While consumer 3D printers are great for making models or curios, they’re not always up to the task of creating objects that will withstand real-world use. However, this could change thanks to a new pressure thread.
Compact, inexpensive 3D printers typically use a process known as Fused Filament Fabrication (FFF). A plastic thread is heated to its melting point and then extruded through a nozzle. Successive layers of the molten plastic are deposited on top of one another and form a single solid object when they cool and fuse together.
However, according to US Army engineers, items printed in this way tend to be too structurally weak to be used tough and tough by soldiers in the field. This is a shame because if troops could carry small, cheap 3D printers, they could make parts and tools on-site if needed. And while there are printers that use non-FFF techniques to make stronger objects, these machines are large and expensive, making them impractical for field use.
Under the direction of Dr. Eric D. Wetzel, researchers from the Army’s Emerging Composites Team set out to address this problem. Ultimately, they developed a new dual-polymer filament that would allow consumer 3D printers to make much stronger items using their existing FFF hardware.
The material begins in the form of a cylinder with a star-shaped polycarbonate core which is surrounded on all sides by ABS (acrylonitrile butadiene styrene). Using a proprietary device called a thermal draw tower, this cylinder is heated and drawn out into a thin filament.
Once the filament has cooled, it can be wound onto a roll and then used in a standard FFF 3D printer. Items printed from the material are then heated in an oven and then cooled to ensure that the two polymers fuse together thoroughly.
In laboratory tests, such objects were found to be much stronger than those made from conventional filaments – in fact, they exhibited mechanical properties similar to identical objects made using commercial injection molding techniques. The material’s glow time (heat up and cool down) is currently 24 to 48 hours, but the team hopes to reduce that number to four hours or less.
The army is now looking for industrial partners who might be interested in commercializing the technology in order to use it beyond military applications.
An article on the filament was recently published in the journal Advanced Engineering Materials.
Source: US Army Research Laboratory