ABERDEEN PROVING GROUND, Md. — Army scientists are on the brink of a pioneering additive-manufacturing technology to help Soldiers quickly swap out broken plastic components with durable 3D printed replacements, says a top Army researcher.

In the past, troops have either lugged replacement parts around or ordered them from warehouses thousands of miles away, only to wait weeks for them to arrive.

But with dual-polymer 3D printed parts — developed by scientists at the U.S. Army Combat Capabilities Development Command Army Research Laboratory, or ARL — Soldiers could be a few clicks away from swapping out broken pieces and heading back to the fight within hours.

“We’re crossing a threshold where low-cost, easy-to-operate and maintain printers will be proliferated on the battlefield — and able to produce engineering parts of very good quality with short turn-around times,” said Dr. Eric Wetzel, ARL’s research arealeader for Soldier materials.

“In order to do that, we need printing technologies that can print parts that are accurate geometrically and have mechanical properties that are sufficiently robust to survive conditions in battle,” he added.

The printing technology comes on the heels of Secretary of the Army Ryan McCarthy pushing an advanced manufacturing policy last October, intended to enhance supply chains in the field.

Until this point, 3D printing technologies that produce mechanically robust parts have required printers and print technologies that are not suitable for austere environments, while the printers suitable for austere environments produced poor-quality parts, Wetzel said.

That’s where the ARL scientists come in. For the last few years, they have delved into this issue, Wetzel said. For the first time, ARL scientists have developed a cutting-edge filament capable of being used in off-the-shelf, low-cost 3D printers to produce mechanically strong, battlefield-ready parts.

“By summer, we hope to have samples of the filament distributed to Army transition partners,” Wetzel added. Based on their feedback, ARL could ramp up production — with help from industry partners — and have it in the hands of Soldiers within the calendar year.

THE DUAL-POLYMER TECHNOLOGY

“Conventional polymer filaments for 3D printing are made up of a single polymer,” Wetzel said. “Our innovation is that we’ve combined two different polymers into a single filament, providing a unique combination of characteristics useful for printing and building strength.”

The dual-polymer filament combines acrylonitrile butadiene styrene, or ABS, with polycarbonate, or PC. A critical design feature of the filament is that the ABS and PC phases are not simply mixed together, a common approach for creating blended polymers. Instead, a special die-less thermal drawing process developed by ARL is used to create an ABS filament with a star-shaped PC core. Once coupled, the filament is used as feedstock in a desktop fused-filament fabrication, or FFF, printer to create 3D prints with a heavy-duty ABS/PC meso?structure.

FFF printers work with a heated nozzle that emits thin layers of melted plastic, similar to molten glass. The filament is deposited onto a print bed, one layer on top of another until it forms the 3D printed part. In order to fabricate a unique part, the nozzle, print bed, or both move while the hot plastic streams down.

The two polymers found in the new filament technology have distinct melting temperatures, Wetzel said.

After the solid bodies are initially printed, they are put in an oven to build strength. During this annealing process, the deposited material layers fuse together while maintaining their geometry and form. This stability is caused by the higher temperature resistance of the built-in framework.

“The second polymer holds the shape like a skeleton while the rest of it is melting and bonding together,” Wetzel said. “Through a series of filament design trials, we were able to identify that the star-shaped PC core provided a superior combination of part toughness and stability compared to other arrangements of ABS and PC in the filament.”

Current filaments — traditionally consisting of a single thermoplastic — produce parts that are brittle and weak, and would deform excessively during the annealing process, he said.

“We focused in on what can we do to improve those mechanical properties,” he added. “We wrote a series of papers getting very fundamentally down to the details of exactly why conventional single-polymer parts are not sufficient, what’s happening in the physics of the polymer — really at a molecular level — that prevents conventional printed polymer parts from meeting these requirements.”

The legacy thermoplastic deposits like a hot glue gun, he said. As the layers build, they don’t stick very well to the previous layer because by the time the second layer adds, the first one is cooled off.

“So, you’re not melting the layers together, you’re just solidifying material on top of one another, and they never really bond between layers,” Wetzel said. “Our technology is an approach that allows us to use these conventional desktop printers, but then apply post-processing to dramatically improve the toughness and strength between layers.”

“Manufacturing at the point-of-need provides some exciting possibilities,” Wetzel said. “In the future we can imagine Soldiers deployed overseas collaborating with engineers in the United States, allowing new hardware concepts to be designed and then sent as digital files to be coverted into physical prototypes that the Soldiers can use the same day. This paradigm shift could allow us to innovate at a much higher speed, and be keenly responsive to the ever-changing battlefield.”

Story by Thomas Brading, Army News Service

Photos by EJ Hersom

RESEARCH TRIANGLE PARK, N.C. (Dec. 19, 2019) –  Researchers working on an Army-funded project have developed an algorithm to simulate how electromagnetic waves interact with materials in devices to create equipment more efficiently and accurately. The algorithm could be used in a wide range of fields – from biology and astronomy to military applications and telecommunications.

Electromagnetic waves exist as radiation of energies from charges and other quantum processes. They include radio waves, microwaves, light and X-rays. Mobile phones communicate by transmitting radio waves.

It takes a tremendous amount of computer simulations to create a device like an MRI scanner that images the brain by detecting electromagnetic waves propagating through tissue. Those simulations can take days or months to identify how the electromagnetic waves will react when they encounter the materials in the device. Because of the cost, there is a limit to the number of simulations typically done for these devices.

With funding from the Army Research Office, in a study, published in the SIAM Journal on Scientific Computing, SMU (Southern Methodist University) researchers revealed a faster algorithm for these simulations. It is a more efficient and less expensive way to predict the behavior of waves.

“We can reduce the simulation time from one month, to maybe one hour,” said lead researcher Wei Cai, SMU Clements Chair of applied mathematics. “We have made a breakthrough in these algorithms.”

“Electromagnetic waves are central to many important applications in sensing, power, and communication. Being able to conduct related simulations faster and less expensively will have many military applications,” said Dr. Joseph Myers, Army Research Office Mathematical Sciences Division chief. ARL is an element of the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory. “For example, this work will help create a virtual laboratory for scientists to simulate and explore quantum dot solar cells, which could produce extremely small, efficient and lightweight solar military equipment.”

The new algorithm modifies a mathematical method called the fast multipole method, or FMM, which was considered one of the top 10 algorithms in the 20th century.

Using this new algorithm, the computer simulations map out how materials in a device like semiconductor materials will interact with light, in turn giving a sense of what a particular wave will do when it comes in contact with that device.

An engineer or mathematician would be able to use this new algorithm to test a device whose job is to pick out a certain electromagnetic wave. For instance, it could be used to test designs for a solar light battery that lasts longer and is smaller than currently exists.

“To design a battery that is small in size, you need to optimize the material so that you can get the maximum conversion rate from the light energy to electricity,” Cai said. “An engineer could find that maximum conversion rate by going through simulations faster with this algorithm.”

The algorithm could also help an engineer design a seismic monitor to predict earthquakes by tracking elastic waves in the earth, Cai noted.

“These are all waves, and our method applies for different kinds of waves,” he said. “There are a wide range of applications with what we have developed.”

The computational system used for this project, the SMU MANEFRAME II, is descended from the Army high-performance computing system “Mana,” formerly located at the Maui HPC Center in Hawaii, and donated and physically moved to SMU through the efforts of ARO and SMU.

By US Army CCDC Army Research Laboratory Public Affairs

ARLINGTON, Va. — The Army’s advanced manufacturing push intends to cut production timelines and costs throughout the lifecycle of systems, said an Army acquisition officer.

“Can you imagine how great it would be if we could just not have any parts in the logistics system, only raw materials, and we would just print the part at the point of need, right?” asked Maj. Gen. David Bassett, program executive officer for Command, Control, and Communications – Tactical, or C3T, during a panel discussion Wednesday.

That vision has become synonymous with advanced manufacturing, he said during the Association of the U.S. Army’s “Hot Topic” forum on Acquisition and Contracting.

Advanced manufacturing forges innovative technologies to “create new, or improved products or processes,” said Paul Mehney, C3T public communications director.

One technique, additive manufacturing, incorporates 3D printing, robotics, artificial intelligence and composite materials. But according to Bassett, that’s just a fraction of what the new push entails.

Over the last several months, C3T project managers have partnered up with the members of the Army’s Command, Control, Computers, Communications, Cyber, Intelligence, Surveillance and Reconnaissance Center — known as the C5ISR — at Aberdeen Proving Ground in Maryland and applied 3D printing techniques for network integration efforts.

At the proving ground, they have been prototyping radio, gateway and server racks, and mounting brackets on lightweight military vehicles to support network enhancement efforts of the Integrated Visual Augmentation System.

“The use of 3D printing enables developers to experiment with form/fit/function of different mounting systems and also allows developers and integrators to quickly incorporate Soldier feedback,” Mehney said.

To enable network connectivity for the Integrated Visual Augmentation System, developers are prototyping an integrated network enhancement kit called the Bloodhound, Mehney said.

Bloodhound is a network communications gateway and data management kit currently integrated onto light vehicles — but it is platform agnostic, he said, meaning it runs equally well on more than one platform.

During recent IVAS Soldier Touchpoint experimentation, infantry Soldiers and Marines provided feedback on the location of network systems on the Bloodhound, and made suggestions to improve form and fit of integrated network components.

“Future IVAS network capabilities may include data synchronization over narrow band SATCOM [Satellite Communications] with up to 75% reduction in component payload size, which will allow for network kit integration into combat and tactical vehicle platforms,” Mehney said.

IVAS network capability integration on the Stryker and Bradley platforms are both already in motion.

“3D manufacturing techniques will allow additional prototypes to be made as more Soldier feedback in development and operations is received, and as additional vehicle platforms are identified for network kit integration,” Mehney said.

Last month, the U.S. Army Combat Capabilities Development Command Soldier Center, in partnership with the University of Maine, procured the world’s largest 3D printer, to further bolster collaboration with industry leaders.

The printer will enable the rapid creation of large products for the Soldier, said Professor Habib Joseph Dagher, Advanced Structures and Composites Center executive director at the college.

Once a design configuration is locked, design plans developed out of advanced manufacturing techniques will be handed to industry for production.

Although the Army fostering of advanced manufacturing methods and materials are in its early stages, the service’s industrial base “must rapidly innovate to keep pace with industry and adversaries exploiting” their own advanced methods and materials, according to an Army statement.

But digital engineering is only the start, Bassett said. “Techniques [with advanced manufacturing] are now available to us that should aid in efficiency, and allow us to build things we never could have envisioned.”

In other words, 3D printing is only a part of advanced manufacturing and it “looks across the entire lifecycle of the system, starting with design, manufacturing and sustainment,” Bassett said.

“If you start to build a system this way,” he said, “when you get to sustainment, you should be able to identify what parts you can manufacture in different ways.”

The Army’s new manufacturing policy is made up of three elements: strategic investment, systematic adoption, and deliberate and thoughtful use, said Brian Raftery, acting deputy assistant secretary of the Army for strategy and acquisition.

Strategic investment must “develop a holistic, threat-based strategy for the investment in and use of advanced methods and materials” and open the door for outside partnership with industry leaders, he added.

The second principle integrates advanced manufacturing technology upfront, and throughout the system’s lifecycle, Raftery said.

And lastly, advanced manufacturing will be deliberate and used thoughtfully, he said. This means it will keep in mind aspects of things like return on investment and intellectual property implications.

Story by Thomas Brading

First photo by SSG Armando R. Limon