Static Liquid Interface to Reduce Support Structure Necessity in Top-Down Stereolithography

Stereolithography (SLA) 3D printing is a vat photopolymerization additive manufacturing process that utilizes photocurable resin, which requires sacrificial supporting structures on part overhangs, increasing material waste and post-processing time. This study details a novel process for conducting top-down SLA 3D printing from a thin resin layer located above a static immiscible supporting fluid, which reduces or eliminates the need for solid supports. The support fluid prevents deflection from buoyant and gravitational forces on thin overhangs from anchored parts due to minute density differences between the supporting fluid and cured resin, while reducing the volume of resin necessary to print compared to traditional top-down SLA. Using this process, we have experimentally demonstrated printed geometry with overhangs of up to 90 degrees. Additionally, necessary material properties of both fluids and process parameters of the system have been identified for the system’s feasibility and broader adaptation.