Effects of Manufacturing Parameters on Fast Actuation of Twisted and Coiled Polymer Actuators Made of Fishing Lines

Twisted and coiled polymer actuators (TCPAs), typically made from fishing lines or sewing threads, became increasingly popular across various applications due to their unique capacity to contract or twist when heated, mimicking the behavior of artificial muscles. Their performance can be highly variable due to some manufacturing factors like fishing lines diameter. The study investigates TCPAs’ mechanical behavior, considering changes in the diameters of fishing lines, operating temperatures, and applied tensile forces. For this purpose, this study addresses these challenges by experimenting with TCPAs of different diameters (0.5, 0.7, and 0.8 mm), using a hot water circulation system to control actuator temperature, enabling rapid and consistent actuation. Testing TCPAs under various thermal conditions reveals that both displacement and tensile strokes increase with temperature and decrease with tensile force. Also, the TCPA with a 0.7 mm diameter which has the smallest coil spring index and the smallest coil bias angle achieved the best performance, with a maximum displacement of 17 mm and a tensile stroke of 7.65% at 80°C and 1.422 N. These findings provide a clear pathway for creating reliable, high-performing TCPAs, making them suitable for applications requiring precise and consistent actuation.