Pattern-driven 4D printed PLA actuators

Abstract

Four-dimensional (4D) printing is a technology that allows fabricating complex structures that have the ability to change their shape based on various stimuli. Such structures are printed using smart materials, which mainly rely on shape memory polymers. Controlling the response of 4D printed structures becomes challenging when increasing the complexity of the design. This paper investigates the effect of the printing patterns on the deformation performance of polylactic acid (PLA) actuators. The actuators are printed using the fused deposition modelling method. Four different patterns, namely, rectilinear, grid, honeycomb, and triangular patterns are used to develop eight actuators' designs. The size of the patterns was varied in order to print the actuators using different infill percentages. The PLA actuators are activated using hot water of 85°C. The results show that the bending angle of the actuators is varied between 3.00° and 16.80°. The bending direction is affected by the size of the printing pattern, where the actuators bend towards the pattern with the bigger size. The results show that the proposed concept can be used in various pattern-based 4D printed robotics applications, where the actuation performance is tuned using the printing patterns, as well as the printing parameters.