NOVI, Mich.--Designs for unique, complex aircraft components, many of them impossible to create using traditional manufacturing processes, have spurred greater demand for additive manufacturing processes. Laser sintering, for example, is being used increasingly in the fast-growing market for unmanned aerial vehicles (UAVs).

"The huge growth of the unmanned-systems market has triggered a wave of innovative and unique designs," says Udo Behrendt, aerospace account manager for laser sintering systems manufacturer EOS. "Our customers are using metal and plastics laser-sintering to push the boundaries of those designs."

While laser sintering can be used to create plastic parts, direct metal laser sintering (DMLS) can be used to create titanium aerospace components and prototypes. Both plastic and metal laser sintering are said to be already widespread in UAV and other aerospace applications because of their ability to produce parts that are durable, lightweight, and complex. The technology requires no tooling, resulting in time and cost advantages and making re-designs and customization easy and affordable.

One of the companies employing laser sintering to manufacture aircraft parts is McMinnville, Oregon-based Northwest Rapid Manufacturing (www.nwrapidmfg.com), part of the Northwest UAV Propulsion Systems (NWUAV) family of companies. Northwest Rapid manufactures production parts and prototypes for NWUAV using its EOSINT P 390 and P 730 laser sintering equipment. Together, the companies provide parts and assemblies, including engine and cooling components for UAVs made by Insitu, Inc., and others. In addition to being stable in hot environments, the components are tough, pliable, and robust in harsh conditions that include exposure to fuel.

"Manufacturers of UAVs face stringent demands, both for part requirements and delivery schedules," says Alexander Dick, vice president of laser sintering operations at Northwest Rapid. "EOS laser-sintering equipment enables us to meet tight tolerances, ensure component strength and performance, and deliver parts on or before deadlines."

Another company, Solid Concepts, has used selective laser sintering (SLS) to manufacture flight structures for Aerotonomy's new Cruise-Efficient ESTOL research aircraft. The aircraft's form-fitted seven-gallon fuel tank, as well as all of the primary structures that enable the advanced high-lift technologies--such as leading-edge blowing, circulation-control flaps, and airflow plenums--were manufactured with EOS laser-sintering equipment. Solid Concepts, headquartered in Valencia, California, manufactures plastic laser-sintered aerospace parts from a wide range of materials.

"On any given UAV system, once its customer and field use changes, the only features that stay the same may be the frame and most of the fuselage," says Frederick Claus, business development manager at Solid Concepts. "The manufacturing flexibility and speed of laser-sintering have proved their worth in this industry time and again."

Among the materials currently available for laser-sintering of UAV components are several polyamides, including a flame-retardant material; EOS PEEK HP3, a high-temperature thermoplastic polymer; titanium; cobalt chrome; and IN718, a nickel-chromium super alloy. Additional materials for UAV and other aerospace applications are in development.

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