Although 3D printers can produce a wide variety of objects, the size of each item is limited by the size of the printer. Scientists have now developed a way of getting around that limitation, using a resin that expands when heated.
The material was created by a team at the University of California, San Diego, led by David Wirth and Jonathan Pokorski. It’s used in a specific type of 3D printing known as stereolithography – this involves exposing sequential layers of a photosensitive resin to patterns of light, causing them to harden into one solid object.
When an item printed with this specific resin is subsequently heated in an oven, one volatile component of the resin turns to a gas, and bubbles up to form a polystyrene-like foam. The resulting object is up to 40 times larger in volume than the original, while still retaining its shape.
So far, the material has been used to create items such as a latticed sphere, a wind turbine that’s capable of generating a small amount of electricity (once expanded into a foam), and a toy boat – the latter can carry 20 times more weight in its expanded state, as compared to when its smaller original state.
It should be noted that for now at least, the foam is not as strong as polystyrene. That said, the scientists believe that it could still find use in applications such as buoyancy aids, airfoils, cushioning materials, or perhaps expandable habitats for astronauts.
The technology is described in a paper that was recently published in the journal ACS Applied Materials & Interfaces, plus it’s demonstrated in the following video.
Source: American Chemical Society
Expandable Foam Supersizes 3D-Printed Objects – Headline Science
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