I may have been blinded by the number of war films and thrillers that I have already watched, but I consider helicopters as one of the important inventions that changed the game for defense, warfighting, transportation, and disaster relief missions. This has led many governments to go the extra mile to propel the helicopter industry. That’s the reason why, to be a consistent force to be reckoned with when it comes to defending a nation from the skies, helicopter manufacturers must also stay at the forefront of the technology. It takes a conversation with Frank Rethmann to understand what this journey looks like for Airbus Helicopters.
It’s probably the same for other manufacturing fields, but when you’re aware of the fact that helicopter manufacturers fall into two categories (those that can design, certify and manufacture new helicopter designs from scratch and those that can only manufacture extant designs under license), it is obvious to turn to a player of the first category to understand what an Additive Manufacturing journey looks like in this field.
As the world’s largest helicopter manufacturer, Airbus Helicopters surprisingly embarked on its path toward AM industrialization in 2017. This might be a bit late compared to other industrial companies of the same league in the broader aerospace field, but it remained a strong start. Unlike other aerospace OEMs who started way sooner and who made their first steps in plastics 3D printing, in 2017 the technology was mature enough to explore industrialization with metal 3D printing – which is what Airbus Helicopters did.
“We started our industrial application of AM in 2017 with the printing of shafts in titanium. In this first application, we took the existing design and reproduced the part using powder bed printing technology, achieving cost savings by improving the buy-to-fly ratio, meaning less titanium was needed to produce the part. Our strategy from the beginning was not just to establish the printing capability, but to master the entire end-to-end process chain, and we have achieved this. Since 2017, we have produced more than 13,500 shafts. Last year, we bundled our AM activities in our AM TechCenter in Donauwörth and significantly expanded our in-house capacity for this innovative process,” Frank Rethmann, Head of Industrial Service Center 3D Printing at Airbus Helicopters told 3D ADEPT Media from the outset.
The 3D printing center at Airbus Helicopters’ Donauwörth site integrates 3 industrial 3D printers for parts made of titanium, 5 3D printers for plastic parts, some desktop 3D printers and a recently added metal 3D printer that can produce parts made of aluminum. “The production area has doubled, with the latest expansion adding 500 square meters for Additive Manufacturing,” Rethmann notes.
At present, and according to Rethmann, the 3D printing center can produce both metal and composite 3D printed parts. With their thermoplastic 3D printers, they can produce non-structural parts like air conditioning for Airbus Helicopters. In addition to series production parts, the 3D printing center also uses their laser powder bed fusion (LPBF) 3D printers to contribute to research activities to optimize titanium 3D printing and develop aluminum-based applications.
“Our ALM facility also allows us to quickly adapt to new situations and to produce parts for our helicopter prototype applications, such as the recently unveiled Racer demonstrator, or for our CityAirbus NextGen.”
Although they do not use the same terminology as Pratt & Whitney (read the article on pp XX of this issue), Airbus Helicopters benefits from three advantages AM offers, its fellow manufacturer mentioned: part substitution/part adaptation, unitization and optimized design.
“Compared with the conventional version, we save about 45 percent in weight and 25 percent in costs by so far integrating ten parts into one component. Around 3,500 shafts have been produced and the first of these have already been installed,” I recall the Head of the Industrial Service Center 3D Printing department said during a presentation at Rapid.Tech 3D, an AM-dedicated event held in Erfurt.
On another note, “We also work in close collaboration with the other divisions of Airbus to co-develop ALM new technologies and materials,” Rethmann adds.
Challenges on the road: the case of the CityAirbus NextGen
The CityAirbus NextGen is an Airbus’ electric vertical takeoff and landing (eVTOL) prototype that falls into Airbus’ strategy to develop advanced air mobility services in countries around the world. Based on a lift and cruise concept, the prototype boasts an 80-km operational range and a cruise speed of 120 km/h – making it perfectly suited to a variety of flight operations.
In the aerospace field, there is only a short list of manufacturers – among which GKN Aerospace – who leverage AM to produce parts for eVTOL. As you may guess, the high-speed and long-range capabilities of some eVTOL designs make them suitable for rapid deployment of troops and equipment in remote or difficult-to-access locations hence their use in military applications such as transportation, and logistics.
For this reason, the team at Airbus Helicopters leverages the advantages of AM through new systems and new architectures. “Design for ALM will help us foster the benefits of using ALM for weight and cost savings, i.e. integrating ALM in the early design phase. It is also an opportunity to improve offerings by reducing production and logistics lead times,” Rethmann comments.
Among the new design elements that make for a robust and seamless architecture, and that could potentially require the use of AM, one counts the wings, the V-shaped tail as well as the eight electric-powered propellers that are part of the uniquely designed distributed propulsion system.
That being said, qualification and certification of safety-critical parts remain a big challenge on the road. While this is the case for many aerospace manufacturers, the team of Airbus Helicopters is lucky enough to be part of a broader corporation that has decades of experience in Additive Manufacturing.
“We are in close contact within Airbus and authorities to establish the routes to qualify and certify parts of increasing criticality where we believe the weight and cost savings compared to traditional manufacturing methods are very significant,” the Head of the Industrial 3D printing center notes.
At the manufacturing level, one solution that could be explored to address this challenge is digitalization. Needless to say the topic is broad and can be applied across various steps of the manufacturing chain but in this specific case, Airbus Helicopters that recognizes its importance, will explore this solution in the “process qualification and quality assurance process going forward.”
“Thanks to capturing data across the full process chain, we can use statistical process control to ensure the conformity of the parts”, Rethmann points out, speaking of these steps of the post-processing stage. Speaking of the manufacturing process itself, he adds: “Digitalization also enables us to further optimize the printing parameters , increasing our pricing capacity and reduce costs.”
Future outlooks
Airbus Helicopters has understood the 30:70 ratio principle. The biggest challenges that need to be addressed at the manufacturing level are in the downstream processing steps. But that’s not all.
With sustainability at the heart of manufacturers’ agenda, the OEM is aware of the advantages AM can deliver in this regard. As a matter of fact, Rethmann says AM allows them to not compromise their sustainability goals at the expense of cost or weight.
That being said, as per the words of our interviewee, by optimizing the buy-to-fly of the parts they produce, they use less raw material to make parts and consume much less energy compared to traditional forging and machining processes. However, the current focus remains to pursue “Design for ALM” (Additive Layer Manufacturing) to unlock the full potential of the technology for more and more applications, ensuring that they address the means to certify these applications.
“We must continue to work with powder material suppliers and machine manufacturers to further optimize the cost of parts. And we must continue our research into new materials and new applications. We believe that our ALM journey at Airbus Helicopters has been a great success so far and we look forward to the further business benefits this technology will bring in the future,” Rethmann concludes.
