Students Use Metal 3D Printing to Establish New Standards in Rocket Design

These parts and build plate are fresh out of a Velo3D Sapphire XC AM system. The components of the Reaper Turbopump fit on one 600 mm build plate of the XC system with room to spare. Such large format printers improve the manufacturing time and economics of 3D metal printing. Image courtesy of Velo3D

The aerospace industry continues to push metal additive manufacturing (AM) to convert innovative, physics-based designs into higher-performing components that are more dependable, affordable, scalable, and producible using the agile manufacturing technique. AM is not only in demand in the aircraft industry – it is a necessity. Two undergraduate students from Colorado University (CU) Boulder Aerospace Engineering Sciences program have worked with industry experts to develop a cost-effective and reliable rocket turbopump concept.

According to the case study, the main objective was to create a rocket component that could be produced in a single process. Not only would this reduce material and weight, but it would also significantly speed up production. Additionally, the avoidance of possible sources of failures inherent with conventional joining procedures is another benefit of this strategy.

In January 2021, while still in his junior year of undergraduate study, Zach Lesan, the team’s first leader, had the idea for the project. “I attacked the problem head-on,” said Lesan. “It was a huge opportunity to learn component design, complex assembly design, CAD, 3D-printing design principles, and a variety of software modelling solutions to first principles problems.”

In the fall of 2022, after Lesan had graduated and started an internship at SpaceX, his colleague Patrick Watson joined and took up most of the duties. Lesan met Watson at the CU Sounding Rocket Laboratory (CUSRL) while developing the turbopump. Lesan and Watson approached companies and asked for their knowledge and resources. Through these collaborations, the two students received access to cutting-edge technology and were able to test their concept.

Their objective was to rely less on traditional joining methods like brazing, casting, and machining, which hinder functional performance, reduce reliability, and draw from a shortening supply chain. “A lot of companies cast their parts,” said Watson. “The real big breakthrough in turbomachinery for space or energy is 3D metal printing, Laser Powder Bed Fusion (LBPF), mostly. We can now print the performance geometries we want, iterate the designs, get the surfaces we need, and use machining more selectively. Metal 3D printing makes our project possible,” he said. 

“We have gotten rid of so many potential traditional failure modes by minimizing part count,” said Lesan. “The issue then with AM is porosity and part verification. We can look at our build reports and see there were no errors in the process impacting quality.” 

Meanwhile, Watson stated, “There are some parts we had to buy or conventionally manufacture.”

“The purchased parts are fittings, bearings, seals, and fasteners to join flange sections. Otherwise, the focus was on creating a work-friendly, lower-cost system, that avoids traditional fit problems through combined parts,” he added.