The U.S. Army just unveiled a new type of multipolymer filament for commonly used 3D printers for desktop material extrusion. The new material could be used to make critical parts with higher performance when needed.
Parts made with simple FFF 3D printers have historically had poor strength and toughness, which has prevented affordable printers from being used to supply military parts on-demand, especially on-site. The Army’s new material overcomes these shortcomings and potentially enables soldiers to use inexpensive printers to produce parts that, after a few hours of heat, can achieve mechanical properties robust enough to withstand harsh field operations.
This breakthrough is an important step forward in the Army’s expedition manufacturing, said Dr. Eric D. Wetzel, who leads the Emerging Composites team and serves as research director for soldier materials in the Army Research Laboratory of the US Army Combat Capabilities Development Command. Wetzel’s research encompasses a wide range of technological solutions that can increase the lethality of soldiers by improving the way warfighters fire, move, communicate, protect, and maintain themselves.
“The army wants to be able to print parts on site to simplify logistics by carrying digital parts files instead of physical parts. Until now, however, the technologies for manufacturing high-strength parts in expeditionary environments have not been practical. These printers are too big to start with, power hungry, fragile, or messy, and their raw materials can have special memory requirements. “This technology can enable the army to use inexpensive, simple printers to make high quality parts.
According to the paper, making molten filaments, or FFF, is the most common additive manufacturing technology, but parts made using FFF do not have sufficient mechanical integrity for most engineering applications. The research team used a novel thermal drawing process to create a two-material filament containing acrylonitrile-butadiene-styrene, known as ABS, with a star-shaped polycarbonate core.
This two-material filament is then used as a feedstock in a conventional FFF printer to create 3-D solids with a composite ABS / polycarbonate core mesostructure. This novel DM filament can revolutionize additive manufacturing and allow low-cost printers to produce parts with mechanical properties that compete with injection molded plastics, as stated in the paper.
In ongoing experiments, the army’s research team is experimenting with new material pairings, pressure conditions and annealing protocols in order to further improve mechanical properties and shorten processing times. Your goal is to reduce the current glow times from 24 to 48 hours to four hours or less.
Researchers are using a pilot manufacturing line to manufacture larger quantities of the filament over the next few months and provide material samples for a variety of army’s transition partners.
“The ability to additively manufacture parts from a high-strength polymer using the FFF process at field, division and / or depot level certainly offers warfighters the opportunity to produce better temporary parts much faster – hours compared to days or weeks. and at a significantly lower cost – often pennies compared to ten dollars, said Jeff Wallace, a mechanical engineer with the Army’s C5ISR center at APG. “Soldiers also improvise as needed and often find their own design solutions to the problems they face. Offering a higher strength polymer material to use in the desktop printers they have access to gives them the ability to innovate on the fly to temporarily solve a larger number of delivery and design issues. Your designs would then be sent to the appropriate engineering support activity for evaluation. “
The lab has filed several patent applications for the technology, and one aspect of the technology has already been licensed: thermally drawn filaments using a specialty polymer for use in additive manufacturing. The Army is looking for additional trading partners to accelerate the development and deployment of this technology, which could have broad applicability to a wide range of additively manufactured thermoplastic parts.