An investigation into the effect of thermal variables on the 3D printed shape memory polymer structures with different geometries

In this paper, the effects of thermal parameters including the deformation temperature, shape recovery temperature, and heating rate on the shape recovery of a specific rounded rectangle structure were investigated using the design of experiments. Three-point bending thermo-mechanical tests were subsequently carried out where water was used for controlling the temperature. It was found that the deformation temperature and heating rate have the most and the least effect on the shape recovery of polylactic acid (PLA) SMPs, respectively. The mathematical modeling results showed that the optimum condition of the highest shape recovery is obtained at the deformation temperature of 53.31°C, recovery temperature of 59.94°C, and heating rate of 8.05°C/min. It was also observed that the shape recovery of the specified rounded rectangle structure manufactured by the 3D printing method was enhanced from 93.03% to 98.14% by optimizing the thermal parameters. Besides, the optimum condition was applied to structures with different cell geometries and it was shown that the obtained condition was also enhanced the shape recovery of structures with diamond and honeycomb. More specifically, the shape recovery of noted structures was significantly enhanced to 98.00% and 97.71 % from 82.86% and 78.89%, respectively.