Investigation on anisotropy according to printing conditions for projection type photo-polymerization 3D printing

Recently, 3D printing has obtained increasing attention, and extended its application from the traditional rapid prototyping to direct fabrication of functional parts. To be used as the direct fabrication process, however, 3D printing should overcome drawbacks due to its lamination process: low dimensional accuracy, long fabrication time and degeneration of mechanical properties along the lamination direction. This degeneration along the lamination direction results in anisotropic mechanical properties, which prevents appropriate prediction of structural safety of the 3D-printed parts. This study investigated mechanical properties of 3D-printed parts using a mask-projection type (digital light processing; DLP) 3D printer by comparing tensile test results for the specimens that were printed along horizontal and vertical directions. By analyzing experimental results, appropriate printing conditions could be obtained to satisfy high mechanical strength and stiffness as well as to maintain mechanical properties within isotropic range.