In the realm of aerospace technology, the race to develop propulsion systems capable of powering vehicles at hypersonic speeds has never been more intense. Hypersonic flight, defined as speeds above Mach 5, is now within our grasp, thanks in no small part to the fusion of 3D printing and cutting-edge materials.
In this blog, we delve into a captivating case study where Velo3D, Lockheed Martin, and Vibrant teamed up with the Department of Defense’s LIFT Institute to pioneer a data-driven approach for certifying materials and methods crucial to additively manufactured aerospace systems.
From the inception of the project to the intricate details of materials science, this remarkable partnership is paving the way for a new era of aerospace engineering.
The Urgency of Hypersonic Flight
The demand for advancements in aerospace applications, particularly in the defense industry, has reached an all-time high. Global competitors are striving to develop propulsion systems that can power aerosystems at supersonic and hypersonic speeds, ushering in a new era of aerospace technology. This endeavor has opened the door to innovative manufacturing methods.
At the forefront of this technological revolution is 3D printing.
3D Printing: Transforming Aerospace Manufacturing
3D printing has emerged as a transformative technology in aerospace manufacturing. It offers the ability to create intricate, single-piece engine designs that are not only lighter but also quicker to produce compared to traditional manufacturing methods.
Additionally, materials development is evolving in tandem with 3D printing, with a focus on certifying high-performance metal alloys specifically tailored for additive manufacturing (AM) systems.
The Role of the U.S. Department of Defense
While prototyping remains essential in achieving aerospace goals, the U.S. Department of Defense (DoD) has embarked on a comprehensive approach to AM, starting with a deep dive into materials science and manufacturing.
In this pursuit, the DoD has partnered with LIFT, a nonprofit public-private collaboration situated in Detroit, Michigan. LIFT operates as a key player in the American Lightweight Materials Manufacturing Innovation Institute, and it is at the forefront of advancing technology from research to commercialization.
LIFT: A Beacon of Innovation
LIFT stands as an exemplary model of public-private partnership, bridging the interests of the DoD, industry, and academia. Operating within a vast 100,000-square-foot facility, LIFT is dedicated to scaling emerging technologies into commercial applications. Among its myriad projects, the “Hypersonics Challenge,” funded by the DoD’s Manufacturing Technology Program, holds a prominent place. The challenge’s objective is to pinpoint materials and manufacturing processes that can efficiently lead to hypersonic flight-capable vehicles and missiles.
LIFT’s Engineering Director, Dr. John Keogh, plays a pivotal role in this endeavor, along with Dr. Amberlee Haselhuhn, Director for Materials & ICME.
John Keogh, technical lead, and project manager Brad Friend hold a cut section of the LIFT Hypersonic Challenge 3D-printed ramjet. The project was centered at the American Lightweight Materials Manufacturing Innovation Institute’s 100,000-square-foot facility in Detroit, Michigan. Image courtesy LIFT.
3D Printing Takes Flight: The Ramjet Project
In a groundbreaking effort, LIFT, Lockheed Martin, and Vibrant joined forces to embark on a journey to create a 3D-printed ramjet engine. The project’s primary goal was to ascertain what data could be gathered during the laser powder bed fusion (LPBF) printing process and how that data could be utilized to certify components for hypersonic flight. This approach marked a departure from traditional statistical methods of part validation, focusing instead on real-time data streams for certification.
The LPBF system chosen for the ramjet project was the Velo3D Sapphire 1 MZ, renowned for its ability to print objects up to one meter in height.
This video shows 15,247 layers of Inconel® 718, printed on a Velo3D Sapphire 1MZ printer in just 26 seconds as a solid piece without supports, and designed for small aircraft flying at supersonic speeds.
Each Sapphire system is equipped with hundreds of sensors, providing comprehensive real-time data during the printing process. Velo3D’s technology not only collects vast amounts of data but also boasts an impressive build envelope, ideally suited for volume manufacturing.
From Classroom Assignment to Aerospace Breakthrough
The origin of the ramjet design is a testament to the innovative spirit that drives aerospace engineering. Conceived as a classroom assignment by an undergraduate aerospace engineering student at Purdue University, the ramjet design aimed to consolidate complex engine components into a single 3D-printed structure.
Jay Blake’s design envisioned incorporating the inlet spike of a ramjet into a turbojet, acting as a heat exchanger to enhance fuel combustion efficiency. His homework project was inspired by the J-58 turbojet used on the SR-71 Blackbird (which, as of September 2023, still holds a 1976 record as the fastest—Mach 3.2—supersonic air-breathing manned aircraft). Years later, this design resurfaced when Blake began working for Velo3D, leading to the realization that his vision could become a reality.
Creator meets creation: former engineering student Jay Blake, now on the aerospace applications team at Velo3D, cleaning the ramjet after 3D printing. He came up with its original design as part of an undergraduate course assignment. Image courtesy Velo3D
Lockheed Martin’s Interest and Adaptation
Lockheed Martin, a prominent aerospace manufacturer and Velo3D customer, took a keen interest in the 3D-printed ramjet project.
North Star Imaging’s innovative technology helps validate internal geometries in a part without destroying that part. Their 3D Computed Tomography (CT) X-ray inspection services use the most advanced X-ray inspection technology to provide the clearest picture of a part, inside and out, virtually eliminating any evaluation errors. The scans shown here are solid surface, slice and internal surface.
Lockheed Martin worked in partnership with Velo3D and LIFT to aid the team’s research into the development stage of metal AM for specific uses, along with the accuracy of the materials employed for this purpose. Blake’s design, free from ITAR-controlled geometry, served as an ideal example for AM. This allowed for comprehensive evaluation of the metallurgy, structure, and 3D printing process without the constraints of ITAR and export control.
While the initial design was intended for supersonic engines, Lockheed Martin recognized the potential for adaptation into a scramjet engine, capable of achieving hypersonic speeds. This collaboration set the stage for evaluating the maturity of metal AM for mission-critical applications and scrutinizing material fidelity.
Quality Assurance through Resonance Testing
To assess the quality and integrity of the 3D-printed ramjet components, the team employed Process-Compensated Resonance Testing (PCRT) by Vibrant. PCRT uses ultrasonic frequencies to excite the vibrational modes of a part, recording unique resonance frequencies based on geometry and material properties. This non-destructive approach proved effective in identifying internal cracks, porosity, and surface defects, offering valuable insights into component quality.
Data-Driven Certification and Future Prospects
The success of the ramjet project heralds a new era in additive manufacturing certification. The data collected during the printing process serves as an objective representation of part quality, paving the way for predictive models that link post-build data with data streams.
Machine learning and data-fusion techniques are expected to play a pivotal role in discerning indications of quality, enabling more efficient certification processes. As the project enters its next phase, fatigue behavior will be a key focus, with the ultimate goal of producing “born-certified” hypersonic components.
A Pathway to “Born-Certified” Hypersonic Components
The collaboration between Velo3D, Lockheed Martin, and Vibrant at the LIFT Institute stands as a beacon of innovation in aerospace engineering. By harnessing the power of 3D printing, data-driven certification, and cutting-edge materials, this partnership is advancing the boundaries of what’s possible in hypersonic flight.
As we look ahead, the prospect of “born-certified” components and the continued involvement of undergraduate talent signal a bright future for aerospace technology.
With the sky as the limit, we can expect even greater breakthroughs on the horizon.
