Manufacturing woes could sink US sub fleet. Can 3D printing save it?

DANVILLE, Va. ­— A new building with a glass facade sits in a largely empty industrial park here in rural Southside Virginia.

Inside, there’s no steam, no smoke and no soot. No sparks fly. No hot metals are poured. No echoing bangs of a hammer on an anvil.

Rather, it’s all white. White floors, white walls, white machines generating white noise as they print and finish small metal parts. It’s a far cry from a traditional factory churning out submarine components.

But U.S. Navy officials say this building, the Additive Manufacturing Center of Excellence, represents the future of the submarine industry — and perhaps the service’s only path to building the Columbia-class ballistic missile submarine and Virginia-class attack submarine on time.

The Navy has already used additive manufacturing to print small repair parts on ships at sea, including circuit covers and radio knobs that would be difficult and expensive for the service to access while deployed. But by next year, as the workload for the U.S. submarine-industrial base ramps up to its highest level in 40 years, the Navy will 3D-print metal parts as standard components for installation on new-construction submarines.

To bridge the significant gap between its small-scale use of additive manufacturing to date and the anticipated widespread reliance on the technology, the Navy has commissioned a flurry of activities to mature metal additive manufacturing — and Danville, Virginia, is at the heart of that effort.

The Additive Manufacturing Center of Excellence there is seeking to expand the supply chain for submarine parts by helping companies take up metal additive manufacturing.

There’s pressure on the Navy to make this technology work. Already the service spent $2.3 billion to expand and strengthen the submarine-industrial base, and it’s poised to spend billions more, with additive manufacturing being one of five focus areas of this spending.

“It is a manufacturing capacity imperative” if the Navy and its industrial base stand any chance of ramping up to building one Columbia- and two Virginia-class submarines every single year for the next decade, said Matt Sermon, the executive director at the Navy’s Program Executive Office Strategic Submarines.

The plan is not without risk, experts say.

“Progress is being made, but it’s still not a push-button technology where we can say: ‘Make this part with this material and you’ll get out what you need,’ ” said Kevin Jurrens, who leads the National Institute of Standards and Technology’s work on smart manufacturing.

The depths of the challenge

The Navy is trying to achieve a submarine construction rate not seen since the 1980s: It is simultaneously replacing its ballistic missile submarine fleet and growing an attack submarine fleet that today is only 75% of the Navy’s required size.

However, the industrial base of companies contributing to these submarines has shrunk more than 70% since the 1980s, from about 17,000 suppliers to 5,000. And the ramp-up in workload is happening relatively fast.

As recently as 2013, the Navy would begin building one Virginia sub each year. Starting in fiscal 2026, the Navy plans to perform five times that work — two Virginias and the much-larger Columbia every year — given the complexity of submarines.

Even the jump to two Virginia subs a year caused the construction line to miss milestones, and today some boats are a year or more behind schedule due to the COVID-19 pandemic. Related logistics and workforce challenges worsened the delays. The Navy now expects to return to on-time delivery by fiscal 2028.

But the service says the high-priority Columbia submarine cannot fall behind schedule.

Rear Adm. Scott Pappano, the program executive officer for strategic submarines who also oversees the overall submarine-industrial base program, said the Navy faces an uphill battle. Though the entire workload will quintuple, that actually creates a tenfold increase for some sectors like castings, which is already a weak spot in the supply chain.

Castings, or pouring hot metal into molds, is among the most challenged areas — and one that can be supplemented with metal additive manufacturing.

“We know where our constrained market sectors are,” Pappano said.

Whitney Jones, the director of the Navy’s submarine-industrial base program, said internal models show certain metal components will see up to a 6.4-times increase in demand when industry reaches its peak submarine construction rate.

The industrial base is already behind building these metal parts: Today, there are more than 100 so-called sequence-critical material parts — meaning they will hold up construction if they’re unavailable — that are delivered more than 300 days late on average but are eligible to be 3D-printed.

Printing these parts instead of casting them would mean each piece would take less time to make and would allow more companies to simultaneously produce them, reducing or eliminating delays at both the supplier and shipyard levels.

Jones said metal additive manufacturing could increase capacity for these metal parts by 15% to 20% in two to three years, while also improving the quality and cutting production time by as much as 90%.

As with plastic 3D printing, there are several methods for printing metal parts. The most common and mature one uses a laser beam to melt metal powder, which, layer by layer, creates the desired shape based on a digital model.

Pappano said 3D printing is the right approach.

“I take hot metal and I pour it into sand,” he said of traditional castings. “It’s very medieval.”

But with additive manufacturing, he explained, “I can control weld pool temperatures and deposition rates. … I can monitor that deposition, I can look for inconsistencies during the build of the thing, and then ultimately I can go do nondestructive testing on it or destructive testing to go prove” its quality.

How to print parts

The Navy in May installed a new ventilation diffuser on the Ohio-class ballistic missile submarine Kentucky. This otherwise unremarkable part — a metal vent cover that directs airflow — marked the first printed metal part to be installed on a submarine.

More recently, the Navy turned to 3D printing for a sanitation system valve on another ballistic missile submarine in depot maintenance in Bangor, Washington. The original manufacturer went out of business, and it would have taken two years to get a similar part through the traditional supply system.

The Navy instead took an existing valve, laser-scanned it, reverse engineered the part in a computer-aided design system, printed prototypes using different methods, tested them, and then delivered the final part back to Washington for final machining and installation.

Instead of a March 2025 delivery date, the part was ready for an October 2023 installation.

But officials say the Navy must move beyond these one-off efforts and scale up its work to design, qualify and install printed parts on submarines.

Sermon told Defense News his office began examining additive manufacturing after seeing some suppliers use the technology. The office spent the past year conducting small-scale experiments and “became convinced that [additive manufacturing] not only could, but must represent a 15[%] or 20% increase in our metal-forming manufacturing-industrial base — think castings, forgings, fittings, fasteners.”

The office is now focusing on six specific metals accounting for 15,000 to 20,000 individual components needed to build submarines. That list of parts includes 75% of components for new construction and in-service sustainment that are prone to delays or other challenges. In fact, three of those metals alone account for 50% of the casting delays that plague new submarine construction.

Separate from the efforts in Danville, Newport News Shipbuilding recently announced its collaboration with additive manufacturing specialist AMMCON Corp. to design and print a copper-nickel deck drain for installation on the Virginia-class attack sub Oklahoma and subsequent boats in the production line, which represents the start of including printed parts as a standard item in the supply chain. Copper-nickel is one of the key alloys the Navy is working with.

The Navy sees these low-risk parts — like the valve, the ventilation diffuser and the drain cover — as low-hanging fruit. Sermon noted about 20% of the parts eyed for 3D printing are considered low risk and could go into production today.

But Pappano said the Navy must, in parallel, mature the technology so it can print components related to the integrity of the hull, nuclear-related components and other critical parts.

Printing on demand

To expand metals manufacturing output so significantly, the Navy is working with the state of Virginia and industry partners at the Additive Manufacturing Center of Excellence to create a network of printing partners and a digital order book to manage the workload.

First, the team builds the technical data packages, or “recipes,” to print a part. Team members build and test and destroy prototypes to perfect the combination of printers and processes and metal alloys that make the best parts. Once they determine the best printing process for that type of part, they finalize the technical data package and seek certification from the Navy.

To date, the Navy has approved recipes for 28 parts, including a range of valves, brackets, handles, adapters and more.

The Danville facility won’t mass produce those parts. Instead, they’ll be farmed out to a growing network of builders.

Don Hairston, the general manager of Austal USA Advanced Technologies, which leads the Navy’s Additive Manufacturing Center of Excellence, said four companies have gone through an extensive process to get their facilities, machines and employees certified to be part of this network. Five more are to be “activated” — or certified to join the network — next quarter, and three others are in the pipeline.

Ultimately, Hairston told Defense News, the Navy envisions a network of 50 or more sites in the United States printing metal parts for new submarine construction. There could also be more in the United Kingdom and Australia to contribute to the trilateral AUKUS arrangement, he added.

Hairston said what the center is calling a digital order book will automate the process of ordering parts. For example, when the Navy puts out an order for 200 3/8-inch ball valves, Hairston’s team at the center of excellence will be able to see which vendors in the network have the right printing process and metal for that valve’s recipe. Among the qualified vendors, the team will also be able to see who has capacity for the job.

The digital order book is a work in process, Hairston said, but it’s on track to go live by the end of 2024. By that time, the Navy should have 15 printing partners in the network and at least 150 to 200 parts with approved technical data packages, he noted.

A race against time

The Navy needs to start mass printing these parts as soon as possible, according to Jones, the director of the Navy’s submarine-industrial base program.

“We are two years away from needing to be at one Columbia and two Virginias a year, and if we aren’t making bold moves that assume some level of shared risk, we’re not going to get there when we need to be there, and that brings in a whole different kind of risk,” she said.

But technical experts argue the technology isn’t quite there, particularly given the high standards involved in submarine work. Jurrens, whose NIST office is developing standards to guide quality-assurance efforts for advanced manufacturing techniques, said the qualification and certification for additive manufacturing remain significant barriers.

Today, he explained, an additive manufacturing company would have to qualify the material, the process, the machine and the operator, and then certify the final part. Any changes, such as a new employee using the printer, would restart the qualification process.

“It’s very time-consuming, very labor-intensive to get to that qualified step,” Jurrens said. “To do accelerated qualifications through things like simulation and other techniques, those capabilities are improving, but they’re not to the point where end users, stakeholders, want to rely on them.”

There also are questions around ensuring the quality of the final part.

Ron Aman, the additive manufacturing senior technology leader at research and development nonprofit EWI, said there are approved processes for finding and fixing defects in a cast metal part, but there’s still concern and confusion over how to do so on a printed part.

A growing trend — and one the Navy is using at its center of excellence — is installing cameras, sensors and microphones to monitor the printing process and identify defects in real time.

“We don’t want to make two parts and then break one [in destructive testing] and then say: ‘Ah, we think the other one’s good.’ What we want to do is, we want to make one part, we want to watch what we’re doing very closely and get that confidence, and then use what we learned from the process signals to inform our inspection criteria,” Aman said.

That’s something Sandra DeVincent Wolf, executive director of the Manufacturing Futures Institute of Carnegie Mellon University, is working on. The machines in her labs are rigged with sensors: high- and low-speed cameras, thermal imaging, images of the melt pool, images of the metal spatter, acoustic monitoring, and more.

All of these find signs of defects, and depending on the situation the printing could either stop and the operator starts over, or the defect could be noted for later inspection and repair.

She said the goal is to get to the point where not every item requires testing at the end. Due to increased confidence in the monitoring systems, perhaps only one in 10 might undergo testing at the end for quality, Wolf added, and eventually one in 100.

Another key technical hurdle relates to the types of printers the Navy will use. John Harrison, the senior vice president of global additive work at Phillips Corp., one of the lead partners at the center of excellence, said one of the most mature and trusted printing processes — powder bed fusion — can only make smaller parts.

Other techniques — such as wire-arc directed-energy deposition, laser-directed energy deposition and friction stir additive manufacturing — can make larger parts, but these technologies are newer, meaning there’s less data on the quality of their final products, he said.

Sermon of PEO Strategic Submarines said his office is working on a “moonshot” effort to print very large parts — critical pieces related to the hull’s integrity — that even a year ago were considered impossible to print. Based on the test results of those large printed pieces, the Navy will determine whether it can use newer methods to print large components.

Getting industry on board

None of the Navy’s plans to expand its metal manufacturing capacity through additive manufacturing will work if industry doesn’t start printing for the submarine-industrial base.

Josh Cramer, the director of education and workforce development at the Defense Department-affiliated public-private partnership America Makes, said there is a 50,000-person shortage in the additive manufacturing workforce, and that demand for these workers is set to increase in the coming years.

“We have to bring more people to the industry at large because we don’t have enough humans to even train to get into those roles,” he said.

America Makes is working on an outreach campaign to make potential workers aware of not only the jobs available within the additive manufacturing sector but also the training and education required for each job and where to get it.

Already some of the best-known shipbuilders are moving into additive manufacturing.

General Dynamics Electric Boat spokesman Daniel McFadden said the shipyard is working to recruit “new expert additive manufacturing suppliers entering the submarine-industrial base and building [additive] capability with existing suppliers where it makes sense for the product line.”

The firm wants to contribute to the ongoing effort to define approved procedures and testing for 3D printing so it can turn to printed parts in its supply chain, “particularly for higher-consequence parts where scarcity and long-lead times are a limiting factor to production.”

John Wilczynski, the executive director of America Makes, said the organization is also trying to expand the 3D-printing ecosystem. While there is an upfront cost to investing in printers and either staff training or new employees, Wilczynski said, the magnitude of the submarine construction workload in the coming years creates a clear demand signal for companies wondering if they’ll see a return on their investment.

“You can’t avoid the two-plus-one narrative right now,” he said, referring to the Virginia- and Columbia-class submarine production rates. “It’s very out in front of everyone that this is a major national defense risk. There’s power in that because it’s becoming more visible to people who may be trying to decide where they’re taking their business next.”