3D Printed Shape Memory Alloy Wire Embedded Actuator

Thermoplastic Polyurethane is best known for its elastic and flexible qualities. 3D printing of polyurethanes is well-evolved research for various applications including soft robotics, actuators, and origami structures. In this research, we developed a polyurethanes-based composite actuator that uses commercially available nickel-titanium alloy - Nitinol shape memory alloy. The Nitinol wire is embedded within a 3D-printed thermoplastic polyurethane substrate. 3D printing “Pause and Go” approach is used to add the pause during the printing of the specimen and insert the SMA wire. After embedding the wire, printing is continued to complete the fabrication of the specimen with embedded wire. Several design configurations were fabricated in the exploratory research to understand the impact of the geometry on the actuation. Through the experimental characterization, we observed the actuation due to external thermal and electrical stimulation. The embedded SMA regained the treated shape which ultimately demonstrated the actuation. This research explores the low-cost manufacturing of soft robotics elements which can be used in many real-life applications in medical, aerospace, and domestic appliances.