For L-PBF (Laser Powder Bed Fusion) metal additive manufacturing (AM) the choice of available materials is still limited. 1.2709 maraging steel powders are widely used for injection molds and high-quality engineering parts. The quality of the parts produced by L-PBF are significantly affected by the process parameters. The aim of this research was to find optimal process parameters for producing 1.2709 tool steel at a layer thickness of 20 µm and to reveal the possible parameter settings yielding comparable build quality as the “EOS surface” parameter set at a layer thickness of 20 µm. Findings showed that too low or too high input energies produce improper parts. A large range of parameters produce good quality parts, of which the optimum parameters can be chosen.

Custom-made subperiosteal implants are increasingly used in clinical cases where significant bone loss due to trauma or disease renders conventional endosseous implant placement unfeasible. This study investigated how different internal structural designs affect the deformation and stress distribution in mandibular subperiosteal implants under clinically relevant loading conditions. An idealized implant geometry was defined based on average human mandibular dimensions, and four configurations with identical outer shape and connection features were created, differing only in sidewall architecture (solid, top-relieved, top-relieved with lateral perforations, and top-relieved lattice framework). All specimens were manufactured by metal additive manufacturing and evaluated using cone-beam computed tomography (CBCT). Mechanical testing was performed in two stages: (i) cyclic loading consisting of 500 bite cycles at an overall force of ~326–350 N and (ii) a single static high-load event of 2000 N, applied parallel to the fixation pin axes. CT datasets acquired before and after each stage were compared to detect permanent deformation. No measurable residual deformation was identified in any configuration; the only observed macroscopic change was an adhesive-bond limitation in one case, rather than structural yielding of the implant. Finite element analysis further supported these findings by identifying localized stress concentrations mainly at the implant–prosthetic interface and by revealing the load-transfer zones that govern the mechanical response. Overall, the results indicate that lightweight, perforated, and lattice-based internal designs can preserve global structural integrity across physiological and supra-physiological load ranges while enabling design optimization to improve stress distribution.

Laser powder bed fusion (L-PBF) enables the creation of advanced metal parts that are difficult to manufacture conventionally. In this study, the model parameters of the Johnson–Cook (JC) constitutive relation and the damage parameters of the JC failure model for 1.2709 steel produced via L-PBF were determined. Constitutive parameters were identified from quasi-static uniaxial tensile tests conducted on smooth specimens. In contrast, stress triaxiality-dependent damage parameters were determined using tensile tests on notched round bar specimens in combination with FEM simulations. The load–displacement curves showed good agreement with the experimentally obtained data. The strain–rate–dependent failure model parameter was determined by correlating Charpy impact test results with numerical simulations. Reasonable agreement between the simulation and experimental results was achieved. The results demonstrate that the proposed experimental–numerical framework provides a reliable basis for modelling both the quasi-static and impact fracture behaviour of L-PBF-fabricated 1.2709 steel.