Influence of build geometry on the mechanical, thermal, and microstructural properties of PA12 manufactured by multi jet fusion

This study investigates the influence of build geometry on the thermomechanical, and microstructural properties of PA12 manufactured by Multi Jet Fusion, to establish a baseline dataset for future orthotic applications. Despite the increasing use of MJF PA12 in biomedicine, variability in reported properties limits reliable performance prediction. Standardized tensile and flexural specimens were printed in the X, Y, and Z build orientations, with Type 1B and 1BA tensile geometries used to assess the additional influence of section thickness. Mechanical testing, combined with thermal, spectroscopic, density, computed tomography, dimensional, and fracture-surface characterization to assess the influence of process-induced features. Results showed the MJF process preserved the chemical structure of PA12 while reducing crystallinity relative to the feedstock powder. Density and CT analyses revealed orientation-dependent porosity and geometric deviations, including characteristic sag. Flexural strength and modulus increased from X–Z orientation, while tensile behavior and ductility varied with build orientation and specimen geometry.