Researchers at the University of Texas at Austin have developed a novel resin system for multicolor digital light processing (DLP) 3D printing that enables rapid fabrication of freestanding and non-assembly structures using dissolvable supports. The work, led by Zachariah A. Page and published in ACS Central Science, combines UV- and visible-light-responsive chemistries to produce materials with distinct solubility profiles, significantly streamlining post-processing.
Current DLP workflows are often limited by the need for manually removed support structures, especially when fabricating components with overhangs or internal joints. These limitations constrain automation and increase production time and cost. To overcome this, the team designed wavelength-selective photopolymer resins that form either an insoluble thermoset or a readily dissolvable thermoplastic, depending on the light color used during printing.
In practical terms, this allows supports to be printed in one material and rapidly dissolved using ethyl acetate, an environmentally friendly solvent, without affecting the primary structure. The supports dissolve in under 10 minutes at room temperature, eliminating the need for time-consuming sanding or cutting.
The research was supported by the U.S. Army Research Office, the National Science Foundation, and the Robert A. Welch Foundation. The authors also acknowledge collaboration with MonoPrinter and Lawrence Livermore National Laboratory.
High-resolution multimaterial printing
The research showcases how multicolor DLP can serve as a precise multimaterial platform, achieving sub-100 μm feature resolution with layer heights as low as 50 μm. By tuning the photoinitiator and photoacid systems to respond selectively to ultraviolet (365 nm), violet (405 nm), or blue (460 nm) light, the team spatially controlled polymer network formation in a single vat. This enabled the production of complex, freestanding structures such as chainmail, hooks with unsupported overhangs, and fully enclosed joints, which traditionally require extensive post-processing or multi-step assembly.
The supports, printed in a visible-light-cured thermoplastic, demonstrated sufficient mechanical integrity during the build, with tensile moduli around 160–200 MPa. Yet, upon immersion in ethyl acetate, they dissolved within 10 minutes, leaving the UV-cured thermoset structure intact. Surface profilometry confirmed that including a single interface layer of the dissolvable material between the support and the final object significantly improved surface finish, lowering roughness to under 5 μm without polishing. Computed tomography scans validated geometric fidelity, with dimensional deviations from CAD files as low as 126 μm, reinforcing the method’s capability for high-precision, solvent-cleared multimaterial printing.
Towards scalable automation
This work marks a significant step toward automated vat photopolymerization workflows. By removing manual support removal and achieving clean surface finishes with minimal roughness, the method could benefit applications in medical devices, robotics, and consumer products.
The authors suggest that future work may involve refining resin formulations to enhance performance and print speed, possibly incorporating new reactive diluents and opaquing agents for improved resolution.
Dissolvable materials as post-processing solutions
Dissolvable supports have been a focal point in additive manufacturing, particularly for enhancing the efficiency of post-processing. In Fused Deposition Modeling (FDM), materials like Stratasys’ SR-30 have been effectively removed using specialized cleaning agents such as Oryx Additive‘s SRC1, which dissolves supports at twice the speed of traditional solutions. For resin-based printing, systems like Xioneer‘s Vortex EZ employ heat and fluid agitation to streamline the removal of soluble supports . In metal additive manufacturing, innovations have led to the development of chemical processes that selectively dissolve support structures without compromising the integrity of the main part . These advancements underscore the industry’s commitment to reducing manual intervention and improving the overall efficiency of 3D printing workflows.
Read the full article in ACS Publications.
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Featured image shows: Hook geometry printed using multicolor DLP with dissolvable supports. Image via University of Texas at Austin.
