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A new kind of 3D printing uses flexible polymers that can change shape depending on temperature. Image: A 3D flower changes shape due to changes in temperature. (via MIT)

 

Making useful things with three dimensional printers has been changing a lot of design and manufacturing processes in recent years. There was the kid who made his own braces, and even 3D printed shoes given as awards at a recent athletic event. All of these objects, however, are rigid: they stay the same after the printer makes them. But recently a team of researchers have developed a technique that allows printable objects to change shape. Currently under development at MIT, microstereolithography allows 3D printers to make very precise shapes in very small sizes out of bendable materials.

 

When heated to within a certain temperature range, these materials ‘bounce back’ to their original shapes. And they can be very, very tiny-one prototype had the thickness of a human hair.

 

How do you make a tiny bendable flower? Thus far, the process is akin to using a tiny camera to scale an image down to size, then chopping the image up into different layers, like different levels of parfait. The sliced up images are then connected to a printer through a series of beams.

 

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The specific polymers used to make the product bendable are mixed during printing, using rays of ultraviolet light to catalyze the reaction. Making a tiny flower that can unfold is thus a combination of two different systems: creating a series of two dimensional images from a single three dimensional shape, and mixing polymers as the image is printed.

 

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What kind of polymers have been used? So far, pretty typical plastics-industry molecules have been used to make the bendable Eiffel Tower and flowery shapes in miniature. Because they’re used so much already, the chemistry is pretty basic: just add polymers with known elastic properties together. Scaling the process down even further could expand the applications.

 

Imagine taking a drug that was so specific it would only work at certain body temperatures, or tiny implantation devices for surgical procedures. Imagine being able to print single molecules. Making small things has never had such huge implications.

 

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