting (SLM) have received increasing interest in the scientific community over the last few years because of their advantageous stiffness-to-weight ratio, wide range of possible applications and their difficult producibility by other means of manufacturing. Many authors have addressed novel ideas for lattice structures, such as recoverable lattices, plate lattices or hierachical lattice structures for applications ranging from shock absorbers, heat exchangers, medical implants, acoustic dampers or lightweight engineering. This contribution addresses the rarely investigated influence of process parameters on the quality of the lattice and its resulting mechanical properties. A framework for the reliable and reproducible manufacturing of aluminum based truss lattice structures is presented selecting a suitable exposure strategy and determining the influence of the process parameters scan speed and laser power on the part quality. It is shown that the lattice strut diameter can be correlated to these process parameters through a simple scaling law. The influence of the process parameters during the SLM process on the lattice porosity, dimensional accuracy and resultant compressive behavior is investigated. Finally, the influence of the part position on the build plate on its mechanical properties is determined.