Influence of Nanofiller Size and Concentration on the Photo-Induced 3D Printing Performance of Elastomer Composites

Digital Light Processing (DLP) 3D printing has attracted considerable attention owing to its high fabrication speed and excellent printing resolution. However, pure polymer resins commonly used in 3D printing often suffer from limited functionality, primarily owing to their poor mechanical properties. To overcome the limited functionality of polymer resins, nanofiller-reinforced resin composites have been extensively studied. Yet the effects of nanofillers on DLP 3D printing remain insufficiently understood. In DLP 3D printing, the size and concentration of nanofillers influence the viscosity and light-scattering behavior of the resin under 405 nm light. These changes result in mechanical properties and printing accuracy that differ from those observed in conventional thermally cured molding processes. Therefore, this study systematically investigates the effects of nanofiller size and concentration on mechanical strength and printing accuracy from rheological and optical perspectives. Medium-size nanoparticles (400 nm) exhibited the highest mechanical strength due to the increased curing depth resulting from Mie scattering. Larger nanoparticles (1000 nm) gave the highest printing accuracy owing to their weaker contribution to resin viscosity. The smallest nanoparticles (200 nm) showed the lowest mechanical strength and printing accuracy owing to the substantial increase in resin viscosity and light reflection. These findings provide practical guidelines for optimizing nanofiller selection in vat-photopolymerization systems.

Keywords: Nanofiller, DLP 3D printing, size effect, concentration effect