In the fall of 2023, Boeing announced it would begin testing 3D-printed components of a main rotor system for its Apache attack helicopter. While some industries have struggled to balance the cost-benefit equation for additive, aerospace has always been a natural fit for the technology.
Engineers in this space have long grappled with weight-to-fly ratios, and the need for complex, lightweight, and high-performing parts and materials has made the sector a pioneer in developing additive technologies.
Boeing's main rotor system project is one of an increasing number of use cases where additive manufacturing (AM) is enabling manufacturers to cut lead times, eliminate supply chain bottlenecks, and fabricate stronger, more efficient components. Within aerospace and defense, industrial 3D printing can solve problems that no other process can.
Fueling Progress
One of the earliest mass applications of this technology in aerospace was for the LEAP engine fuel nozzle. In the late 2000s, CFM International, a collaboration between GE Aviation and Safran Aircraft Engines, was working on a new commercial jet engine.
The LEAP engine's design relied on its intricate fuel nozzle, which featured 14 separate fluid passages. The team focused on the initiative quickly realized that the interior geometry of the part was too complicated to make through casting. This led them to re-engineer a 3D printer to produce it, transforming it from a 20-piece welded composite to a single component. In doing so, they reduced its weight by 25% while increasing its durability and cost-efficiency.
GE Aviation went on to open a 3D-printing site in Auburn, Alabama, where the fuel nozzle would be produced — the industry's first facility for AM-powered mass production. As the first 3D-printed component used in a jet engine, the LEAP engine fuel nozzle triggered a surge in AM adoption, spurring investment from peers and competitors on the market.
Complexity, Speed, and Fleet Sustainment
People often tout the claim that in AM, "complexity is free." By this, they mean users can create complex geometries at no additional cost. That's not necessarily true. In fact, printing complex geometries can add to the cost of production by extending design and build time and augmenting material consumption.
That said, AM does allow manufacturers to print intricate parts that cannot be produced in any other way. In addition, the materials and products developed through AM are increasingly achieving superior levels of tensile strength, fatigue resistance, and fracture toughness when compared with those made using traditional forging and casting methods.
Boeing was able to pursue its main rotor system project thanks to additive friction stir deposition (AFSD), a practice that combines elements of friction stir welding and AM. A process whereby the material never melts but instead softens from the heat of friction.
The company has already produced the project's first output — a main rotor link assembly — printed using the world's largest 3D metal printer at Rock Island Arsenal in Illinois. Using 3D printing, the component was produced in under nine hours. In contrast, the part would have incurred a lead time of around a year using the traditional forging technique, according to an expert on the project.
Reduced lead times are not the only advantage that AM offers for fleet sustainment. In cases of material or process obsolescence, industrial 3D printing can enable manufacturers to create parts that are no longer available via traditional means. Printing a replacement component rather than relying on conventional methods to make a repair could mean the difference between an aircraft being grounded for days or out of service for months — or even years.
Eyeing the Horizon
While some may still consider AM a relatively new process, there has been a notable shift in perception within aerospace over the past five years. Today, engineers and designers have the benefit of years of data and use cases to draw from — even as novel applications, materials, and processes are being developed.
Events like RAPID + TCT help to disseminate new ideas, data, and research, allowing for a more comprehensive understanding and adoption of AM technologies. With over 400 exhibitors on the show floor and dedicated conference tracks for both aerospace and defense, attendees can gain in-depth insight into the research and development fueling the industry's progress.
From lightweight composites to industry-wide specifications and standards, there are numerous possible avenues for the further advancement of AM in aerospace and defense manufacturing. Judging by AM's evolution thus far, we're only scratching the surface of what this technology can achieve.
As innovation continues to accelerate, AM has enormous potential for the aerospace and defense sectors. As North America's largest AM and industrial 3D printing event, RAPID + TCT is the ideal launchpad for the industry's next stage of growth.
This article was written with input from Theodore Anderson and Daniel Braley, who serve as event advisors for RAPID + TCT 2024.