Bio-Lightweight Structures by 3D Foam Printing

An innovative additive manufacturing technique is reported, which enables 3D printing of lightweight cellular structures with multiscale density control and carbon fibre reinforcement to improve mechanical performances. We present a model-based design of the process (including heat transport in the 3D printer nozzle) allowing to control the foam morphology in the printing process. The proposed approach is validated using polylactic acid, which is a bio-based compostable polymer employed in the biomedical, agricultural, and chemical engineering fields, that is blown with carbon dioxide to produce both reinforced foamed strands and structures. These have been characterized by microscopy and mechanical tests. The results show that the addition of fibres in the polymer matrix induces cells breakage resulting in a double-cell-sized morphology. The mechanical characterization of our 3D printed lightweight cellular composites revealed that the reinforced cellular structures have a higher compression strength than the non-reinforced ones.