4D Printing and Characterization of Shape Memory Polymer (SMP) Based Smart Gripper

Shape Memory Polymer (SMP) is stimuli-responsive material with the ability to recover the original shape from a deformation upon triggering by an appropriate stimulus like heat, light, and electricity. The shape recovery properties can be harnessed through 4D printing of self-recoverable functional structures and made usable in fields like medicine and robotics. To investigate the recovery properties, best printing parameters and optimal sizes, 4D reconfigurable gripper designed in CAD was printed in Ultimaker 2 Printer. Different stencils were made in varying printing parameters of temperature, infill, speed and time. Analysis for the stencils proved best print quality at a temperature of 195 °C and nozzle retract speed of 40mm/s. Shape recovery characterization was done on MATLAB. A printing temperature of 203 °C, infill density of 38% and printing speed of 40 mm/s gave the gripper with the best print quality. Characterization of the varying performances of the four grippers was attributed to the different infill percentages. The lower the infill, the higher the recovery rate due to the low stiffness of the gripper. The best recovery rate of 96.93% was associated with an optimal printing temperature of 203 °C.