Additive manufacturing is one of the key elements of the Industry 4.0 technology and process toolbox, and as it evolves beyond custom 3D printing to become a major part of the aviation industrial process, we sat down with industry experts at Airbus and Honeywell for the latest of our ab initio introductory guide series.
Often referred to as simply AM, a concise way to start thinking about additive manufacturing as a process is to liken its early implementations to an industrialised version of the 3D plastic printers that are now common in many manufacturing situations — and even for hobbyists from home DIYers to cyclists to miniature wargamers.
Hauke Schultz, Airbus’ additive manufacturing roadmap leader, tells us that, “in contrast to subtractive manufacturing technologies like machining, AM adds material layer by layer to build up parts. Further in contrast to forming technologies, it does not need part specific toolings. This makes AM very suitable for complex and highly optimised parts in relatively low quantities. Over the last decade or so, AM technologies and materials were industrialised that are interesting for aerospace like high performance thermoplastics but also alloys like titanium, Inconel [a series of nickel-chromium-based superalloys] and high-strength aluminium.”
Indeed, Airbus’ civil aviation business has been using early additive manufacturing methods like stereolithography, a type of 3D printing using plastics, since the late 1990s, first to create wind tunnel models.
Use cases then scaled to serial parts on helicopters as well as using selective laser sintering — essentially, heating a powdered material using a laser to fuse it into a three-dimensional shape — for low-volume, high-change applications such as assembly tooling and during the flight test process.
“At Airbus we have successfully certified and implemented both polymer and metal additive manufacturing for serial production parts. However, AM is a relatively complex and still expensive manufacturing technology,” Schultz says. “It has not yet scaled as much as expected some 5-10 years ago. But the trend goes in the right direction with machines getting larger and more productive. Similarly, Airbus Tier 1 part suppliers, who use AM machines, are becoming more experienced. Therefore we still expect additive manufacturing to grow in relevance and value for Airbus, especially for new product development.”
In the late 2010s, Airbus began producing both polymer and metal parts for both its A350 and A330neo widebodies, and continues to research other applications.
“Airbus works widely with academic and technology partners for initial development and implementation of AM technologies,” Schultz explains. “We have internal capabilities to make sure we understand new technologies and we can ensure a safe qualification and certification. When scaling up mature AM technologies, we work with our strategic part suppliers.”
AM within the supply chain offers many potential advantages
Within that supply chain, additive manufacturing is reducing cost, adding flexibility and improving logistics, as Yeong-chuan Lim, Honeywell country president for Malaysia and Singapore, tells us.
Honeywell is “harnessing additive manufacturing for components such as aircraft auxiliary power units and generators — ensuring the entire bill of materials for every product and part is on the assembly line in time,” Lim says. “Additive manufacturing enables us to store raw materials rather than SKUs on site, making it possible for us to print parts on demand and manufacture with less cycle time, thus increasing manufacturing efficiency.”
Incorporating the supply chain into the aircraft, Airbus’ technology roadmap includes five key combinations of materials and processes:
- titanium via directed energy deposition
- titanium via powder bed fusion
- aluminium via powder bed fusion
- polymers
- composites
“There is a lot of dynamism in the AM industry,” Schultz says. “We do not limit ourselves to single technology providers [nor] geographic regions. A lot of AM technologies are rooted in Europe but we see a lot of scaling and development in North America (or USA) and Asia (or China). It is in our interest as a global enterprise to be active in these areas.”
Legacy, current and future aircraft programmes can all benefit from AM
Evolving drivers and use cases for additive manufacturing helpfully support each other in a virtuous cycle. Legacy aircraft programmes see lower demand volume as aircraft age, while manufacturing technology may be four decades old, meaning that AM is ideally placed.
For current programmes, tranche-based improvements and optimisations — often referred to as performance improvement packages, or PIPs — drive systems simplification, weight saving, aircraft performance gains and the use of new materials, and AM can contribute helpfully to all of these.
The complexity of pieces manufactured via additive technologies will increase in the long term, and indeed as AM matures the industry can use the benefits of the process — and new technologies that emerge — at the design stage.
“With regard to our legacy systems, it is indeed more difficult to make use of the strength of AM on an existing product,” Schultz notes. “On the other hand, those programs allow us to gain experience with selected parts and push the competitiveness of the technology before using it on new programs.”
Scaling additive manufacturing is a serious question, and requires a substantial amount of confidence building work within the supply chain, with airworthiness authorities, and indeed with customers. The growing use of AM for flight-critical parts is a key step along this path.
Looking towards the future, Schultz says, “in the area of polymers we work on direct extrusion technologies which use industry standard raw materials that are much cheaper and more compatible with our ambition to implement circular material flows. On metal AM we see a lot of scaling and towards AM factories. We also see new laser technologies like beam shaping that could enable much higher productivity.”
New alloys are emerging for use in additive manufacturing, especially around the industry’s research into hydrogen aircraft, where the requirements for very low temperatures around liquid hydrogen are particularly stringent. Further benefits will include a substantially greater amount of flexibility from design to industrialisation stage, through prototyping, development, testing and initial production.
Author: John Walton
Published: 17th October 2024
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