Researchers at Lawrence Livermore National Laboratory (LLNL) have developed a novel dual-wavelength 3D printing technique that enables the clean removal of support structures, potentially overcoming one of the key challenges in additive manufacturing.
The new method, detailed in a recent study published in ACS Central Science, uses light of two different wavelengths to simultaneously build complex 3D structures and generate temporary support material from a single resin.
The supports can then be cleanly dissolved in a water-based solution, eliminating the need for manual removal and reducing the risk of damaging the final product.
LLNL researchers collaborated with the University of California, Santa Barbara (UCSB) on the project. The team’s approach centres on a custom-built dual-wavelength negative imaging (DWNI) printer, patented by LLNL engineer Bryan Moran.
The printer projects both ultraviolet (UV) and visible light at once, with each triggering distinct chemical reactions. The UV light cures the final epoxy structure, while the visible light cures a degradable thermoset designed to dissolve after fabrication.
“This work adds another option to the growing range of multi-material printing possibilities,” said principal investigator and LLNL staff researcher Maxim Shusteff.
“Using multiple materials is critical to many manufacturing processes, and that’s been hard to accomplish using 3D printing. And manually removing supports printed from the same material is one of the bottlenecks preventing the use of DLP in production activities and hurting part accuracy.”
After postprocessing, printed parts are placed in a basic solution where the supports dissolve, leaving the final structure undamaged.
The researchers demonstrated the method using complex free-floating designs such as interlocked rings and a ball-in-a-cage, forms that are difficult to fabricate using conventional techniques.
According to first author Isabel Arias Ponce, a UC National Laboratory Fees Graduate Scholar and incoming LLNL materials engineer, the one-pot process can improve the fidelity of unsupported elements like overhangs and cantilevers, and even allow for in-place fabrication of movable components by patterning degradable interfaces.
“Additionally, mobile components — such as hinges and interlocking systems — could be fabricated in place by simply patterning a degradable interface between multiple parts,” Ponce said. “This would eliminate the need for manual assembly and enhance production efficiency.”
The project was supported by the Laboratory Directed Research and Development program and the Lawrence Postdoctoral Fellowship at LLNL.
Co-authors of the study include former LLNL postdoctoral fellow Sijia Huang, now an assistant professor at the University of Utah, and UCSB’s Professor Craig Hawker.
