The U.S. is in the midst of a hypersonics arms race. Craft traveling five times or more the speed of sound in a guided way could change warfare. In a few hours, a surveillance platform or payload could be put over anywhere on earth. Hypersonic glide vehicles could outrun enemy defensive radar and response. Larger hypersonic missiles would have global reach without the need to travel in great arcs over the horizon. Without giving the enemy any heads up, these weapons could change the nature of a first strike and the concept of intercontinental ballistic missiles. Hypersonics are the new high ground.
Key to enabling the technology are the optimization and weight saving structures needed for extremely high performance shapes and materials. That’s where 3D printing comes in.
We’ve seen NASA make new oxygen dispersion strengthened (ODS) alloys for hypersonics, as well as cases in which the U.S. working with Australia and the UK on hypersonics. There’s been research at Purdue University and the Air Force, too. So far, all the public work has focused around superalloys, intermetallics, ODS alloys, and other extremely high-temperature metals. Metals and ceramics are the only materials that can subsist under the extreme forces and heat of hypersonic travel. However, Northrop Grumman has revealed that 3D printing of polymers may play a role as well.
Northrop has developed what it is calling Scalable Composite Robotic Additive Manufacturing Carbon/Carbon (SCRAM C/C), a patented process that relies on a robot arm featuring a combination of material extrusion and automatic fiber placement (AFP) to create carbon fiber structures with high-temperature materials. Northrop has been working on 3D printing for a long time with layered object manufacturing (LOM) patents going back to 2000 or so and a stereolithography die process from around the same time. It also has a method to repair carbon fiber components, as well. It even has a patent on how to manufacture a golf club head with insert.
SCRAM and other similar technologies, such as that from Impossible Objects, can make very strong structures that are resistant to higher temperatures than other polymers. The part above is an inlet duct, made with a version of SCRAM C/C that was first mentioned in 2022. The technology was likely in use earlier and has been used for parts on the joint strike fighter and other aircraft. The company touts a 50% labor cost saving, as a significant advantage, but also suggests that quality can be increased. Check out the video below to see some Raise3D printers at Northrop alongside the SCRAM C/C process.
What’s new is that now Northrop is framing SCRAM C/C as a way to achieve “hypersonic supremacy,” via weight savings and performance improvement, as well as faster production times.
“We’ve manufactured a part that started with a circular cross section, swept through an S shape and ended in a rectangular cross section. That’s an extremely complex geometry that in the past was only possible to create by hand and could take up to a year to make. Now we can make it in a few weeks,” said Tim Dominick, a Technical Fellow at Northrop.
“The race to take hypersonics from the research and development lab bench to practical reality over the next few years is one of the greatest technical challenges for the U.S., and it is one we must win to protect the long-term security of the nation. Our work using SCRAM C/C is an exciting example of different teams coming together to tackle this challenge, using commercial innovations like robotics, additive manufacturing, material science and digital engineering to accelerate our progress,” contributed Jeff Yu, Northrop’s corporate director of technology.
It is notable that Northrop is going for its own technology, bypassing vendors in the field. Also, one gets the distinct impression that the whole hypersonics arms race is going to cause an ungodly amount of money to rain down on defense companies.We will see a lot of investment and work spill over from hypersonics and the military. The race to develop high-end service bureaus in the vein of Sintavia and BEAMIT is underway to cater to this demand. At the same time, the defense community is sure to buy a lot of very large and very productive machines in the years to come. We do risk militarizing 3D printing and becoming a very defense adjacent technology in the process.