Military Scientists Developing New 3-D Printing Applications

With the advent of cheaper printers and better software, the military’s use of 3-D printing is skyrocketing. Scientists and officials involved in the services’ efforts believe that troops may one day be able to make fully-functional printed objects even while on the battlefield or onboard a ship.

Creating printed models, prototypes or simple replacement parts is only the tip of the iceberg, they said. The services are experimenting with new substances and processes that could yield entire 3-D printed systems that have circuits, power storage and logic embedded in the object itself — although the fielding of such items is decades away.

“My dream is that we could print a micro-air vehicle … [including] the electrical circuitry, the battery and everything in that micro-air vehicle, just take it out of the printer and operate it remotely,” said Jaret Riddick, leader of the Army Research Laboratory’s structural integrity and durability team in the vehicle technology directorate. He keeps a small unmanned aircraft on his desk to remind himself of that goal.

Additive manufacturing — another name for 3-D printing — is currently employed throughout many Army research facilities. Scientists are designing and constructing items such as printed parts for protective masks, holders for improvised explosive device detectors, medical prosthetics and explosives, said Army Chief Technology Officer Grace Bochenek. Researchers have also made 3-D printed batteries, antennas, fuse elements and wings for unmanned aircraft, according to the service.

In additive manufacturing, a component is built in a printer that deposits layers of plastic, metal, ceramic or other materials. Traditional manufacturing processes work the opposite way — by creating a smaller part out of a larger source material by cutting, grinding or drilling it down. 

While some of the service’s scientists are using established printing techniques to make equipment, others are hoping to push the technology even further. Army Research Laboratory scientists are at the vanguard of conducting the basic research to develop and test new materials and processes for 3-D printing, Riddick said.

“The desire here is to take this very new sort of technique, additive manufacturing or 3-D printing, that’s normally been used for prototyping, and use it to actually manufacture functioning parts,” he said. “There’s a lot that needs to be understood at the very fundamental level to actually be able to make that leap.”

The lab has experimented with writing electrical traces onto 3-D printed components to eliminate wiring and manufacturing parts with antennas built into the structure, Riddick said. Doing this currently involves a variety of additive manufacturing techniques that have to be done one at a time, but the development of new materials and processes could change that.

“What we want to do is to do that all in one process. As it is right now, those processes are separate. The materials for one process don’t necessarily work with the other process,” he said. “The materials development is for being able to do this all in one process, all in one machine and one platform with materials that are compatible and work together in an efficient manner.”

The lab is also focused on creating “multifunctional” components that can transmit, sense or receive information. One example of this would be a sprocket with embedded sensors that can detect and report damage, Riddick said. It could also be some part of a tank that can also function as an antenna.

“That means that you can get rid of the antenna that’s hanging on the outside of the vehicle, make the vehicle have less of a footprint,” he said. In that way, 3-D printing may be a way to “eliminate components that are hanging off of any vehicle, eliminate weight, eliminate parts that have to be maintained [and] reduce the maintenance burden.”

Another technology the Army has its eye on is 4-D printing, in which the configuration or internal properties of a 3-D printed part changes over time in response to environmental factors such as being exposed to water, light or extreme temperatures. 

“Smart materials” that can change their properties have already been developed for traditional manufacturing, said Riddick. The challenge is being able to develop substances for 3-D printing that can similarly respond to external stimuli.

The service in 2013 awarded  $855,000 in grant funding to three scientists from Harvard School of Engineering and Applied Sciences, the University of Illinois and the University of Pittsburgh Swanson School of Engineering to develop 4-D printing materials, according to a news release from the University of Pittsburgh.

“They are working on a 3-D printed material that will respond to light that is projected through a mast,” Riddick said. “By changing the mast so the light hits the object in different orientations or different locations, they actually hope to have a material that they can control the configuration of the material by using light.”

Ralph Nuzzo, a chemistry and materials science professor from the University of Illinois, said the 4-D printing could one day create “fabric that responds to light by changing its color, and to temperature by altering its permeability, and even to an external force by hardening its structure.”

Such materials could go a long way in solving enduring problems. For instance, the Army has agonized over the tradeoffs involved in making body armor that is both protective and lightweight. Perhaps 4-D printed body armor could provide a solution to that problem, Bochenek said.

“Armor can be so heavy and bulky, and you have to transport it,” she said. “If you had a material, and you had a capability to do [4-D printing], maybe [the armor would be] packaged differently, but when it gets into certain environmental conditions, it alters.”

The Army has deployed two 3-D printers in Afghanistan to provide soldiers with small parts on demand, and some service officials have called for more widespread distribution.

Gen. Dennis Via, commander of Army Materiel Command, said in February that printers could one day be embedded with squads, so that troops can manufacture weapons, tools or repair parts while they are in the field.

Three-D printing offers the Army a “revolutionary” way to deliver customized parts on demand, Bochenek said.

“When the Army moves its systems, you have a whole supply chain, and if you’re able to build [3-D printing] in the very forward part of battlefields, now all of a sudden you reduce all that risk,” she said. “You don’t have all of that supply chain overhead, the transportation, all of those kinds of things that go with the movement of our troops in theater.”

The Navy also is gradually expanding its use of additive manufacturing from land-based operations to experiments at sea. The service in October outfitted the USS Essex, an amphibious assault ship, with a 3-D printer, said Lt. Benjamin Kohlmann, a member of the chief of naval operations’ rapid innovation cell.

The Essex currently is undergoing shore-based maintenance but could be out to sea in a matter of months, he said. In the meantime, sailors are using the printer to design and create proof-of-concept items such as medical supplies, a cap for an oil tank and a model of the ship’s flight deck and aircraft.

The goal isn’t to create printed items that would replace existing product lines, but to provide short-term solutions when parts break onboard a ship, he said. Having a printer will also give sailors the opportunity to “play with the new technology and come up with ways it can be useful.”

In order to prepare for 3-D printing equipment coming onboard, six sailors took a three-week crash course on machine operation, including how to clean the nozzles, do minor repair work and integrate it with the computer. Sailors also learned basic computer-aided design techniques, although they can also send design ideas to a technologist who can translate them into the data needed to create a printed object.

Kohlmann was clear, however, that the use of additive manufacturing on a ship is still in its infancy. The Navy previously installed a 3-D printer on a joint high speed vessel in 2013. The Essex will employ the same testing methodology used during that deployment to collect data that will inform the service on how the motion of a ship affects 3-D printers.

So far, the crew has used the printer, which is about the size of a miniature refrigerator, about twice a week, he said. The device can only print plastic equipment, as certain metal powders are flammable.

“The shipboard experiments are useful in terms of pushing the boundaries, but I think the best applications are still going to be on land for now,” Kohlmann said. “It’s certainly in the exploratory phase right now. We’re by no means in the heart of the revolution, but I think we’re on the cusp of something great.”

Operating a 3-D printer onboard a ship will be technically and logistically challenging. Cmdr. Tyson Weinert, manager of the Coast Guard innovation program, said that it may be difficult to find available space to house 3-D printers on vessels that are already crammed with equipment.

Printers will also have to withstand the harsh maritime environment and be “subjected to the pitch, the roll, the yaw [of a ship],” he said during an April panel at the Navy League’s Sea-Air-Space Exposition.

“With these added forces ... what is the tolerance for that? So how can the printer itself react to those other forces? You can try to manage the center of gravity as best you can, try and get the safest spot with the minimal amount of movement, but what is the trade off?”

Thomas Campbell, associate director for outreach at the institute for critical technology and applied science at the Virginia Polytechnic Institute and State University, said current 3-D printers might also be vulnerable to cyber attacks.

Topics: Science and Engineering Technology, Shipbuilding