Design and Analysis of Lattice Structures for Additive Manufacturing

Additive manufacturing (AM) enables time and cost savings in the product development process. It has great potential in the manufacturing of lighter parts or tools by the embedding of cellular/lattice structures that consume less material while still distributing the necessary strength. Less weight and less material consumption can lead to enormous energy and cost savings. Although AM has come a long way over the past 25-30 years since the first technology was invented, the design of parts and tools that capitalize on the technology do not yet encompass its full potential. Designing for AM requires departing from traditional design guidelines and adopting new design considerations and thought structures. Where previous manufacturing techniques (computer numerical control (CNC) machining, casting, etc.) often necessitated solid parts, AM allows for complex parts with cellular and lattice structure implementation. The lattice structure geometry can be manipulated to deliver the level of performance required of the part. The development and research of different cell and lattice structures for lightweight design is of significant interest for realizing the full potential of AM technologies. The research not only includes analysis of existing software tools to design and optimize cell structures, but it also involves design consideration of different unit cell structures. This paper gives a solid foundation of an experimental analysis of additive manufactured parts with diverse unit cell structures in compression and flexural tests. Although the research also includes theoretical finite element analysis (FEA) of the models, the results are not considered here. As an introduction, the paper briefly explains the basics of stress and strain relationship and summarizes the test procedure and methods. The tests concentrate primarily on the analysis of 3D printed polymer parts manufactured using PolyJet technology. The results show the behavior of test specimens with different cell structures under compression and bending load. However, the research has been extended and is still ongoing with an analysis of selective laser melted test specimens in aluminum alloy AlSi10Mg.