Investigation of the Effect of FDM 3D Printing Parameters on Conical Shape Recovery in the 4D Printing Process

4D printing is an emerging technology in which the printed parts can change their shapes when exposed to an external stimulus. In this research, a relationship between the pre-stress stored in the printed discs and the amount of shape recovery was obtained using FE simulations. Then, the effect of layer height, bed temperature, nozzle temperature, and printing speed on the amount of pre-stress applied in the printed discs based on polylactic acid material in the Fused deposition modeling 3D printing was investigated. In this paper, 27 experimental tests were performed using a central composite design, and modeling was done with the least cost and time and the most reliability and accuracy. Then a relationship between the mentioned parameters and the amount of pre-stress applied to the printed discs was obtained. R2 and Adj R2 of the model were obtained more than 99% which shows the high accuracy of the model. In order to validate the experimental model, simulation and experimental tests were carried out in the conditions of the highest amount of shape recovery. The results showed that the experimental model error is 5.9% and the error between the applied pre-stress and the amount of shape recovery is 2.95%.