Complex designs can slash the weight of spacecraft parts, but may carry hidden costs

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LOS ANGELES — By combining additive manufacturing with advanced processing power, companies now can print the optimal design for many spacecraft parts. No longer angular or boxy, the new parts “look sexy for the first time,” said Franck Mouriaux, RUAG Schweiz AG aerospace structures general manager said Oct. 19 at the Additive Aerospace conference here.

Engineers are learning, though, that the hardest part of this process known as topology optimization is figuring out exactly what features make a part optimal.

RUAG, for example, uses topology optimization to reduce the mass of spacecraft parts, which means customers can allot additional mass to commercial payloads. Mouriaux warned, however, that the complex designs may carry hidden costs.

Is the new additively manufactured part difficult to print? Will it require extensive processing after the printing is completed? Can it be inspected and tested easily?

“Some folks like to say with additive manufacturing, you get complexity for free,” said Michael Gorelik, Federal Aviation Administration chief scientist and technical adviser for fatigue and damage tolerance. “My contention is there is no such thing as a free lunch.”

In particular, Gorelik highlighted the challenges companies face when inspecting additively manufactured parts.

“There may be times when a little more material can minimize post-processing, which is a much higher cost than the small amount of additional material,” said Charlie Duncheon, North American head for Airbus APWorks, an Airbus subsidiary charged with sharing aerospace technologies and modern production innovation with new customers.

For engineers, correctly formulating the problem they are trying to solve may be the most challenging task, said Jon Meyer, Airbus additive manufacturing processes technology roadmap owner.

In some cases, engineers need additional education and training, said Alicia Kim, University of California San Diego professor in structural and material optimization.

“Engineers were not trained to formulate the problem,” Mouriaux said. “They were trained to find solutions.”

Frustum Inc. helps engineers narrow down the problems they need to address through its software. “We enable the designer to make a judgement about what is important,” said Jesse Coors-Blankenship, Frustum chief executive and founder. “If you have too many objectives, you can start to get a muddled answer.”

RUAG is honing its designs by working with prime contractors to gain a thorough understanding of how parts will be used in space. That effort helps them understand which characteristics are most important, Mouriaux said.