Impact of design strategy favoring powder removal on mechanical performance of bio-inspired porous architectures for laser-based powder-bed fusion additive manufacturing

Abstract

Mass reduction is a concern both in mechanical engineering and living organisms to reduce energy and materials consumption. Lately, transfer of knowledge from biology to engineering has become easier thanks to additive manufacturing. Trabecular bone for example optimally adapts to the mechanical stress it undergoes. Mass reduction methods bio-inspired from trabecular architecture, proposed in the literature, are not always applicable for laser-based powder-bed fusion. In particular, bio-inspired mass reduction methods based on a material removal principle generate porosities throughout a solid initial part which can result in enclosed porosities that trap un-melted powders. Here, we propose a 3D depowderable bio-inspired mass reduction method. Powder removal was controlled in different samples through weighing and X-ray computed microtomography and the impact of the design strategy that ensures correct powder removal on mechanical performance (stiffness) was quantified. Mean performance difference is 10.35 % (between 1.82 % and 26.47 %). For stiff and light parts loaded in bending, the proposed method outperforms parts made of bulk steel alloy by leveraging an architecture bio-inspired from trabecular bone.

Keywords

• Additive manufacturing
• Powder bed fusion
• Powder removal
• Bio inspiration
• Light-weight structure