3D printing is a cool and multi-purpose technology that has countless applications. However, so far, it has been limited by one thing, and that is the size of the 3D printer.
That may soon change. A team from UC San Diego has developed a foam that can expand to up to 40 times its original size.
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"In modern manufacturing, it is a widely accepted limitation that the parts patterned by an additive or subtractive manufacturing process (i.e., a lathe, mill, or 3D printer) must be smaller than the machine itself that produced them. Once such parts are manufactured, they can be postprocessed, fastened together, welded, or adhesively bonded to form larger structures." reads the study's abstract.
"We have developed a foaming prepolymer resin for lithographic additive manufacturing, which can be expanded after printing to produce parts up to 40× larger than their original volume. This allows for the fabrication of structures significantly larger than the build volume of the 3D printer that produced them."
The team began by selecting a monomer that would act as the building block for the polymer resin: 2-hydroxyethyl methacrylate. Next, they had to find the optimal photoinitiator concentration along with an appropriate blowing agent to pair the 2-hydroxyethyl methacrylate to. After several tests, the team settled on a non-traditional blowing agent typically used with polystyrene-like polymers.
Once they finally had the final photopolymer resin, the team tested 3D printing a few simple CAD designs and heating them at 200°C for up to ten minutes. The end result revealed structures that had expanded by up to 4000%.
The researchers believe this technology could now be used for lightweight applications, such as aerofoils or buoyancy aids, as well as in aerospace, energy, architecture, and biomedicine. The study is published in ACS Applied Materials & Interface.