New 3D printing extrusion system redefines limits

Researchers at the Department of Energy’s Oak Ridge National Laboratory have developed a novel extrusion system that combines multiple 3D-printing extruders into a single, high-output stream via specially designed nozzles. This system matches the speed of larger extruders while providing greater flexibility, precision and multi-material printing capabilities.

Large extruders are heavy, requiring stronger and more costly gantries or robots to carry and move them. As their output increases, precision decreases in low-output applications, leading to inconsistent flow. This inconsistency poses challenges for printing both small parts and larger tapered designs, necessitating slower speeds to avoid heat buildup that could result in warping and print failure. ORNL’s adaptable solution allows users to add or deactivate smaller extruders without compromising quality. More importantly, the adaptable solution enables simultaneous printing of multiple materials within a single bead without the need to swap equipment.

“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.”

With its ability to print different materials quickly and precisely, this extrusion system can create parts that combine strength, flexibility and other distinct features in a single piece. That versatility makes it useful in many industries. In aerospace, it could be used to make crash-safe panels or radar-absorbing parts. In the energy sector, it could produce flame-resistant enclosures or lightweight modular housings and support structures for battery racks or thermal energy systems, enabling scalable designs that are critical for modernizing power infrastructure. Defense teams could use it to build strong, lightweight shelters or protective panels, while civil uses range from reinforced bridge decks, car bumpers and boat hulls — all in one continuous print.

The key to this solution is patent-pending nozzle blocks — made from aluminum bronze for strength and thermal conductivity — with an internal design that merges two molten polymer streams from parallel extruders. This design enables the system to process a diverse range of large-scale pellet feedstocks across multiple configurations, consistently doubling flow rates and 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.

In addition to the Y-nozzle, researchers have engineered a proprietary nozzle capable of generating core-and-sheath beads — where one material encases another — greatly enhancing the versatility of multi-material additive manufacturing. This development makes it possible to precisely combine two materials with differing mechanical and/or functional properties within a single bead. With these advancements, manufacturers can incorporate composite-cores with improved interlayer adhesion, solving the problem of delamination, or layer separation, which has been a major obstacle in polymer additive manufacturing.

“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.

Additional ORNL researchers who contributed to this project include Alex Roschli, Jesse Heineman, Soydan Ozcan, Brian Post, Paritosh Mhatre, Umesh Marathe and Ercan Cakmak.

The project was funded by DOE’s Office of Critical Minerals and Energy Innovation, Advanced Materials and Manufacturing Technologies Office (AMMTO). Research for this project was sponsored by DOE as part of the SM2ART Program with the University of Maine.

The Manufacturing Demonstration Facility, where this work was conducted, is supported by AMMTO and acts as a nationwide consortium of collaborators focused on innovating, inspiring and catalyzing the transformation of U.S. manufacturing.

UT-Battelle manages ORNL for the DOE’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. The Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science. — Tina M. Johnson