Time-dependent motion of 3D-printed soft thermal actuators for switch application in electric circuits

Abstract

We present a reversible and three-dimensional (3D)-printed soft thermal actuator (3-STA) and transient analysis for electrical switch applications. The actuating performance as a switch was numerically modeled to predict the transient motion of the 3-STA. For simple fabrication, polylactic acid (PLA) filaments were directly printed onto a paper substrate. An electrical connection through the filament/paper composite was implemented to create the thermo-responsive soft actuator, which served as a switch. As a result, the 3-STA with 0.45 mm-thick PLA layer exhibited the most rapid (an average response time of 35.68 s) and stable actuation under 500 cycle tests. In addition, the developed model predicted the position of an actuator body well at a specific time and was comparable with the experimental results. The step current was successfully generated by delayed contacts between the actuators and pin headers, thereby controlling the electric power, which can be used for electrical components (e.g., a cooling fan). These results support the simple fabrication of an electrical switch through 3D printing and the development of transient analysis to estimate the position of soft actuators at a specific time.