October 26, 2012
New Method Allows Safety Glass To Be Cut To Any Shape
Shock-resistance is the great benefit of safety glass. However, the cut of the glass pane can make this difficult: With conventional processes, only straight cuts are possible. Yet a newly-developed method makes it possible to apply any cutting technique. Researchers will display an undulating-cut pane of safety glass at the Glasstec trade fair from 23 to 26 October in DÃ¼sseldorf (Hall 15, Booth E25).
If architects want extravagantly shaped windows, like round ones, the standard practice is for the safety glass panes to be carved and detached by hand. However, the resulting gap is too small to allow enough space for a knife, which could also inadvertently sever the film. To widen the gap, and ultimately to be able to cut the desired form, the film is softened with heat by applying alcohol and setting it alight. A new method will soon be able to circumvent this dangerous procedure. Researchers at the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, working jointly with Hegla, have engineered a new process. “We cut the interior film before the glass is scored and broken apart,” explains Tobias Rist, scientist at Fraunhofer IWM. “We use a laser beam that can be guided over the pane as desired. This is why we are also able to cut unusual geometries.” The laser beam penetrates the glass and releases its energy primarily in the film. The film gets hot enough for it to melt and vaporize. With this method a channel is produced in the film, and the film is separated locally. When the film is “cut,” the glass is carved and fractured parallel to the resulting film channel. “The process can be readily automated and applied on an industrial scale,” says Rist.
Researchers will exhibit safety glass that features an undulating dividing line at the Glasstec trade fair from 23 to 26 October in DÃ¼sseldorf (Hall 15, Booth E25). The laser process is operationally ready; Hegla will integrate it into a new laminated safety-glass pattern cutting system, and optimize it for industrial use. Hegla has already been granted a German and a European patent for the process of carving contours. The researchers are now working on another step that will make the process even faster, thereby increasing clock speed.
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