Additive Manufacturing, particularly Laser Powder Bed Fusion (PBF-LB/M), has transformed the production of complex metallic structures, enabling applications in smart reactors where enhanced heat and mass transfer at minimal pressure drop are critical. Triply Periodic Minimal Surface (TPMS) structures, such as Gyroid-TPSf and Schwarz-Diamond-TPSf geometries, offer high surface area-to-volume ratios, tunable porosity, and zero mean curvature, but their manufacturability via PBF-LB/M remains largely unexplored for demanding process-engineering applications.
In this collaborative study, the researchers from the Institute for Industrialization of Smart Materials, the Fraunhofer IAPT, and the Institute of Multiphase Flows at TUHH investigate the design and manufacturability of TPMS structures using 316L stainless steel via PBF-LB/M, focusing on the interaction of porosity, unit cell size, and sheet thickness. Using numerical simulations, experimental validation, and process optimization, practical design guidelines are developed. The design parameters of Gyroid-TPSf and Schwarz-Diamond-TPSf samples include porosities ranging from 70 to 90% and unit cell sizes from 2 to 20 mm. The results indicate that specifically, at large unit cell sizes (e.g., 20 mm), the decreased curvature radius reduces self-supporting effects, leading to insufficient mechanical stability during printing and resulting in local deformation. Conversely, at small unit cell sizes combined with high porosity levels (e.g., 2 mm and 90%), the sheet thickness becomes critically thin, often below the printable resolution, resulting in incomplete or fragile structures. CFD simulations were validated against experimental data across various volume flow rates.
Serhan Acikgöz, Christoph Wigger, Timo Merbach, Felix Kexel, Maria Isabelle Maiwald, Dirk Herzog, Ingomar Kelbassa, Michael Schlüter (2026). Design guidelines for laser powder bed fusion of triply periodic minimal surface structures for applications in smart reactors. Prog. Addit. Manuf., in press.
