A Comparative Study on the Influence of Annealing on the FDM-Printed PLA+ Mechanical Behavior

Previous studies had focused on examining standard materials for fused depositing modeling that were not designed to be improved by annealing and had used very limited temperature and time ranges. This study selected a material specifically formulated for annealing and examined a total of 20 ranges in two phases, allowing for a much higher degree of precision. Thus, the objective of this study is ascertaining the optimal temperatures and time for annealing on this material based on polylactic acid, commercialized as PLA+. The determination of each specimen is made by analyzing the data obtained from tensile, compression, and hardness tests. This allows the properties of each range to be compared with the material without heat treatment, enabling the best annealing options to be selected. Tensile testing demonstrated a 14.6% increase in elastic modulus at 85 °C after 25 minutes, although ultimate stress decreased by up to 7.0% after annealing. The results of the compression analysis indicated a limited modulus reduction (< 4.5%) alongside significant gains in elastic zone stress and energy absorption, which peaked at 90 °C after 15 minutes. Also, it was found that improvements in hardness were observed at higher annealing temperatures (90 °C for 15 minutes), resulting in an increase of up to 7% in comparison with the material that had not undergone the annealing process. In comparison with previous research, the utilization of PLA+ material has been demonstrated to yield superior enhancement following the process of annealing with a reducing time.