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3D printing may be a new future in Navy ship construction

December 24, 2018

NEWPORT NEWS, Va. (AP) — An arm passes across a plate in the big machine, depositing powdered metal before a laser fuses it all together.

Wipe. Zap. Wipe. Zap.

Hour by hour, and layer by painstaking layer, the machine, a 3D metal printer built by 3D Systems, hums away.

Wipe. Zap. Wipe. Zap.

“This build has over a thousand layers so it’s just slowly making its way through,” Dan Hebert, an engineer at Newport News Shipbuilding said. “It’ll take a little over a day. It runs continuously.”

A little more than two miles from where workers at Newport News Shipbuilding are assembling the future aircraft carriers John F. Kennedy and Enterprise along the James River, a new tangent in the future of shipbuilding has been slowly taking shape in a nondescript office in an industrial park.

The shapes on this day were a collection of small cubes and rectangles, about 3 to 6 inches tall, designed by Kyle Wade — a Newport News Shipbuilding mechanical engineer and Navy reservist — via 3D modeling software and uploaded to the printer rather than being cast in a foundry. The pieces were being printed to test for strength and quality.

“We look at the microstructure as well as the strength properties,” Hebert said as he stood near the machine, watching as the pieces took shape through a small window in its side. “So, when we compare traditional properties, or traditional processes, we’re trying to make sure that this process is as strong as our traditional cast.”

3D printing, also known as additive technology, is not new. It’s been used for years and is common for producing plastic prototypes and medical devices. The Navy has used it for other purposes.

In October, Naval Sea Systems Command announced that it was upping the ante when it approved a prototype 3D-printed metal drain strainer for installation on the Naval Station Norfolk-based aircraft carrier USS Harry S. Truman. The part will be installed in coming weeks in the carrier’s steam system for a one-year trial.

Manufacturing a product for use on a Navy ship system requires significant testing before it can be certified for fleet-wide use. Engineers at Newport News Shipbuilding approached the Navy with the idea a few years ago but there was no rule book for 3D metal printed objects, or specifications to work from, Don Hamadyk, director of research and development, and John Ralls, an engineering manager and Navy reservist, said.

“We’re still paving the road because the Navy, rightfully so, has to pay a lot of attention to the reliability of the parts, safety of their sailors and operability of their ships” Hamadyk said. “So, the technical work that we’ve done over the last, really, four years is all aligned toward making the Navy comfortable with the parts that are going on their ships.”

As Newport News Shipbuilding developed its own qualifications, the Navy worked separately on its specifications for industry, Justin Rettaliata, who handles the approval of 3D printed components for ship installation for NAVSEA, said. Those specifications include details from the process and materials used to the tests that must be performed.

“For casting and forging, you know, we have reams of data from hundreds of years of experience on what the material properties are,” he said.

The part being installed on Truman took three days to build and was printed at a Newport News Shipbuilding partner, spokesman Duane Bourne said. It was originally a cast part made that required a lead time of up to nine months, Rettaliata said.

The Navy is looking to 3D printing as a way to skirt those long lead times for critical parts, as well as a way to replace pieces that may be obsolete. It may also prove a less expensive method when the Navy needs only a few replacement parts rather than having to order a large lot, Rettaliata said. The Navy is discussing other 3D metal printed components with the shipbuilder as well.

The valve made for the Truman “met or exceeded” the requirements for the traditionally cast part, Rettaliata said. After a year of use, it will be cut out and go through another battery of tests.

“There’s not a lot of data for operational testing,” he said. “This will go through a year of, you know, use. Whatever that use might be, So this will allow us to do testing, see how it holds up for corrosion, see if there’s any cracking.”

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Information from: The Virginian-Pilot, http://pilotonline.com

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