ORNL Develops Novel Extrusion System for Single-Stream, Multi-Material 3D Printing

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.