Investigating the impact of infill patterns on shape memory effect in material extrusion

Extensive research has been conducted on Shape Memory Polymers (SMPs) for their potential application in additive manufacturing. The Shape Memory Effect (SME), a key attribute of SMPs, enables 3D-printed objects to alter their shape in response to external stimuli. Several methods for programming SMEs have been explored, such as modifying printing parameters like infill patterns or density. However, incorporating SMPs as substitutes for conventional functional components has been challenging due to grafting difficulties and the limited reliability of SMEs. In this research, the influence of internal structures on SMEs is examined by comparing the full shape recovery period. This investigation has revealed the impact of different infill structures on SMEs and uncovered a complex shape recovery pattern termed multi-phased SME. This occurs when straight infill structures are nearly parallel along the length of a cuboid specimen that has been programmed to form a 90° curve. This finding enhances the creation of complex shape recovery behaviours by simply modifying printing parameters and is applicable to a variety of SMPs.