Process parameters optimization and mechanical properties of 3D PLA/HA printing scaffold

Abstract

This research aimed to study the mechanical properties, specifically the compressive strength of Polylactic Acid (PLA)/Hydroxyapatite (HA) cell scaffolds obtained by 3D printing, and to find the relationship of factors used in the synthesis of PLA/HA cell scaffolds obtained by 3D printing. The PLA/HA filaments with glycerol as a binder were formed at an optimal condition of tensile strength by 5 wt% HA and a melting temperature of 170 °C with a screw rotation speed of 25 revolutions per minute. The highest tensile strength of synthetic filaments was 35.12 MPa. Then, the central composite design was designed using three factors, nozzle temperature, printing speed, and the density of the forming specimens. Then, 3D-forming specimens were fabricated to be examined for compressive strength. Effective factors and optimal levels were analyzed by Minitab statistic software. The optimal factor level was refabricated, and the annealed process was also applied to improve its mechanical properties. Annealed and Unannealed specimens’ compressive strengths were compared. The results showed that a nozzle temperature of 215 °C and a part density of 100% had the most affected on maximum compressive strength at 65.62 MPa. The printing speed had no significant effect. Furthermore, a differential scanning calorimeter (DSC) was used to study the properties and the degree of crystallinity of PLA. The result found that the crystallization of a PLA was increased by an annealing treatment that affects heat resistance and also increases compressive strength by 11.60% compared to unannealed specimens.