A rocket thruster demonstrator with integrated internal cooling channels was 3D printed at the end of 2022, using a newly developed copper alloy, GRCop-42, in a move that underscores additive manufacturing’s ability to accelerate innovation.
The demonstrator uses a regenerative cooling strategy to regulate the temperature by which the fuel of the rocket first flows through cooling channels to remove heat from the thruster’s walls before it is returned to the chamber for combustion.
Engineers used 3DXpert to develop the optimized printing parameters and build file prep for the demonstrator.
Evan Kuester, Ryan Fishel and Cameron Schmidt, engineers who created the demonstrator, used Autodesk’s Fusion 360 for the design, and Oqton’s 3DXpert to develop the optimized printing parameters and build file prep, including print orientation and support structures. Additionally, 3DXpert generated the slice data for the printer.
“The two most innovative aspects of this thruster are the material selected, a newly developed copper alloy, and that it was produced with 3D printing, which reduces the time, cost and effort required to manufacture, compared to conventional manufacturing methods,” Schmidt, who is Senior Application Development Engineer at 3D Systems, explains.
“In addition, the material used, GRCop-42 – a copper alloy recently developed by NASA – has traits that make it well-suited for high-temperature applications, such as rocket propulsion. Using it with laser powder bed fusion, we manufactured the thruster in a relatively short amount of time and achieved good density and mechanical properties,” he adds.
The demonstrator is a new addition to the stream of 3D printing rocketry applications which has been steadily growing in the last few years. Today a number of start-ups are developing 3D printers capable of creating components for rockets, and preparations for the launch of the first fully 3D-printed rocket, Terran 1, are currently in full swing.
While it is 3D-printed rockets that garner the most attention, they’re just the tip of the iceberg when it comes to additive manufacturing applications in aerospace and defense. Driving all these efforts is additive’s immense time-saving advantage which derives from the fact that manufacturers can make a single part in one go.
Fabricating a complex device with several components comes with many technical challenges. The components must be individually fabricated, brought together, and assembled in a process that is lengthy and tedious. 3D printing turns this on its head, making it much faster and cheaper to develop and fabricate the final product.
Rocket nozzles with regenerative cooling, like the demonstrator made with the new copper alloy, have been fabricated for decades using conventional manufacturing methods. While this size of rocket thruster would normally require several months to manufacture, the 3D-printed demonstrator was fabricated within just a few weeks.
The shorter lead times associated with additive manufacturing have monumental implications. For a start, rapid iteration has become financially viable, and subsequently, manufacturers can pick up the pace of innovation. Because it's faster to produce a part, an engineer using 3D printing can afford to experiment more and test various designs before settling on the optimal solution, without incurring excessive costs.
“With conventional manufacturing, engineers could fabricate a handful of different designs, but due to cost and long lead times, exploring many different designs would require too much effort and resources. With 3D printing you can try something and, if it doesn’t work or proves to be non-optimal, go back to the drawing board and iterate relatively quickly,” Schmidt explains.
In addition, with additive technology, companies can improve and optimize designs with the ability to fabricate geometries that would not be possible to manufacture with conventional methods. The cooling channels in this demonstrator are fully integrated into the walls and run through the length of the thruster, which can be routed in nearly any way imaginable that may further optimize heat transfer.
3D printing makes it possible to enhance the performance of components by applying techniques such as surface lattices and topology optimization of complex geometries, which would be difficult or impossible to make conventionally. These design principles are already being applied with amazing results in the manufacture of heat exchangers, medical implants and structural brackets.