4D printing of shape memory polylactic acid beams: An experimental investigation into FDM additive manufacturing process parameters, mathematical modeling, and optimization

4D printing is a novel process, which is referred to as the future of additive manufacturing. The main goal of 4D printing is to control the final shape in terms of quality (type of deformation) and quantity (amount of defor-mation) over time. In this study, the response surface method (RSM) has been used to develop a model for controlling the amount of Polylactic acids (PLA) torsional and flexural deformation in 4D printing. The model examines the effect of FDM parameters such as layer height, print speed, and nozzle diameter. Using the central composite design (CCD), high-order models were developed to calculate the optimum operating conditions with high accuracy compared to the experimental results. By achieving optimum printing conditions, the maximum amount of torsional and flexural deformation was achieved. The values of layer height, print speed, and nozzle diameter for both flexural and torsional modes were 0.05 mm, 112 mm/s, and 0.4 mm, respectively.