Acoustophoretic Polishing During Stereolithography 3D Printing of Viscoelastic Nanoparticle Suspensions

28 pagesSupplemental file(s) description: Code for the acoustic agitation.In this work, we report an acoustic agitation approach to enhance the flow of yield stress fluids during inverted projection stereolithography (SLA) 3D printing. The enhanced flow resulted in a reduction of “over-curing” of previously printed layers, with the overall effect of higher resolution printing during inverted SLA. To elucidate the mechanism of the enhanced flow, we numerically simulated the acousto-mechanical coupling in the SLA resin feed system at different agitation frequencies. From the simulations, the resulting acoustophoretic flow had a peak enhancement at 110 Hz. Using these results, we printed nanoparticle suspensions under acoustic agitation and compared their surface fidelity with the intended CAD attributes, as well as compared to a simple pseudoplastic fluid (no nanoparticles, no yield stress). The overall effect is that our acoustophoretic polishing improves the printed feature resolution by over 25% compared to the normal inverted SLA process for yield stress fluids