Shape Memory Waterbomb Origami by Polylactic Acid Fused Filament Fabrication for Biomedical Devices
摘要
Origami, a traditional Japanese art, has influenced engineering and shape memory materials design, enabling complex structures from simple folds. Fused filament fabrication (FFF) using polylactic acid (PLA) presents new landscapes for shape-changing structures. PLA, with its relatively low glass transition temperature (i.e. 55–65 ℃), exhibits an activable shape changing behavior within easily accessible temperature ranges and, even not at the human body temperature, can be a valuable and available material to demonstrate the intent mechanism. In this paper we investigate how PLA's shape memory properties together with tool path extrusion strategies can be harnessed within the framework of origami-inspired structures. The waterbomb origami structure has been implemented to analyze folding and shape memory mechanism. The influence of 3 different activation temperatures of the mechanism as well as 3 different printing toolpaths were evaluated on a single cell. Five elements were arranged on a cylindrical shape to ideally achieve a portion of a tracheal stent with a small diameter during the insertion phase, which increases when in place. The results obtained demonstrate the potential of combining techniques used in origami and shape memory materials for reducing the initial volume of a part, which can be useful in many applications, such as stents in the biomedical field. By identifying a suitable material, the stent can be reduced in size, minimizing the invasiveness of the surgical procedure. Once inserted into the duct, the stent can unfold and adhere to the duct walls effectively.