The military has begun employing 3-D printing to make spare parts and components, but the Army is already exploring the next generation, 4-D printing.

Four-D printing “takes 3-D printing and adds a transformation dimension,” Grace Bochenek, the Army’s chief technology officer, told National Defense. The idea is that a 3-D printed component’s properties could be altered when exposed to environmental factors such as water or extreme temperatures.

Bochenek envisions body armor as one possible future application of 4-D printing. The Army has struggled over the past decade with the need to field armor that is both protective and light enough to not burden the soldier or restrict movement. Using 4-D printing, scientists could one day develop lightweight, compact body armor that is easy to store and carry, but can expand and offer full coverage.

"Armor can be so heavy and bulky, and you have to transport it,” Bochenek 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."

That kind of technology, however, is still years down the road. The Army is currently focusing on developing materials for 4-D printing, she said. Afterwards, it will have to study how best to manufacture components.

While the service has only dipped its toes into 4-D printing, it is diving into 3-D printing applications and development. Although additive manufacturing — another term used for 3-D printing — has been around since the 1980s, recent improvements in software and lasers have allowed the technology to become more widespread, Bochenek said.

Gen. Dennis Via, commander of Army Materiel Command, called 3-D printing one of the service’s most promising technologies. In the future, the Army may even have printers embedded with troops so that they can make components for tools, vehicles and weapons on demand, he said last month at the Association of the U.S. Army Winter Symposium and Exposition.

Doing so would reduce risk to soldiers deployed in foreign countries who would otherwise have to stockpile parts at a base or have them shipped from the United States, Bochenek said. “You don't have all that supply chain overhead, the transportation, all of those kinds of things that go with the movement of our troops in theater."

The Army has already deployed two printers in Afghanistan to produce small parts."It's really revolutionary because it changes the way in which we can potentially do business,” she said.

“Everybody recognizes the big potential of it,” including industry, she added. “Just the fact that you don’t have to have a certain number … of production runs to achieve cost-effective parts.”

Additive manufacturing is currently used throughout many of the service’s research facilities. For example, scientists from the Edgewood Chemical Biological Center at Aberdeen Proving Ground, Md., are printing parts for protective masks and holders for improvised explosive device detectors, Bochenek said. The Army’s medical community is experimenting with printing prosthetics.

Its armament research, development and engineering center headquartered at Picatinny Arsenal, N.J., is looking into using it to make explosives, she said. That facility also has employed 3-D printing to make batteries, antennas, fuze elements and wings for unmanned aircraft, according to the Army.

At the same time, the service is refining 3-D printing processes and techniques, Bochenek said. “We have to be able to increase the part sizes, and we have to be able to increase the speed of the ability to do this and the kinds of materials we use."

Army scientists and engineers informally share information on additive manufacturing, but Bochenek is looking at ways to standardize that process. One option is to create virtual labs where researchers could manage their own technical and modeling data, simulations and business information and connect to other Army scientists.

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