March 16, 2012
-- The ability to generate tiny three-dimensional objects using a special printer just got a whole lot faster. Machines, known as two-photon lithography printers, can produce detailed structures as small as a grain of sand. Vienna University of Technology researchers Jan Torgersen and Peter Gruber, led by materials science and technology professor Jürgen Stampfl, took the printing process from millimeters per second to five meters per second, a world record. This 3-D printed version of St. Stephan's Cathedral in Vienna is about 50 micrometers wide on its largest side, smaller than the diameter of the average human hair.
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The printing process works by focusing a laser beam onto liquid resin. Mirrors guide the beam to solidify lines of the resin into solid polymer. Line by line, a layer is built. Each structure consists of numerous layers. The scientists use a new resin, developed by chemistry professor Robert Liska, that could be solidified anywhere, not just on top of the previous layer. They also used faster electronics and rotating mirrors that had improved steering. This is a 3D image of the "Wormser Tor," the city gate leading into the historic German town Frankenthal, which was first settled in the 8th century. The scientists designed it from original photographs and their resulting print has never been published until now, Torgersen told Discovery News.
This race car is about 285 micrometers wide, according to Torgersen. While still small, it's several times the width of a human hair. In the field of two-photon lithography printing, he calls their record-breaking printer a significant step closer to real applications and commercialization.
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The goal was to speed up the process in order to make this type of printing more attractive as a technique, as well as more cost-effective. Usually the speedy printer was occupied with the scientists' experiments instead of producing recognizable images, Torgersen said. But they did have some fun in demonstrating its capabilities, like this image of a man. Tiny, intricately printed 3-D structures could have a number of different applications. For example, they could be used in medicine to make scaffold for living cells in order to build tissue.
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Here, they replicated the Tower Bridge in London. Torgersen said he and his colleagues plan to focus on water-based biopolymers for biological applications. They currently have a paper on using hydrogels for the printing process under revision. "We hope we can motivate potential partners from the biology side to work with us," he said.
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Jan Torgersen and Peter Gruber Researchers Jan Torgersen (left) and Peter Gruber (right) stand next to the printer. The printer is part of a project called Phocam to develop new 3-D printing technology with industry partners.
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