Glass as a building material has a plethora of benefits—natural lighting, rust resistance, soundproofing and more—but its flat nature requires additional materials to connect pieces, which means potential weak spots when it’s wrapped around corners. Researchers from the Fraunhofer Institute for Mechanics of Materials IWM have changed all that thanks to the development of a process that allows glass to be bent, resulting in angular corners that are part of the glass.
There is existing technology that allows for smaller radii bends of glass. It requires placing sheets of glass in a metal mold to be reheated so it is can then be reshaped. Along with creating the potential for deformities in the glass, including improper light reflection, the technology is unable to create 90-degree bends. The Fraunhofer team got around that problem by developing its own unique kiln and laser process that creates precise angles up to 90 degrees.
“We now know how to control the laser in order to bend glass of the required thickness to achieve the exact angle, or bend radius, we want,” said Tobias Rist, a specialist in glass forming at Fraunhofer IWM and head of the Glass Forming and Machining group. “We’re the first to be able to produce a 90-degree bend like this. Architects who’ve seen the results are really excited.”
The kiln the team created allows for heating only the part of the glass that will be bent instead of the entire sheet using lasers and mirrors along the bend line. The kiln heats to the optimal temperature for bending at 500°C. The actual bending uses the basic force of gravity. During the bending process, the sheet of glass is supported and only inserted into the kiln where the bend will occur. After the laser does its work and the glass softens, gravity creates the perfect bend. The process leaves the glass aesthetically intact and smooth.
While that may sound easy enough, getting to that point required developing intricate process models to determine the speed at which the laser needed to move to bend at the precise moment of glass softness. The researchers also had to calculate how fast the laser’s heat penetrated the glass, as well as how quickly it laterally spread.
After some experimenting, the researchers determined that the laser could be used on a series of sheets, resulting in the production of sandwich structures and the creation of laminated safety and insulating glass. This has potential uses that extend beyond building material and into areas like manufacturing, such as with appliance covers. The medical arena is also a viable area for its use, especially since the need for hygienic materials is vital in the industry.
“Using our process, it would be possible to produce a single glass sheath to cover the top and sides of such equipment,” Rist said. “And this would also avoid any edges or joints where germs could build up.”
While the researchers’ work is beginning to garner significant interest, the lab only has the capacity to complete bends for prototypes on glass sheets that are 1 square meter.
Along with finding new techniques to better use existing materials in buildings, many others are focused on incorporating new materials or methods. To learn more, check out Not Just a Pipe Dream: Hemp as a Building Material and Engineering Fabric Buildings: Speed, Permanence and Cost Savings.