Mechanical behavior of calcium sulfate scaffold prototypes built by solid free-form fabrication

Abstract

Purpose This paper aims to investigate the mechanical behavior of three-dimensional (3D) calcium sulfate porous structures created by a powder-based 3D printer. The effects of the binder-jetting and powder-spreading orientations on the microstructure of the specimens are studied. A micromechanical finite element model is also examined to predict the properties of the porous structures under the load. Design/methodology/approach The authors printed cylindrical porous and solid samples based on a predefined designed model to study the mechanical behavior of the prototypes. They investigated the effect of three main build bed orientations (x, y and z) on the mechanical behavior of solid and porous specimens fabricated in each direction then evaluated the micromechanical finite-element model for each direction. The strut fractures were analyzed by scanning electron microscopy, micro-computed tomography and the von Mises stress distribution. Findings Results showed that the orientation of powder spreading and binder jetting substantially influenced the mechanical behavior of the 3D-printed prototypes. The samples that were fabricated parallel to the applied load had higher compressive strength compared with those printed perpendicular to the load. The results of the finite element analysis agreed with the results of the experimental mechanical testing. Research limitations/implications The mechanical behavior was studied for the material and the 3D-printing machine used in this research. If one were to use another material formulation or machine, the printing parameters would have to be set accordingly. Practical implications This work aimed to re-tune the control factors of an existing rapid prototyping process for the given machine. The authors achieved these goals without major changes in the already developed hardware and software architecture. Originality/value The results can be used as guidelines to set the printing parameters and a model to predict the mechanical properties of 3D-printed objects for the development of patient- and site-specific scaffolds.