Additive Manufacturing

JAN 2018

ADDITIVE MANUFACTURING is the magazine devoted to industrial applications of 3D printing and digital layering technology. We cover the promise and the challenges of this technology for making functional tooling and end-use production parts.

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Page 14 of 43

AM / Taking Shape 13 serve as the last piece of the puzzle—only because the other three pieces are in place. "One of our mottos is, 'We don't just print parts; we manufacture parts to print,'" Whittaker said during a keynote speech that preceded a recent tour of Incodema3D's facility. "We brought additive manufacturing into a core manufacturing environment with multiple toolsets—CNC, precision sheet metal, photochemical machining and other manufacturing capabilities—versus the typical methodology of a printing com- pany realizing that you need all of these ancillary processes to complete a part. So we took a sort of backwards approach, which for us was only logical." Of course, what we're talking about here is vertical integration. "Without that ability," Whittaker says, "we're kind of throwing a part over the wall and hoping that (the machinist) catches it, and our likelihood of success is very limited. It's taken years for our additive programmers and our CNC programmers to develop that understand- ing—where we need to add on stock, or use work-holdings, or add material in certain areas. There's a very long process chain, but having it all integrated into our operation is a major advantage." Whittaker points out that for all of Incodema3D's successes, it was just three years ago that the company had only three additive parts in production for customers. Today it has 15. A year from now he expects that number will be in the hundreds. "We're production ready; some of our customers aren't quite there," he says. "We may not be using the full capacity of this facility today, but very soon, we will. Very soon." After decades of research, billions of dollars in global investment, and soul-crushing tech- nological delays, the aerospike engine—a single-stage-to-orbit technology once dubbed "the holy grail of the spaceship movement"—may finally be getting off the ground. And the recent announcement that engineers from Monash University and Amaero success- fully designed, built and tested an aerospike engine suggests that additive manufacturing promises to play a significant role in making this moon-shot a reality. The aerospike is a single-stage-to-orbit (SSTO) engine, meaning that much of its greatness lies in its ability leave our atmosphere without the added payload of multiple-stage boosters. The engine's chief attribute is its ability to maintain thrust ef- ficiency from ground level into outer space. But despite more than 50 years of testing and $1.5 billion investment by NASA and others in the technology, an aerospike engine has never entered service. The engine employs a high-efficiency nozzle, or spike, to direct the flow of high-pressure gas emanating from the thrust cells. The surface of the spike restricts expansion of the gases against the curved inner wall of the rocket, while a cavity at the top of the spike allows a subsonic flow field to recirculate at its base. Thrust pro- duced from the pressure against the spike combines with the recirculating flow field to produce a powerful, highly efficient engine that is not as susceptible to changes in atmospheric pressures. As the altitude increases, the pressure boundaries shift from the nozzle and upper base to the inner wall of the enclosure, which keeps the nozzle performance at near-theoretical maximum across changing atmospheric conditions. The aerospike's design and functionality are immensely complex to realize through traditional manufacturing methods, due mainly to the inner geometry of the rocket's inverted-bell shape, and the complex cooling channels necessary to keep the engine from outright melting. AM Design May (Finally) Launch the Aerospike Engine By Brent Donaldson A render of the 3D-printed aerospike engine. Note the cooling channels that line both the spike and the rocket body.

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