Why Additive Manufacturing Works for the Aerospace Industry

By Catherine
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By Catherine Bolgar

The aerospace industry is leading innovation in additive manufacturing on several fronts, including applications, materials, processes and design.

Additive manufacturing (AM), also known as 3D printing, may be well-suited to the aerospace industry, as long as the technology is certified and the cost comes down. This industry needs to make complex parts in low volumes from high-performance materials, while constantly seeking new ways to lower costs. While AM can cost more than traditional machining methods, it provides savings on materials—which can be substantial when using expensive metals such as titanium.

“There has recently been a real tectonic shift in the way large aerospace companies are investing in additive manufacturing,” says Kamran Mumtaz, lecturer in additive manufacturing at the Centre for Advanced Additive Manufacturing at the University of Sheffield, U.K.

Here are some areas of innovation:

NEW APPLICATIONS

AM originally was used to make plastic models and prototypes for basic form and fitting applications, but not for functional testing. Then AM was used to make plastic parts for functional applications. “More recently, it has been used for brackets, ventilation ducts and parts to hold wires and cables in place,” says Terry Wohlers, president of Wohlers Associates, a Fort Collins, Colorado, AM consulting firm. “Now, more parts are being made of metal AM, and I have seen no fewer than 25 new and innovative designs from one major aerospace company, alone,” he says.

Aircraft Turbine“With traditional manufacturing, many parts must be assembled from smaller pieces, because of the limits on what shapes can be cast, milled or molded,” Mr. Wohlers explains. “The technique of building in layers allows for parts to be combined digitally that could include 20, 50 or 100 parts into one, two or three parts,” he says. Fewer parts means big savings in expensive manufacturing processes, assembly, labor, inventory and maintenance, he says, adding that companies also are seeing a reduction in certification paperwork, because each part must conform to the strict requirements of regulatory agencies.

IMPROVED MATERIALS

Polymers, or plastics, are the most mature technology, but titanium 6-4, which can be difficult to grind or weld, is the most popular because of how well it works in AM, along with aluminum, nickel, stainless steel, and cobalt chrome.

New materials would require going through a qualification process, which takes several years. However, researchers are looking at feed stocks, optimal particle sizes and recyclability of leftover powder, says Bill Peter, director of the Manufacturing Demonstration Facility at Oak Ridge National Laboratory in Oak Ridge, Tennessee.

The laboratory recently made the largest 3D-printed component, which wasn’t a plane part but a trim tool to make the extended wing section of the new Boeing 777X. Traditionally made of metal, the AM tool was made of a composite of polymers with chopped carbon fiber. The AM tool is faster and cheaper to make than a metal one, Dr. Peter says.

Work is being done on AM composites that can withstand high pressures and temperatures as high as 176°C (350°F). “It would have tremendous savings for tooling in the composite industry for air applications,” he says. “Eventually, we want to understand how to bring the best materials to a problem set and come up with hybrid solutions,” using metals, polymers and ceramics.

AM makes it possible to alter microstructures as the materials are processed, which can affect their strength and flexibility. For example, one AM company “can blend two or more polymers and, consequently, can make one location of a part rigid and gradually transition to soft and elastic in another location,” Mr. Wohlers says.

IMPROVED PROCESSES

jet engineThe most common AM method for making metal parts is to lay a bed of powder and to melt it, layer by layer, with a laser or an electron beam, following a programmed design. However, the AM machines remain limited in size, so most of the parts made are small and in limited volumes.

“At Sheffield, we’re developing new manufacturing processes that improve on efficiency, build speed and enhance the properties of the components,” Dr. Mumtaz says. “We have a metallic-powder-bed manufacturing process, called diode-area melting, or DAM, that has the potential to be 10 times faster than conventional selective laser melting.”

Selective laser melting uses a single laser. Increasing speed requires a more powerful laser or integration of multiple lasers. “DAM replaces a single-point laser with up to 20 laser diodes. You can scan an entire powder bed faster,” he says.

The University of Sheffield also is building a 3D printer that uses high-speed sintering of polymers, with an infrared lamp on an inkjet printer, that’s about 100 times faster than laser sintering.

IMPROVED DESIGNS

Topology optimization is the mathematical technique employed to find the best way to “use minimal materials and minimal weight, but fulfill the needs of the part,” Mr. Wohlers says.

When grinding a part, 80% to 90% can be scrap. Additive Manufacturing is the opposite of that: you can do a highly convoluted, complex shape that can reduce materials and weight by 40% to 50% sometimes.”

INTERNET OF THINGS

AM machines are equipped with cameras and sensors to track the fabrication, point by point, including in the middle of a part as it’s being formed. “We’re capturing the information and using data analytics to see what’s going on,” Dr. Peter says.

Eventually, manufacturers would like to incorporate sensors into the parts, to monitor them for temperature, humidity, vibration or other data. However, sensors and metal or polymers are “dissimilar materials—and that makes things complicated,” Dr. Peter says. “While research activities are stepping up in the area of embedded sensors, there is a need for continued research to commercialize.”

 

Catherine Bolgar is a former managing editor of The Wall Street Journal Europe, now working as a freelance writer and editor with WSJ. Custom Studios in EMEA. For more from Catherine Bolgar, along with other industry experts, join the Future Realities discussion on LinkedIn.

Photos courtesy of iStock

MIT’s experimental 3D-printed sneaker shape-shifts to your foot

By Alyssa
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Byline: Marc Bain

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At the moment, 3D printing is still mostly about experimentation. While it hasn’t quite taken off to revolutionize the way consumer products are made just yet, it does offer a lot of exciting, innovative ideas, especially in the realm of sneakers.

MIT’s Self-Assembly Lab, a group focused on research into “active” materials, is working in collaboration with product designers Christophe Guberan and Carlo Clopath on one of the most unique footwear possibilities involving 3D printing: It’s a shoe that can be “programmed” to match the contours of your foot.

Their Minimal Shoe, as they’ve dubbed it, is created in a unique process. They stretch out a textile and then 3D-print lines of plastic in varying layers and thicknesses on it—essentially, the structure of the shoe-to-be. Next they cut out the portions of the textile they want. Released from the original stretch, the textile will “jump” into a new shape according to the arrangement of the 3D-printed lines left on it. Hypothetically, you could either custom print a shoe for each wearer with just a few lines of extruded plastic, or you could make a nearly one-size-fits-all shoe, since the stretchy textile will conform to any given shape.

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Skylar Tibbits, one of the directors of the lab and a research scientist in MIT’s architecture department, tells Quartz they’re investigating both possibilities, and that the “morphability” of the textile could make for a more comfortable and adaptable type of performance footwear.

The whole shoe wouldn’t have to be created with this method either. Just the upper could be, or portions of it, and then it could be attached to a more traditional sole. It’s also relatively easy to make, compared to 3D printing an entire sneaker.

“Imagine using active materials to produce one-size-fits-all shoes, adaptive fit, and self-forming manufacturing processes,” a statement by the lab says. “This technique would radically transform the production of footwear forever.

Although the shoe is still a work in progress, Tibbits told The Creator’s Project that a large sportswear company is currently interested in the process, though he isn’t certain what might come of it.

Actually, of all the consumer-goods industries exploring uses of 3D printing and customizable textiles, sneaker makers could well be among the first to bring products to a mass market. Adidas has already introduced a 3D-printed midsole that could give every customer the perfect fit, and Nike’s COO recently expressed his confidence that we’ll soon be able to 3D-print Nike sneakers at home or the nearby Nike store. Both have also shown an interest in finding new ways of manufacturing lightweight textiles that can stretch and contour to the wearer’s foot, as in the knit uppers that have been so popular for both.

The Self-Assembly Lab is working on other projects too, including materials that can transform in response to outside stimuli. So, for instance, something like sneaker laces that could tighten from heat or the energy of a small battery. Currently it’s collaborating with Airbus on creating a dynamic carbon-fiber component for the company’s airplane engines.

The Minimal Shoe in particular came about when the lab received an invite to design footwear for the “Life on Foot” exhibition at the Design Museum in London.

To discuss this and other topics about the future of technology, finance, life sciences and more, join the Future Realities discussion on LinkedIn.

Additive manufacturers lead a design revolution

By Catherine
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Written by Catherine Bolgar
3D printer

Additive manufacturing—industrial-strength 3D printing—is shaking up the world of industrial design.

The global market for additive manufacturing (AM) grew 35% in 2014, as companies increasingly find new ways to use the process. AM builds up objects layer by layer, as opposed to conventional, or subtractive, manufacturing methods, which cut or grind down a solid piece to the desired form.

As a result, AM is capable of producing new shapes that would have been difficult to create using conventional methods. It can also fashion new internal architecture that’s hollow or contains lattices, instead of being solid. This not only reduces the amount of material used, it also makes the end product lighter. And it allows us to rethink design.

Additive technology has opened up the door for us to conceive shapes and designs,” says Joshua Mook, engineering manager, additive technologies, at General Electric Aviation in Cincinnati. “Shapes are now free, complexity is free, so we can go satisfy the physics and the shapes in the way they want to be satisfied.”

Cooling devices, such as car radiators or laser cooling systems, can now be designed with interior channels that aren’t possible when using conventional manufacturing tools.

3D printer concept“Designers can take technologies that were mature before and now can add functionality,” says Matt Wraith, group leader, defense technologies engineering division, at the Lawrence Livermore National Laboratory in Livermore, California. “A good designer is going to think about the manufacturing process when designing a part, but you have [far] fewer restrictions with additive. It’s a challenge for some technical staff, because they have to forget all the things they learned in the past.

The new mindset is leading designers to seek inspiration from nature rather than manmade structures.

“Historically we have handled problems like high loads by transferring some of the load to another member or out into the airplane,” Mr. Mook says. “All our solutions used to look like textbook solutions, with beams, right angles, things that are easy to cut.

In the future, ”they’re going to look more like bones in the human body,” he adds. “They’re not going to have constant cross-sections or predictable or recognizable shapes. They’re going to look much more freeform.”

AM is particularly suited to evolutionary structural optimization, a design idea from the 1990s based on removing non-load-bearing materials, allowing structures to be hollowed out as much as possible.

These new geometries can affect a material’s properties.

Engineer working on a 3D printer“In many cases, you go from molten to solid very quickly. That has negatives and positives. If you truly understand it you can use that to your advantage and generate materials that are stronger than in the past, like in a cast that solidifies very slowly. If you don’t understand it, it can lead to cracking and weakness,” Mr. Mook says. “Just as forging and casting are different, we treat AM materials differently from materials from other processes. We do extensive testing.”

Internal passageways also can alter a part’s performance. GE Aviation used AM to make a jet-engine fuel nozzle, which has many passageways for air, fuel and thermal isolation. “Fuel comes in ice-cold from the wing tanks,” Mr. Mook explains. “Inside the jet, it’s extremely hot. When you have extreme cold and extreme heat next to each other, it produces thermal stress. That has limited designs for a long time. Now, we can do a better job of getting fuel where we want it and air where we want it, and the parts can have longer lives.”

AM also offers the unique ability to change the density of a material within a single piece, though the technique is still at the research stage.

On a simpler level, AM is democratizing design. “You can reverse-engineer an item,” says Mr. Wraith of Livermore Lab.

If you have an existing part, you can just scan it. There’s no need to design it.”

Online databases contain open-source designs, while other designs can easily be bought.

“That’s the future,” Mr. Wraith says. “You download the design for a part and print it and you’re good to go.”

 

Catherine Bolgar is a former managing editor of The Wall Street Journal Europe. For more from Catherine Bolgar, contributors from the Economist Intelligence Unit along with industry experts, join the Future Realities discussion on LinkedIn.

Photos courtesy of iStock



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