Updated Nov. 23 at 2.43 p.m. Eastern.

BREMEN, Germany — Space hardware builders say they fully expect 3D printing to revolutionize manufacturing, but cautioned that the technology is sometimes promoted without a full understanding of its pros and cons.

Manufacturers at Space Tech Expo Europe here said Nov. 21 that they are increasingly using 3D printing to build parts, but that the technology isn’t a simple as often presumed.

“There is such a misconception that you buy a [3D printer], plug it in, you put in your euros and that’s it — parts start popping out,” said Josh Mook, GE Additive’s innovation leader. “It’s really not anything like that. You have to have a respect for the technology and you still need a level of sophistication.”

Mook said GE Additive supplies 3D printed parts up to 10 meters in diameter for satellites and other engineering projects.

Gerald Hagemann, head of liquid propulsion engineering at ArianeGroup, manufacturer of the Ariane 5 and Ariane 6 rockets, said many engineers at ArianeGroup initially jumped on the idea of 3D printing as the best approach for anything, when it turned out it doesn’t always save costs.

“For prototyping, it’s perfect,” Hagemann said. “For the serial production, it really hasn’t been demonstrated that printing can bring the cost down.”

Hagemann said ArianeGroup has 3D printed parts on the Ariane 5, and more on the Ariane 6, which debuts in 2020, but that the company is selective in how it decides to leverage that manufacturing approach.

Ole Geisen, head of additive manufacturing engineering services at Siemens, said that for prototyping, 3D printing gives a speed boost that makes it advantageous, but he agreed that 3D printing for serial production is more difficult.

“We had designers who were very much capable of designing for performance and designing for manufacturability, but designing and engineering for cost in [additive manufacturing], people haven’t really put a lot of effort into it,” he said. “This is now something we have to push very hard.”

Siemens has a team of around 150 people focused solely on 3D printing, Geisen said. The company 3D prints parts for its own products and for customers, including some in the space industry, he said.

Hagemann said one part ArianeGroup is 3D printing for Ariane 6 is an injector head, because additive manufacturing reduced the part count from thousands down to one. That created new challenges, however, since the engine part was no longer easily inspectable, he said. Even X-rays don’t work because the part is made of heavy metal, he said.

Mook said GE Additive reduced the part count inside a jet engine from around 850 to 12 using 3D printing.

“What I always tell people is that it is an amazing tool,” he said. “It lowers the barrier to entry in a huge way, it changes the way we approach problems, but it’s not a replacement for engineering.”

Mook said GE has spent more than $2 billion on standardization and qualification just for 3D printing.

However, GE Additive spokesperson Shaun Wootton said by email Nov. 22 that $2 billion is GE’s total investment in additive manufacturing, not just standards and certification.

Samuel Senese, deputy head of mechanisms and products at satellite and rocket builder OHB, said 3D printing has limited applications for remote sensing satellites, since optical components can’t tolerate all the same coatings as other spacecraft parts. He said 3D printing needs more investment, but is headed in the right direction. Others agreed.

“There is no stopping [3D printing] anymore, not even in space,” Geisen said. “It’s only a matter of timing and how much it will cover.”