Design and manufacturing of high-performance prostheses with additive manufacturing and fiber-reinforced polymers

This paper presents an approach combining additive manufacturing (AM) with carbon fiber reinforced polymers (CFRP) in an autoclave prepreg process for the development of complex-shaped hybrid AM-CFRP structures with the potential for individualization. The goal of this paper is to investigate the processing route in the context of low volume industrial applications and to assess the mechanical performance of hybrid AM-CFRP structures in ultimate strength and fatigue. The approach was applied to lower-limb prostheses using dissolvable in-autoclave tooling made of ST-130 by fused deposition modeling, two load introduction elements made of titanium by selective laser melting, and pre-impregnated carbon fiber reinforcements. The parts were cured in an autoclave at a pressure of 3 bar and a temperature of 110 °C. The inner toolings were dissolved in a basic solution after curing. The prostheses were subjected to ultimate strength and fatigue tests to assess the mechanical performance of the structures. Results show that the target load of 5474 N was exceeded by 40% and that no fatigue failure occurred for the given loading. Weight savings of 28% compared to a state-of-the-art aluminum reference part were achieved. Results demonstrate that the combination of technologies could be appropriate for high-performance lightweight components with complex geometries.