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The Marines land on HP metal jet 3D printing to keep amphibious vehicles in action

June 4, 2020

The beast may be built to carry the fight, but its bulletproof skin has been protecting the lives of U.S. Marines for nearly half a century.  

Weighing 26 tons—more than some whales—this behemoth was, nonetheless, born to swim. It cruises through hostile waterways at 8 mph. And it is always headed to the beach. 

An AAV, the vehicle for which the US Marine Corps are testing  HP 3D Printed parts

An AAV, the vehicle for which the US Marine Corps are testing HP 3D Printed parts

Meet the AAV, short for Assault Amphibious Vehicle, which has been the leading option to carry Marines from ship to shore atop its caterpillar tracks since 1972. Roomy enough to shield more than 20 humans and haul a storehouse of supplies, its fleet is stationed from the Middle East to the homeland, numbering 1,024 vehicles in all. The Marines just call it the “AmTrac.” 

But the AAV’s days are numbered. The Marine Corps plans to phase out the vehicles during the next 10 to 15 years. It may be as natural as a fish in water, but that inevitable future has complicated the process of keeping them running in the meantime.  

rivate manufacturers, the traditional source for AAV replacement parts, now have less incentive to make those parts. That reality is impacting the Marine Corps supply chain, leaving dozens of AAVs sitting idle for months—and in a worst-case scenario, it could mean sending some Marines into battle without their protective landing crafts.  

To keep the AAV program fully afloat through its golden years, the Marine Corps is relying on HP Metal Jet 3D printing to produce hundreds of replacement parts, including bolts, mounts, brackets, cranks and couplings.  

“This is a critical part of our future, ensuring readiness of those in uniform,” says Kristin Holzworth, chief scientist for the Advanced Manufacturing Operations Cell, part of the Marine Corps Systems Command.  

About 200 AAV parts have been printed on HP Metal Jet printers at Parmatech, a manufacturing company in Northern California. The technology allows the parts to be printed rapidly and in mass—a shift that doesn’t simply steady the supply chain, it provides replacement parts faster than ever, says USMC Col. Patrick M. Col. Tucker.  

“Metal Jet is big advantage to us,” says Col. Tucker, commanding officer of Combat Logistics Regiment 15 at Camp Pendleton, California, where Marines train in AAVs. Col. Tucker helps manage the metal jet printing program. He also served in the Iraq War.  

Traditionally, many AAV parts were made with subtractive manufacturing, a process that starts with a solid block of material that slowly gets sliced and shaped to create a specified shape. In contrast, HP Metal Jet printers precisely place up to 630 million nanogram-sized drops per second of a liquid binding agent onto a powder bed, forming a part, layer by layer. The water-based liquid is made with a polymer that binds metal particles together during printing. The powder bed is then cured or heated, leaving a solid, high-strength part.  

Examples of replacement parts that have been 3D printed for AAVs

Examples of replacement parts that have been 3D printed for AAVs

"Being able to clasp (what used to require) 50 different, subtractive-manufacturing lines into a couple of prints, you almost can't even put words to that,” Col. Tucker says. “The efficiencies that are likely to come from that are absolutely astronomical.”

Metal jet printing also removes the need to weld together assemblies of multiple pieces. Instead, they can be printed as a single part.  

“It gets rid of welds period, which is absolutely amazing,” says Sgt. Jonathan Anderson, part of the 1st Supply Battalion at Camp Pendleton.  

“A weld is always a weak point. We are actually increasing the life cycle of these parts and potentially increasing the life cycle of the vehicle,” Anderson adds. In time, that should keep the AAV fleet better serviced and fully in action—once the Marine Corps’ metal jet program completes its testing.  

Members of the Marine Corps and others who are parts of the taskforce using HP Metal Jet printers to make AAV parts

Members of the Marine Corps and others who are parts of the taskforce using HP Metal Jet printers to make AAV parts

For now, however, the industrial supply chain “has gone cold on us,” Col. Tucker says. Many private companies have pivoted toward more lucrative manufacturing opportunities. According to a Marine Corps analysis conducted in April, many AAVs had been waiting an average of 140 days to receive replacement parts. Some parts have been backordered for more than a year. 

"It takes those Assault Amphibious Vehicles offline,” Col. Tucker says. “As of (April 1), here at Camp Pendleton, we had 41 of our 214 vehicles in maintenance. It’s a very important platform to our combat readiness.”

“That,” Col. Tucker adds, “is what being able to print today can do for us.”

"As for what current supply chain issues mean for Marines who are deployed to distant bases, who may need the AAVs to safeguard them should conflicts erupt? “In extreme times where we have a kinetic operation, you could foresee that we may have to send (Marine) units without that,” Col. Tucker says. At present, the parts shortages also mean fewer AAVs are available for training Marines at Camp Pendleton. 

This spring, 3D-printed parts are undergoing the first phase of testing to confirm that they fit, that their size and weight are accurate, and that they are functioning properly in a test vehicle. So far, all the parts have passed, Holzworth says. “Very promising work,” she adds. 

Phase two of the testing will gauge the parts’ reliability by installing them into the AAV testing vehicle and putting that vehicle into motion. 

But the push to outfit all 1,024 AAVs with printed parts may have far broader implications for the Marine Corps, the second-smallest branch of the U.S. armed services. (Only the Coast Guard is smaller). 

Its size contributes to the USMC’s “shallow” supply chain, Col. Tucker says. That means parts needs within the Marine Corps are not nearly as large as, say, the scale of parts required to keep the U.S. Army in perpetual operation. Consequently, industrial manufacturers are somewhat less motivated to devote their factories and machines to parts-making for the Marines.  

One of 1,024 AAvs the US Marine Corps hopes to outfit with 3D-printed replacement parts

One of 1,024 AAvs the US Marine Corps hopes to outfit with 3D-printed replacement parts

"That’s why something like rapid metal is so interesting,” Col. Tucker says. “This capability would allow us to move around that problem.” 

While the AAV serves as a “good Guinea pig tester,” Col. Tucker says, his team is also looking at other platforms beyond the assault amphibious vehicle that may be good candidates for printed parts.

Of course, the Marine Corps’ mission to help defend U.S. interests in far-flung places has sometimes stretched that shallow supply chain to extremes. And that offers USMC officials yet another reason to take a hard look at metal jet printing to fill the gaps, says Scott Adams, a civilian member of the USMC team working to equip AAVs with printed parts.  

“We go into some pretty remote areas and the supply chain is just not available to us yet,” Adams says. “So, the ability to make our own parts at the point of need is critically important.” 

“It’s all about equipment readiness,” Adams adds, “and about our ability to deploy into an area or to sustain ourselves while we are there.” 

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