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Additive manufacturing (AM) is a smart manufacturing technique that fabricates components directly from 3-D models by selectively joining materials. This technology is revolutionizing the way products are created by reducing turnaround times, increasing viable component complexity, and enabling economic low-volume and mass-customized production. As this technology gains traction as a means of producing end-use components, focus has been placed on improving quality and consistency to ensure components can perform and their traditionally manufactured counterparts. This chapter will focus on selective laser sintering (SLS), an industrial AM technique for producing polymer components. Design guidelines will be presented that, when followed, improve the probability of creating high-quality components that match the design intent. SLS failure modes and process control will also be discussed to provide an understanding of how to properly build components. Incorporating the design guidelines and understanding machine control methodologies allow users to create high-quality components consistently.

Additive manufacturing enables the fabrication of metallic architected materials for structural applications. However, variability in the manufacturing process can contribute to various types of defects, which lead to mechanical properties that are much worse than predicted. Architected materials comprised of many small struts further exacerbate the process variability. The geometry and mechanical properties of individual struts differ from the bulk material, with the extent of the disparity related to the size and orientation of the struts with respect to the build platform. Small features are also more susceptible to process defects including porosity and surface roughness. Postprocessing operations such as hot isostatic pressing seek to alleviate some of these defects with minor success. This manufacturing uncertainty complicates the prediction of lattice structure performance, sometimes requiring computationally expensive stochastic finite element models informed by CT scanning to obtain accurate results. In this chapter, the effective mechanical properties of individual lattice struts are evaluated experimentally with a high-throughput tensile testing procedure. Then, these effective mechanical properties are incorporated into finite element models of the entire lattice structure. Results indicate that this approach yields accurate predictions of lattice structure properties without requiring CT scanning or computationally expensive stochastic finite element analysis.