researchers Oak Ridge National Laboratory ORNL, the U.S. Department of Energy’s largest multi-program science and energy laboratory, has developed a modular 3D printing extrusion system that increases throughput without increasing tooling weight. This system uses a specialized nozzle block to combine multiple small extruders into one material stream, allowing for output adjustment, precise deposition, and printing of multiple materials within one bead.

The research was conducted at ORNL’s manufacturing demonstration facility; Department of Energy‘s Critical Minerals and Energy Innovation Division receives additional support through its Advanced Materials and Manufacturing Technologies Division in collaboration with the SM2ART program. university of maine.

Throughput challenges for large extruders

Large extruders are heavy and require robust and often expensive gantry or robotic systems to move. Higher power levels can reduce accuracy for small volume tasks and cause material flow to become unstable. This can make printing small components or tapered designs more difficult, and lower speeds are often required to prevent heat buildup that can cause warping and print failure.

ORNL’s system provides an alternative by allowing small extruders to be turned on or off without affecting print quality. It also supports simultaneous printing of multiple materials within a single bead, reducing the need to replace equipment.

“This system is poised to redefine extrusion-based additive manufacturing by enabling smaller extruders to match the production output of larger systems, and by enabling unprecedented multi-material extrusion within the bead, without the added weight burden,” said ORNL researcher Halil Tekinalup, who led the project. “These advances will help strengthen the competitiveness of U.S. manufacturing and expand access to cutting-edge production technologies.”

Nozzle design for multi-material printing

The system uses a patent-pending aluminum bronze nozzle block designed for strength and thermal conductivity. Its internal structure combines two molten polymer streams from parallel extruders, allowing processing of a variety of large pellet feedstocks across multiple configurations. This design has been shown to consistently double the flow rate and potentially triple, quadruple, or more. Y-shaped nozzle reduces central pores and streamlines extrusion.

Researchers have also developed a nozzle that can produce core-and-sheath beads in which one material surrounds another. This allows materials with different mechanical or functional properties to be combined within a single bead. This design improves adhesion between layers and addresses delamination issues that can occur with polymer additive manufacturing.

Potential applications and test situations

The system has potential applications across multiple industries, as it can produce parts that combine different material properties in one part. In the aerospace field, it may be used in crash safety panels and radar absorption components. In the energy sector, applications include flame-retardant enclosures and modular battery supports. Defense applications range from lightweight shelters to protective panels, while civil engineering could include reinforced bridge decks and vehicle bumpers.

Testing to date has focused on large-scale pellet-fed polymer extrusion, showing improved throughput, consistent deposition, and multiple material controls. However, this system has not yet been evaluated for specific end-use materials, long-term durability, and certification in regulated industries. Its capabilities are limited to extrusion-based 3D printing and cannot address throughput challenges in other manufacturing processes.

Industry approaches to extrusion scaling

Throughput in extrusion-based additive manufacturing has traditionally been limited by tool weight, control, and deposition consistency, limiting real-world speed improvements. ORNL’s modular approach aligns with the industry’s continued efforts to develop flexible multi-extruder architectures.

in form next 2025, big rep Systems including the VIIO 250 operated at high temperatures, used dual smart manufacturing extruders (SMX) capable of processing engineering and reinforced materials, and demonstrated systems with features such as “Twin Mode.” Simultaneous dual extruder printing To improve throughput. It has also been reported from Formnext 2025, Prusa Research and bond tech The INDX Smart Toolhead is a dual extrusion feeder/tool ​​changer that can quickly change materials, supporting multi-material workflows without significant downtime.

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featured image show Modular multi-extruder system. Image via ORNL.