The morphing nozzle in action, 3D printing fiber-filled composites with on-demand control of fiber orientation (Credit: University of Maryland)
A new shape-changing 3D printer nozzle could enable complex new creations with unique material properties, according to the developers.
Engineers at the University of Maryland (UMD) developed the Morphing Nozzle, which opens up new possibilities for printing fiber-filled composites. The materials consist of short fibers that improve the properties over conventional printed parts, such as B. improved strength or electrical conductivity.
The challenge, according to the researchers, is that these properties are based on the orientations of the short fibers – something that was previously difficult to control during the printing process.
“In 3D printing with the morphing nozzle, the force lies in its side actuators, which can be inflated like a balloon to change the shape of the nozzle and thus the orientation of the fibers,” said Ryan Sochol, mechanical engineer at UMD.
To demonstrate their new approach, researchers focused on 4D printing applications – the creation of 3D printed objects that can be reshaped or transformed depending on the environment.
“In our work we examined how printed parts swell when immersed in water and whether we can change this swelling behavior with the help of our morphing nozzle,” said co-author David Bigio.
Recent advances in 4D printing have relied on materials that have both “anisotropic” expansion – swelling more in one direction than another – and “isotropic” expansion that swells identically in all directions. However, to switch between these conditions, researchers typically had to print with several different materials.
“It was exciting to discover that we can transition a single print material between anisotropic and isotropic swell by simply changing the shape of the nozzle during the 3D printing process,” said lead author Connor Armstrong.
“Importantly, the nozzle’s ability to transform and equalize the score for swell properties is not limited to 4D printing,” said co-author Noah Todd. “Our approach could be used for 3D printing of many other composite materials in order to adapt their elastic, thermal, magnetic or electrical properties.”
To build the morphing nozzle themselves, the team used a different 3D printing technology known as polyjet printing. This multi-material, inkjet-based approach allowed researchers to 3D print their nozzle with flexible materials for the inflatable side actuators and shape-changing center channel, as well as rigid materials for the outer housing and access ports.
The team is investigating the use of the new technique to print in large quantities biomedical objects that could change shape in the body. The team is also in talks with the Department of Defense about using the morphing nozzle to aid weapons production.
The research was published in Advanced Materials Technologies.
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