TecKnow of the day
A new Fraunhofer technique makes it possible to bend sheet glass into complex or unconventional shapes with the help of laser beams. This opens up a whole new range of potential products for architects and designers. The researchers are taking advantage of a particular attribute glass has of becoming viscous and therefore malleable when exposed to high temperatures. Precise calculations and gravity do the rest.
A laser beam moves across the surface of the glass with absolute precision, following a preprogrammed if still invisible path. Every now and then, the beam stops, changes position and moves on. The four-millimeter-thick sheet of glass is in an oven that has been preheated to just below the temperature at which glass begins to melt. The glass now starts to soften at the points the laser has heated and, thanks to gravity, the heated portions sink as if they were made of thick honey. Once the desired form has been achieved, the laser is switched off and the glass solidifies again. The result is a fascinating shape with bends featuring small radii, waves and round protrusions.
This is how lasers can be used to help bend sheet glass in a process developed by the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg imBreisgau. The whole process is based on a particular physical characteristic of the material; unlike metal, for instance, glass does not have a definitive melting point at which it liquefies. Instead, when exposed to a certain temperature range, it softens and becomes malleable.
Bending glass without a mold
Fraunhofer IWM’s laser-supported technique allows architects and also industrial designers to make use of shapes that were previously difficult and costly to produce. Here, sheet glass is shaped without the need for a bending mold to apply pressure. In this way, the new process doesn’t leave behind any unsightly marks — the flat glass surfaces remain visually undistorted.