Laser Powder Bed Fusion (LPBF) technologies (such as SLM or EBM) enable the realisation of intricate porous structures that would not be possible via traditional methods. However, the powder-based laser-path approach delivers features with poor surface finish. Intrinsic to the manufacturing, strut or sheet-based porous structures that possess small features also display “secondary roughness” which creates a discrepancy between the as-designed model (CAD) and the as-manufactured part [1]. Morphological features such as pore size, strut or wall thickness, and porosity are mostly impacted, and these consequently affect physical and mechanical properties such as strength, stiffness, and permeability, of great importance for multifunctional applications such as catalysts, and thermal exchange. The as-designed vs as-manufactured discrepancies impede the use of the former to predict the actual features of the latter [2]. This is problematic because the time and resources needed to validate the as-manufactured part are substantive, when it would be more convenient to rely on the as-designed model via trustworthy simulations. We are using post-processing (based on a novel chemical etchant deployed via perfusion) to remove the secondary roughness and bridge the gap between the as-designed and the as-manufactured part. In this way, the post-processed (actual) part and its as-designed counterpart possess similar morphological and physical properties, and this allows prediction of its behaviour faithfully in simulation, without exhaustive experimental validation. We have used a TPMS sheet-based gyroid printed using cp Titanium in an SLM machine as a case study that demonstrates how fluid-mechanical computation can inform the post-processing stage to treat as-manufactured lattice structures to such a level that the results from the as-designed model match those of the post-processed part. The gyroids were tested in-silico and experimentally and the results employed to establish a protocol that includes post-processing as part of the overall manufacture. REFERENCES [1] Torres-Sanchez C., Borgman J.M., Bell H., Sargeant B., Alabort E., Lindsay C., Conway P.P., ‘Comparison of SLM cpTi sheet-TPMS and trabecular-like strut-based scaffolds for tissue engineering’, Advanced Engineering Materials, 2022 24 (1), DOI: 10.1002/adem.202100527 [2] Khalil M., Burton M., Hickinbotham S., Conway PP., Torres-Sanchez C., ‘Simulation and physical validation of metal triply periodi