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You can now 3D print a tiny pretzel made of glass

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Not for eating

3D printing with "liquid glass"

Scientists are using "liquid glass" to 3D print tiny, intricate objects.

Posted by The Verge on Wednesday, April 19, 2017

Scientists in Germany have 3D printed very intricate tiny objects using glass. And of course, one of these objects is a pretzel. In the future, the technique could be used to 3D print more useful things, like complex lenses, filters, and even ornaments that generally need highly skilled artisans to make.

The researchers used a type of “liquid glass” to make complex shapes that are smooth, transparent, and have a very high resolution, according to a study published today in Nature. More importantly, the glass objects were created using standard and commonly used 3D printers. The technique, however, also requires the use of a high-temperature oven you’re not likely to have in your apartment for baking a pie. Regardless, the study opens up the possibility of making an extremely important material accessible to one of the most revolutionizing technologies of our time.

A 3D printed castle gate made by the German researchers

Today, 3D printers are used to make all sorts of things — from shoes to airplane parts — with a variety of materials, usually plastics but also metal and ceramic. Glass has some pretty unique properties — it’s hard, long-lasting, can insulate against heat and electricity, and is key for creating the highest quality lenses for anything from your glasses to your camera. But the material is hard to 3D print because it melts at extremely high temperatures.

“Glass is one of the oldest materials known to mankind,” says study co-author Bastian Rapp of the Karlsruhe Institute of Technology, “and it has been pretty much ignored in the 3D printing revolution of the 21st century.”

Scientists have 3D printed glass before. Scientists at MIT have made transparent glass objects using a special 3D printer that heats up to about 1,900 degrees Fahrenheit. Other attempts have resulted in mostly weak and cloudy glass objects. The technique described in today’s study is different because it uses 3D printing technology that’s already widely available, Rapp says.

The special sauce is in the material Rapp and his team used. The “liquid glass” they designed is a glass powder embedded into a liquid polymer. Here’s how it works: a standard 3D printer uses the liquid glass to print an object. The object is then processed in a high-temperature oven where the glass particles fuse together, becoming transparent. The technique was used to make objects like a castle gate, a pretzel, and a honeycomb structure that are a few millimeters in size, and have features as small as a few tens of micrometers. (The resolution, however, can be even higher by using a higher-resolution 3D printer.) The objects could also withstand temperatures as high as 1,472 degrees Fahrenheit.

This “allows us to process one of the oldest material with some of the most astonishing optical, mechanical, and physical properties by state of the art modern 3D printing instruments,” Rapp says. “Our aim was to close this material gap.”

A 3D printed glass honeycomb can withstand temperatures as high as 1,472 degrees Fahrenheit

In the future, this technique could be used to 3D print complex lenses for things like smartphone cameras, and parts for next-generation microprocessors, Rapp says. But the applications are really limitless — from glass ornaments to intricate glass panels used in buildings.

I just hope 3D printing won’t actually replace the traditional glass blowing techniques mastered in places like Murano, Italy. I always get a kick out of seeing those sweaty glass blowers moulding the scorching hot, orange material. I’m pretty sure a 3D printer isn’t as artistic!