The sky’s the limit for laser-sintered plastics in aerospace

August 26, 2010

Unmanned vehicle manufacturers are increasingly employing unmanned fabrication techniques to create critical components. Plastics and metal laser-sintering equipment supplier EOS GmbH (Münich) has seized on the opportunity for its "e-manufacturing" technology, watching business within aerospace, which includes unmanned vehicles, grow steadily since the company entered the market in earnest around four years ago. This August, the company again participated in the Assn. of Unmanned Vehicle Systems International's (AUVSI) annual exhibition and conference, taking place from August 24-27 at the Denver Convention Center in Denver, CO.

EOS's Udo Behrendt, key account manager aerospace, said that since many of its customers are rapid-manufacturing service bureaus that sell into a variety of sectors, it is hard to definitively measure how much the aerospace market has expanded for EOS, but he estimates that particular area of business has roughly tripled for EOS since it began actively pursuing it.

Andrew Snow, regional sales director for EOS of North America (Novi, MI) noted that unmanned vehicles, like the military drones remotely patrolling various hot spots throughout the world, are a large part of that growth. Since EOS first participated in the AUVSI event four years ago in Orlando, Snow says the show itself has doubled in size with EOS's technology growing along with it. "The presence of laser-sintered parts has really grown at AUVSI," Snow said.

Laser-sintered plastics pervasive at AUVSI
In addition to its own booth at the event, five EOS customers were also exhibiting, including Northwest UAV Propulsion Systems (McMinnville, OR), which was actually running an EOS Formiga P 100 at its stand. Alex Dick, VP SLS operations at Northwest UAV, and former application engineer at EOS, said his company bought its first EOS system, an Eosint P390 with a build volume of 340 by 340 by 620 mm (13.4 by 13.4 by 24.4 inches), about two and a half years ago. As demand increased, it added a larger Eosint P370, with a build volume of 700 by 380 by 580 mm (27.6 by 15 by 22.9 inches) about one year ago.

As the acceptance of laser-sintered parts grew within the market and pushed them from functional prototype applications to full-fledged production components, Dick says Northwest UAV initially outsourced laser-sintered parts. Seeking greater control, the company added the EOS technology and is now considered an expert in the creation of tough thin-wall parts. At the company's booth, Dick shows off a laser-sintered nylon 12 component with the durability to operate as ducting in an air-cooled engine but enough flexibility to boost functionality. The company has also laser-sintered conformal fuel tanks for unmanned vehicles that must fit within a very tight engine envelope.

"This industry is so dynamic and the designs change so often, that it lends itself to laser sintering," Dick said. "There's no big penalty for iterating a design a number of times." Northwest has gone from supplying such parts from one client to four, as industry understanding of its capabilities increases.

At the same show, Jim Williams, president and CEO of Paramount Product Development Specialists (Langhorne, PA) showed off several production parts that utilize laser-sintered plastics. On a podium at the front of his booth is an engine built for Honeywell, which features four laser-sintered control vanes at its base.

In their initial design, the vanes were to be constructed from carbon-fiber composite sheet, with pieces formed over mandrels and then joined. In their new design, they're laser sintered from nylon 12 with hollow wall sections, cutting weight in a design feature that would be nearly impossible using any other manufacturing process. At this time, the company makes around 80 of the control vanes a week using an EOS system.

Expanding market, with Joint Strike Fighter on the horizon
EOS estimates that aerospace currently makes up around 12-14% of its revenue, but that figure continues to grow. The company opportunistically finds its technology at the confluence of low-volume manufacturing and extreme high-performance parts. "The technology is being accepted more because it represents a more economical way of doing low-volume manufacturing," Behrendt explained. Using the world's most-sold aircraft, Boeing's 737, as an example, Behrendt pointed out that last year only 372 were built. That's a low number in itself, but if one considers that many interior components, for example, are different from carrier to carrier, the build volumes shrink even further.

In addition to low-volumes, Snow and Behrendt pointed out that aircraft are expected to have very long service lives, up to 50 years, and will require spare parts over that entire time. If a supplier had used tooling to create the parts, they'd be expected to maintain and store those molds. With 3D laser sintering, Snow said suppliers can have "digital warehousing," with a part's CAD file ready at a mouse click. "You can maintain inventory on your laptop," Snow said.

EOS recently launched a Victrex polyetheretherketone (PEEK) grade for its sintering machines, and within the next six months is hopeful that its technology will win bids to supply components for the United States Air Force's new Joint Strike Fighter program.


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