Development of a 4D-Printed PLA Microgripper

Ever since its debut in 2013, four-dimensional (4D) printing has gained popularity among the fabrication industry and academia alike. It was first proposed as a method for self-assembly but was later redefined as a technology that allows printed objects to shape-shift while being exposed to the environment. This paper proposes a novel method to fabricate a 4D-printed microgripper utilizing the shape memory effect of polylactic acid (PLA), which is a shape memory polymer. Finite element analysis is carried out to investigate the microgripper’s movement, which operates based on the actuation of beam-like structure. The self-bending capability due to the release of internal pre-strain of printed materials is used to simulate the actuation of the structure. The microgripper consists of two active beams that can be stimulated at 85 °C, while the rest of the microgripper is passive. Fused deposition modeling is used to fabricate the active and passive parts of a microgripper, where different printing parameters were used for each part. The microgripper fingers achieved an actuation distance of 3 mm for the actuators’ deformation distance of 3.925 mm each, giving a ratio of 0.76 in the two distances. The results show that the developed microgripper has a high potential to be miniaturized and implemented in various biomedical and micromanipulations applications.