Laser-based powder-bed fusion strategies for the fabrication of cellular structures with a fine resolution

Abstract

Laser-based powder-bed fusion (L-PBF) is an additive manufacturing technology that is capable of fabricating net-shaped intricate metallic designs, such as cellular structures, with tailored mechanical properties. Ideally, these cellular structures replicate the human cancellous bone structure for proper bone tissue engineering applications. In this study, we present novel laser scanning strategies and their associated L-PBF processing parameters to fabricate Ti-6Al-4 V cellular structures with a fine resolution to mimic the resolution of human cancellous bone and improve their mechanical performance. In this study, three L-PBF scanning strategies with various laser powers and scanning speeds were defined to fabricate diamond and dodecahedron unit cells with four different cell sizes. With a constant laser spot size of ~80μm, average powder size of 34μm, and layer thickness of 30μm for all the L-PBF processes, the finest achieved resolution for the struts of the cellular structures was 120μm in this study. Furthermore, correlations between the L-PBF processing parameters/scanning strategies and physical/mechanical properties of the cellular structures were comprehensively investigated and are discussed for bone tissue regeneration. In conclusion, the porosity and mechanical properties of several fabricated dodecahedron cellular structures and those of human cancellous bone demonstrated significant similarities, e.g., a porosity of 72.6–87.4%, compressive strength of 0.1–30 MPa, and elastic modulus of 0.01–3 GPa.