In the past five years, there has been a lot of column space given to how additive manufacturing (AM) might change the aerospace sector. The promise is there: time and again, AM has reduced costs and increased efficiency while shortening time to market, allowing for greater design flexibility.
So, why hasn’t AM taken hold of the aerospace market like all the gushing columns have led us to believe? AM has some significant hurdles to overcome before it can make the impact that it has promised in aerospace and defense (A&D).
Current AM useAM has been used in A&D in some form since the 1980s. As with other nascent technologies of that era, such as virtual reality, the capabilities have increased exponentially in the past few years, making AM more viable. And while there is plenty of room for expansion, aerospace is already spending $1 billion annually on 3D printing (A&D sector use currently accounts for 18% of total global revenues for AM). But in the context of the $2 trillion A&D industry, that spending equates to roughly a hill of beans.
AM is widely used in aerospace R&D for rapid prototyping, but commercial application results have been exciting yet inconsistent in quality and ambition. Applications have ranged from simple 3D-printed interior components, such as armrests, to GE’s Advanced Turboprop engine. While the benefits of these tests have been immense (GE’s turboprop engine combined 855 separate components into 12 and reduced the weight by 100 lb, improving fuel burn by up to 20% and giving it 10% more power), the attitude has been more about proving that we can and less about exploring realistic alternatives to traditional manufacturing methods.
Adoption challengesSeveral important factors have prevented AM from achieving widespread adoption in aerospace.
Inconsistent accuracy, quality – Safety is always the top priority in aerospace. For AM to be seriously considered, it will have to improve accuracy and replicability. The accuracy tolerance for most aerospace manufacturers is less than 10µm, while most metal AM machines can only produce 30µm to 40µm accuracy.
Production scaling – AM hasn’t reliably proven that it can ramp up to high volumes. Aircraft manufacturers must rely on their partners to meet the needs of high-volume, high-speed orders, especially when creating parts for a new aircraft program with a tight delivery timeline.
Size limitations – Planes require some of the largest components being manufactured. AM is great for small parts, but it is not yet competitive for larger components. The largest part created by AM (so far) is a Boeing 777X wing-trim tool. Roughly the size of a large SUV, the part was 17.5ft x 5.5ft x 1.5ft, weighing about 1,650 lb.
Industry standards – No consistent industry standards have been agreed upon. ASTM Int’l and ISO are currently working on standards for directed energy deposition (DED) AM. The National Institute for Aviation Research (NIAR) at Wichita State University, the country’s largest university aviation R&D institution, is working to create new technical standards for polymer 3D printing. And Boeing signed a 5-year collaboration agreement with Swiss technology and engineering group Oerlikon to develop standard processes and materials for titanium 3D printing.
Certification for commercial flight – One of the biggest challenges to overcome is getting 3D-printed parts certified for use on commercial aircraft. The more successful implementations there are, such as GE’s LEAP engine line, the more open the certification institutions are likely to be. And while it might be exciting to hear about a fully 3D-printed engine, starting with smaller, non-critical components is the best way to ease the industry into more AM usage.
Supply chain – The industry needs to figure out how AM fits into the aerospace supply chain, or how the current supply chain will need to shift to facilitate greater AM adoption. The supply chain of the future may not change much, simply offering a wider array of parts for smaller production runs. Conversely, AM could completely upend the existing supply chain, with original equipment manufacturers (OEMs); maintenance, repair, and overhaul (MRO); and even airline operators housing AM machines to print their own parts. Or it could be somewhere in the middle – a fully digital supply chain, with aerospace distributors providing CAD files so manufacturers can print their own parts.
A path forwardThe best path forward for AM is for the aerospace industry to determine where its strengths can complement those of traditional manufacturing. For high-production, traditional manufacturing will continue to be the best option (at least in the near term), while AM opens new avenues for highly customized, low-volume production runs to serve older planes, smaller aircraft programs, or business and private aircraft. The smart manufacturers will find room in their facilities and in their budgets to procure AM machines, allowing them to continue to serve their existing customers while they begin to explore new revenue streams. It also gives these manufacturers a leg up on learning the ins and outs of this technology, so they aren’t left behind when the capabilities catch up to the promise.