Greene County News
WRIGHT-PATTERSON AIR FORCE BASE – It’s a materials scientist’s dream, but as some experts say, an engineer’s nightmare. For scientists and engineers at the Air Force Research Laboratory’s Materials and Manufacturing Directorate, additive manufacturing, also known as 3-D printing, can be a powerful tool for rapid innovation.
Ultimately, it’s a new way of looking at manufacturing across the materials spectrum and an area with challenges and opportunities that the Air Force is meticulously exploring.
“Additive manufacturing is a huge opportunity for us,” said Dr. Jonathan Miller, a materials scientist and the additive manufacturing lead for the directorate. “It allows us to manufacture unique form factors; it provides the opportunity to add functionality and capability to structures that already exist. Essentially, it allows us to redefine manufacturing.”
Traditional manufacturing methods developed during the times of the Industrial Revolution, when machines began to overtake the human hand for mass production. Many of these processes required material to be molded or milled away from a larger form to produce a specific design.
Additive manufacturing, by contrast, is defined by ASTM International as the process of joining materials together, layer by layer, based on three-dimensional model data. It increases design possibilities, enhances the speed of innovation, and offers an alternative for creating shapes closer to what an engineer might need, with fewer constraints.
“The biggest problem with conventional manufacturing processes is time,” said Miller. “Manufacturing is an iterative process, and you never get a part ‘just right’ on the first try. You spend time creating the tools to manufacture a complex part and then spend more time when you realize an initial design needs to be modified. Additive manufacturing offers lower cost tooling and lower lead times. The early mistakes don’t hurt you as badly.”
Shift to Production Parts
While more affordable lasers and metal powder processes were helping scientists make better metal products, the ‘glue gun’ route to additive manufacturing of plastics became much cheaper. Small, inexpensive 3-D printing machines began to turn up in garages and schools, to the amateur engineers delight.
“Collectively, these became a new way of thinking about how to make stuff,” said Miller.
As additive manufacturing thinking evolved from being a way to develop prototypes to a method for actual production, the benefits and applications for the Air Force grew enormously, along with the potential for it to do even more. The manufacturing of customized parts and unique, complex geometric shapes at low production quantities can help maintain an aging aircraft fleet. Custom tools, engine components and light-weight parts can enable better maintenance and aircraft longevity.
“Additive manufacturing can address a multitude of challenges for us, and there is a big pull to implement these processes from the logistics community,” said Miller. “The fleet is aging, and replacement parts for planes built 30 years ago often no longer exist. Rapid production of a small number of hard-to-find parts is extremely valuable.”
However, the need to develop consistent, quality materials for additive manufacturing still remains a challenge that AFRL researchers are working diligently to address. Engineers need to have full confidence in additive manufactured part alternatives as they implement them as replacements in aging fleets or as system-level enablers in new weapon systems.
“There are limits as to how the Air Force can use this technology and for what applications it will work best,” said Miller. “That research is the basis of our work here.”
Additive Challenges and Future Potential
Despite years of development and research into additive manufacturing processes, there are a number of implementation challenges that AFRL researchers need to address in order to enable greater Air Force benefit from the technology, both now and in the future.
“Fundamentally, it comes down to a materials processing problem,” said Berrigan.
The lack of standardized production processes, quality assurance methods, significant material variability and reduced material performance are just some of the factors AFRL researchers need to overcome. Depending on the application, material performance can be related to the strength of a part. For example, the electronic properties of an additive manufactured circuit may be worse than those of ones traditionally manufactured.
“Understanding the safety, reliability and durability of a part is critical for an aircraft. We know this for parts made through other processes, but we don’t know this yet for additive,” said Berrigan.
Another issue centers on basic materials compatibility.
“There are a lot of different interfaces in additive manufacturing, and ensuring that materials adhere to one another or that a part can support a certain stress or withstand a certain temperature—these are all challenges we need to address,” said Miller.
The long-term goal, according to Berrigan, is for additive manufacturing to become a well-understood tool in an engineer’s toolbox, so that unique components can be design-integrated into a system. It’s difficult to go back in a system already built, he said, but additive manufacturing provides the opportunities to build-in greater potential at the start.
“The long-term vision is to have functional and structural additive manufacturing to work more cohesively from the start. Rethinking systems-level design to incorporate functionality such as electrical wiring, sensors or antennas is a potential that additive can help us address,” he said. “When you build something by layer, why not introduce channels for sensors, cooling or other functions?”
In all, AFRL researchers agree that continued research and time will lead to fuller implementation of additive processes for the Air Force systems of today and future. Innovative technologies are enabling capabilities, and additive technology is one with limitless opportunities to explore.
Story courtesy of the Air Force Research Laboratory of Wright-Patterson Air Force Base.