Effect of print orientation on microstructural features and mechanical properties of 3D porous structures printed with continuous digital light processing

• Published in: Rapid prototyping journal Vol. 25; no. 6; pp. 1017 - 1029
• Main Authors: Navarro, Javier, Din, Matthew, Janes, Morgan Elizabeth, Swayambunathan, Jay, Fisher, John P, Dreher, Maureen L
• Format: Journal Article
• Language: English
• Published: Bradford Emerald Publishing Limited 21.08.2019; Emerald Group Publishing Limited
• Subjects: 3-D printers; Accuracy; Biaxial loads; Biocompatibility; Biomedical materials; Construction; Curing; Investigations; Light; Manufacturers; Mechanical properties; Medical device industry; Medical equipment; Microstructure; Optimization; Orientation effects; Pore size; Porosity; Process parameters; Rapid prototyping; Resins; Scaffolds; Shear tests; Shrinkage; Surface roughness; Three dimensional printing; Transplants & implants; Viscosity; Porous scaffolds; Print orientation; Biaxial loading; DLP; Stereolithography; Compression loading; 3D printing
• ISSN: 1355-2546; 1758-7670
• DOI: 10.1108/RPJ-10-2018-0276

Purpose This paper aims to study the effects of part orientation during the 3D printing process, particularly to the case of using continuous digital light processing (cDLP) technology. Design/methodology/approach The effects of print orientation on the print accuracy of microstructural features were assessed using microCT imaging and mechanical properties of cDLP microporous scaffolds were characterized under simple compression and complex biaxial loading. Resin viscosity was also quantified to incorporate this factor in the printing discussion. Findings The combined effect of print resin viscosity and the orientation and spacing of pores within the structure alters how uncrosslinked resin flows within the construct during cDLP printing. Microstructural features in horizontally printed structures exhibited greater agreement to the design dimensions than vertically printed constructs. While cDLP technologies have the potential to produce mechanically isotropic solid constructs because of bond homogeneity, the effect of print orientation on microstructural feature sizes can result in structurally anisotropic porous constructs. Originality/value This work is useful to elucidate on the specific capabilities of 3D printing cDLP technology. The orientation of the part can be used to optimize the printing process, directly altering parameters such as the supporting structures required, print time, layering, shrinkage or surface roughness. This study further detailed the effects on the mechanical properties and the print accuracy of the printed scaffolds.