We’ve been talking a lot about multi-material printing lately, and for good reason. The technology is advancing rapidly on both the maker and professional sides, from Bambu Lab’s and Prusa’s latest multi-material desktop systems to more experimental approaches. Now, researchers from the Oak Ridge National Laboratory have unveiled a novel, multi-material 3D printing system. The structure involves multiple extruders combined into a single, high-output stream via a specialized nozzle. According to ORNL, the system matches the speed of larger extruders while providing more flexibility and precision.
The project was developed out of the need to improve large extruder performance. First, large extruders are heavy, which means they need stronger and more expensive gantries or robots to carry them. When output increases, precision can decrease, causing flow inconsistencies. This causes problems for small parts and large tapered designs. To accommodate this, the printing speed has to slow down, which prevents heat buildup that can cause warping. ORNL is presenting a more efficient solution: it allows users to add or deactivate smaller extruders without compromising quality. Critically, it allows for the simultaneous printing of multiple materials within a single bead without the need to swap equipment.
The method allows for multiple materials to be deposited in a single bead.
How Does It Work?
ORNL’s design hinges on patent-pending nozzle blocks. Made from aluminum bronze for strength and conductivity, these blocks have an internal design that merges two molten polymer streams from parallel extruders. This design lets the system process a wide range of large-scale pellet feedstocks across multiple configurations. Remarkably, ORNL reports that it consistently doubles flow rates, showing promise to triple, quadruple and so on. The multiplexing system streamlines the extrusion process and significantly reduces center porosity through the implementation of a Y-shaped nozzle.
“By enabling smaller-scale extruders to match the output of larger systems without the burden of extra weight — and by achieving unprecedented multi-material extrusion within the bead — this system is poised to redefine extrusion-based additive manufacturing,” said ORNL researcher Halil Tekinalp, who led the project. “These advancements will help strengthen U.S. manufacturing competitiveness and expand access to cutting-edge production technologies.”
Besides the Y-shaped nozzle, the researchers also engineered a proprietary nozzle that can generate core-and-sheath beads (where one material encases another). This development enables two materials to be precisely combined, allowing for different mechanical and/or functional properties within a single bead. Manufacturers can therefore incorporate composite-cores with improved interlayer adhesion, solving the problem of delamination, or layer separation, which has been a significant challenge in polymer AM.
Potential Applications
This technology could be used for a variety of applications. It could fabricate crash-safe panels or radar-absorbing parts for aerospace, or strong, lightweight shelters or protective panels for defense. For the energy sector, the method could create flame-resistant enclosures or lightweight modular housing and support structures for battery racks or thermal energy systems. There are civil project applications, too, like reinforced bridge decks, car bumpers, and boat hulls.
“This innovation opens up new manufacturing horizons, making it possible to achieve complex, efficient and creative designs with dynamic material switching, all while preventing cross contamination — meaning the distinct materials remain pure and do not mix unintentionally,” said Vipin Kumar, another technical lead on the project. To learn more, read the article from ORNL here.
What do you think of this multi-material 3D printing method? Let us know in a comment below or on our LinkedIn or Facebook pages! Plus, don’t forget to sign up for our free weekly Newsletter to get the latest 3D printing news straight to your inbox. You can also find all our videos on our YouTube channel.
*All Photo Credits: Halil Tekinalp/ORNL, U.S. Dept. of Energy