Mechanical behavior of 3D-printed PEEK and its application for personalized orbital implants with various infill patterns and densities.

This study proposed a 3D-printed PEEK with a specific design to restore the damaged orbit shape. Such printed personalized implants are greatly affected by the process parameters, wherefore the effects of the nozzle temperatures, printing speed and layer thickness on the tensile properties were investigated based on the Taguchi approach. The optimal mechanical properties, i.e., the tensile strength and Young's modulus, were found to be 54.97 MPa and 2.67 GPa, respectively. These properties were obtained by adjusting the nozzle temperature to its high level (450 °C), while the layer thickness (0.1 mm) and printing speed (20 mm/s) were set to their low levels. Secondly, the mechanical behavior of a personalized orbital implant with these optimized properties was evaluated via finite elements analysis with various infill patterns and densities, at three thicknesses: 0.3, 0.5 and 0.7 mm. It was found that all thicknesses were acceptable for the 100% filling. For the honeycomb pattern, the thicknesses 0.5 and 0.7 mm were satisfactory with a fill rate of 70% and 55% whereas only the thickness of 0.7 mm was suitable for the 40% filling. The honeycomb pattern with 40% filling and a maximum stress (7.186 MPa) and strain (0.00627 mm) should be beneficial for light-weight orbital implants.