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3D printing takes off

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Additive manufacturing, Aerospace

Why the aerospace industry is betting big on 3D printing otherwise known as additive manufacturing.
BY TEAM MT

3D printers have been used to make everything from pizzas to prosthetic hands to guns. Now, with aerospace parts another item can be checked off of that list. Aerospace giants think this technology is poised to revolutionise the way expensive, high-maintenance products are manufactured. “Absolutely! Seeing the response we have received from our key aerospace customers I don’t doubt that statement,” said an excited Anand Prakasam, country manager, India, EOS. “Evaluating the readiness for Additive Manufacturing (AM) the aerospace industry is definitely in the lead. In fact, this industry is embracing AM not just for rapid prototyping but actually for serial applications.”
Lockheed Martin, Boeing and other aerospace companies have already embraced the concept of using 3D printers to manufacture small parts. For example, Lockheed’s Juno spacecraft, which is on its way to explore Jupiter, relies on a set of 3D printed brackets. Boeing has used several 3D printed parts in its airplanes, including the Dreamliner.
Today, GE is ramping up the manufacturing of aero engine fuel nozzles.
“By 2015/16 GE aims to produce 10-20 nozzles for each engine using AM. They envisage that 50% of jet engines will be additive manufactured within current life times,” informed Sanjay Sangam, head, Renishaw India. This engine, called LEAP, will not enter service until 2016 on the Airbus A320neo. However, it has already become GE Aviation’s bestselling engine. No surprises there – considering that it is the world’s first passenger jet engine with 3D printed fuel nozzles and next-generation materials, including heat-resistant Ceramic Matrix Composites (CMCs) and breakthrough carbon fibre fan blades woven in all three dimensions at once.
In India some private sector organisations have already started investing in AM and working on producing aircraft parts in Titanium and Inconnel. For example, Nickunj Eximp Entp are the technology partners for Concept Laser GmbH in India. Also, players like GTRE and HAL are using this technology either directly or indirectly. “At present the application is still in prototype stage but then this is the way how in other markets the aerospace companies have evolved as well. In general the acceptance is positive. The technology has lots of potential for improvement in terms of new material development, introducing new features on the machine, automation, higher power laser, build size, etc. and reputed machine manufacturers are working on this,” affirmed Sangam.

Additively manufactured parts will always have to compete with parts produced conventionally, i.e. they have to achieve the same part properties, ideally exceeding those of parts traditionally manufactured. Agreeing, Prakasam added, “Zeroing on this technology means that you have to design for AM which is a completely different approach compared to conventional design and manufacturing. It still needs a lot of education on the customer side and they have to go through a longer learning curve.”
To make the most of the potential of AM techniques, designers have to move away from the idea of replicating what is already made in other ways. “Designers are free to move away from creating things that can be CNC machined and should not be constrained by the idea that things have to be built up in layers. Today’s CAD programs are considered inadequate for designing for AM. CAD is still designed for traditional manufacturing routes such as injection moulding, and in particular CAD is most readily applied to things which have lots of circles and straight lines,” opined Sangam.
Laser melting with metals has gained importance in aircraft manufacturing: quicker throughput times, more cost-effective components and hitherto
unimaginable freedom of design are often-cited advantages of this technology. However, a range of new benefits are now becoming apparent, such as lightweight construction, bionics and a new approach to design. A bracket connector used in the Airbus A350 XWB was honoured as a finalist in the running for the “2014 German Industry Innovation Award.”
Talking of AM vis-à-vis traditional manufacturing, Peter Sander, head, emerging technologies and concepts, Airbus (Hamburg) said, “Our primary objective is to reduce weight. This approach helps our customers, the airlines, operate their aircraft more economically. Additive layer manufacturing or laser melting with metals, also known simply as 3D printing, allows us to design completely new structures. They are actually more than 30% lighter than conventional designs realised using casting or
milling processes.”
Also they can directly proceed from 3D designs to the printer. Usually tools are required to manufacture aircraft parts – this is now no longer the case. This saves money and shortens the time until the component is available for use by up to 75%. A case in point being previously Airbus had budgeted around six months to develop a component – now, it’s down to one month. “The high degree of geometrical freedom of design enables more effective lightweight construction solutions compared to conventional approaches. For the brackets we’re currently focusing on, this means a considerable weight reduction, which in turn translates into lower fuel consumption and the potential to increase the load capacity of aircraft. These represent important steps toward more sustainable solutions,” asserted Claus Emmelmann, CEO, Laser Zentrum Nord GmbH.
Sander also mentioned that milling of aircraft parts in particular results in up to 95% recyclable waste. “With laser melting, we produce components with ‘near-final contours’, which are associated with waste of only around 5%. This makes the process especially attractive when valuable and expensive aircraft materials, such as titanium, are being used. Compared to casting, we have the additional advantage of not requiring any foundry tools. This is tangibly reflected in saved time and improved cost structures. Furthermore, additional safety considerations are associated with cast parts, such as cavities. Last but not least, they are heavier than printed components.”
In addition to reduced resource consumption, the ability to economically keep component density under control and determine the microstructure quality are additional aspects. Seconding, Frank Herzog, CEO, Concept Laser GmbH (Lichtenfels) stated, “Another fundamental quality feature is the ability to define the force distribution within the component, which is often impossible with conventional parts or is considerably more difficult to achieve. This is an important argument when it comes to safety-related components. Reduced energy and resource consumption are features of the laser melting process. LaserCUSING is a green technology and improves the often discussed environmental footprint of production.”

The aerospace industry is a key growth market for additive manufacturing. Not only brackets but also engine, turbine parts as well as cabin interior components are typical applications for AM. “This is where the benefits of the EOS technology comes to the fore: functional components with complex geometries and defined aerodynamic properties can be manufactured quickly and cost-effectively. Material and weight savings provide lower fuel consumption and CO2 emissions. Manufacturer-specific adaptations and small production runs are further arguments in favour of the AM technology. This is why leading aerospace companies have integrated AM into their planning of future production strategies,” affirmed Prakasam.
Since, AM is comparatively a new technology it experiences the same cycles like every other newly introduced technology. “AM as a technology comes first, then standards etc. will follow. Our big OEM customers like GE, MTU or Boeing are already working on testing methodologies and standards that enable them to introduce parts manufactured with AM to actual use. We are working on this too. For example, we are developing monitoring tools that will enable a new approach of in-process quality assurance. Yet, it will still take some more years before an industry as regulated as aerospace will see a perfect and stringent setup of standardised testing,” informed Prakasam.
Presenting his views, Sanders professed, “Generally speaking, there are no compromises in aircraft construction, since safety is the prime concern. Especially when one considers that our products remain in the skies for up to 30 years. When it comes to metals in aircraft construction, welding is the most common process. From experience, we know how welded components must be handled to satisfy the high safety requirements. However, we still have to learn how best to take advantage of implementing the new geometrical freedom in component design. Toward that end, we will have to perform many structural tests and trials over the coming years. The result will be a novel “bionic” aircraft design, I’m sure of it.”
Elucidating his vision for the future of 3D printed aerospace parts, Emmelmann asserted, “We won’t be printing complete aircrafts, even in ten years. But I’m confident that in the future laser additive manufacturing will be capable of producing increasingly larger and more complex components in a cost-effective manner. This will be possible thanks to the rapid pace at which the system technology is being further developed.”

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