SkyscraperPage Forum - How To Bend Flat Glass Perfectly Around Corners

How To Bend Flat Glass Perfectly Around Corners

1.10.2019

Read More: https://www.iwm.fraunhofer.de/en/pre...d_corners.html

Quote:

Researchers from the Fraunhofer Institute for Mechanics of Materials IWM have developed a new process that can bend sheets of glass to produce angular corners. Unlike conventional processes, this does not impair the optical properties of the glass. Bent glass looks destined to play a key role in future building design, and there are also potential applications in the fields of medical technology and industrial design.

- Smart office blocks and apartment buildings feature windows that wrap around the corners of the structure. To achieve this, window manufacturers join two panes of glass at an angle, using either a metal profile or an adhesive bond. Now, however, researchers from the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg have developed a spectacular way of bending sheets of glass – to angles of 90°, for example – so that the corner thereby produced is sharp and angular. In other words, they have made the corner an integral part of a single sheet of glass.

- “We’ve already had lots of positive feedback from architects,” says Tobias Rist, a specialist in glass forming at Fraunhofer IWM and head of the Glass Forming and Machining group. “A lot of them are now keen to know when this corner glass will be available. But our lab system only processes sheets of glass one square meter in size, so we’re only able to produce prototypes.” The research team is therefore eager to join forces with partners and scale up the process to produce larger formats.

- Current technology, however, is incapable of producing narrow curvatures or a clean-edged bend of 90°. What’s more, conventional processes often impair the optical properties of the glass. In order to bend a sheet of glass, it is placed in a metal mold and then reheated. This renders the glass soft and malleable, so that it can be shaped according to the contours of the mold. This can cause the glass to deform at the contact points with the support. So once the glass has cooled down, faint imprints remain that are visible when inspected at close range. Moreover, the molding process causes corrugations to form on the surface of the glass, with the result that light is no longer reflected uniformly.

- The team from Fraunhofer IWM has circumvented this problem by developing their own kiln. Instead of heating the entire sheet of glass until it becomes soft, only the area of the glass where the actual bending is to take place is heated to that point. This is done by means of a laser and mirrors, which guide the powerful beam along the bend line. The kiln is heated to around 500° Celsius, just below the so-called glass transition temperature, at which point glass becomes soft. “And then the laser only has to heat the glass at the relevant area by a few more degrees until it reaches the glass transition temperature, and we are able to bend it,” Rist explains. In this case, bending is accomplished by means of gravity.

- According to Rist, there are potential applications in many other areas apart from architecture as well – including industrial design. For example, this technique could be used to cover household appliances with a continuous sheath of glass, instead of the usual combination of plastic and metal sheets. This glass skin would extend down from the top to the angled front of the appliance, without gaps or joints, and cover a touchscreen control panel. Such a design would be not only highly attractive but also simple to clean on account of the gap-free surface. For reasons of hygiene, glass is also an ideal material for the manufacture of medical equipment. Steel, by contrast, is relatively easy to scratch.

.....

https://i.imgur.com/COTu1v1.jpg?1