Glassmaking is one of the world’s oldest arts. Ancient Mesopotamians and Egyptians made glass glazes more than 5,000 years ago, and glassblowing was developed in the early days of the Roman Empire.
Since the mid-1900s, glass has been made in factories by melting sand, then floating sheets of it in vats of molten tin (or, you know, as a byproduct of testing atomic bombs in the desert).
Researchers now hope to make glass with a more versatile, modern-day technology: 3-D printing. In a study published in Nature on Wednesday, a team from Germany presented a new glassmaking method based on a “liquid glass” that can be shaped into complex structures with a 3-D printer, and then heated into a solid. The technique may reduce the time and costs of creating complex or detailed glass pieces, and yield high-quality glass that is smooth enough to make lenses and mirrors, said Bastian Rapp, a principal investigator at the Karlsruhe Institute of Technology, and an author of the paper.
Three-dimensional printing is more pervasive than ever, yet it remains mostly limited to plastics, ceramics and metals. People thought glass would just not be accessible to 3-D printing, Dr. Rapp said. “We wanted to close this important material gap.”
Other groups have 3-D-printed glass, including an Israeli company called Micron3DP and a group led by Neri Oxman at M.I.T.’s Media Lab. But Dr. Rapp’s approach is different, according to Michael Petch, editor in chief of the website 3D Printing Industry. The other two approaches involve melting and laying down strands of material, sort of as you would with a glue gun. Extruding the glass in layers makes it difficult to create a smooth, transparent object, Mr. Petch said.
Dr. Rapp’s team used a method called stereolithography, which involves shaping structures with UV light. They loaded a high concentration of glass nanoparticles into what’s called a photocurable liquid, which hardens under UV light. The mixture sits in a container and is exposed, slice by slice, to UV light that has been programmed to create different shapes at each layer. The regions that are exposed become solid. Heating the structure in a high-temperature furnace, like a ceramics kiln, burns away the leftover liquid and fuses the glass nanoparticles together.
Creating unique or intricate glass shapes this way has the potential to be much easier, and orders of magnitude cheaper, than the methods commonly used today, Dr. Rapp said. Currently, shaping large glass structures involves exhaustive melting and casting processes, and etching fine features involves hazardous chemicals. With this method, you upload your 3-D design, and “the software does all the rest,” he said.
Potential applications are manifold, from creating skyscraper facades to making tiny devices for chemistry research, according to Dr. Rapp. Since final products are clear and reflective enough for optical applications, the technology might one day be used to make camera lenses for smartphones or components for light-based computing.
People might even be able to design their own glass products at home. “Maybe, in the future, if you drop a drinking glass, you could 3-D-print a new one,” Dr. Rapp said.
Dr. Oxman, at M.I.T., praised the new study as “the most detailed demonstration we have seen of the stereolithography technology” with glass. So far, she said, Dr. Rapp’s team has demonstrated that the technology works at small scales, on the scale of centimeters — not necessarily the large, architectural scales her team is targeting.
But over all, she said, “this work demonstrates a leap in the right direction.”