Laser technology
� The laser beam edge of Corning’s 3D laser. Image: Corning.
Lasers add value in the glass industry At its recent online conference, VDMA* discussed how laser technologies create added value in glass production. Companies such as Schott and Saint-Gobain presented their applications.
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oday, mechanical processes are reaching their limits when it comes to many glass products. Precision cutting, drilling, coating, melting and texturing advanced specialist glass are now all performed by lasers. Having previously taken a critical view, today the glass industry simply could not function without lasers in modern production. Being low-maintenance and cost-efficient, laser technology is also economically attractive. One example is when processing ultrathin glass for displays: this glass often has tiny cut-outs that cannot be cut using mechanical means. To allow noticeable improvement in mobile reception inside buildings, lasers help to break up coated insulating glass units with finely drawn patterns, without any significant change to how the glass looks. Lasers even enable thermal processes: glass coatings can be heated to hundreds of degrees and thus changed, without subjecting the glass itself to these temperatures. This technology offers
enormous benefits when it comes to processing thermally tempered glass in particular. Using laser technology allows processors to save CO2 or even, where alternative energies are used, eliminate its use altogether. This is because there is no need for energy-intensive treatment of process water following additional grinding, nor for producing cutting and separation equipment with high levels of material wear. VDMA’s industrial working group Research & Technology dedicated its most recent meeting to the topic, with various companies presenting their applications.
Automotive Flabeg Automotive Germany from Furth im Wald offers solutions for glass and mirror applications in glass finishing, using lasers for cutting and drilling. Laser cutting has two stages. First, the line to be cut is perforated. Then a crack is drawn along the perforation so that the glass can be split off. Stacking the filaments on top
of each other makes this process possible up to a glass thickness of 12 millimetres and a speed of up to 500 mm/s, although only for flat glass. Laser drilling, on the other hand, has just a single stage in which the laser focus is guided through the glass thickness. This process offers more design options for the glass, such as where it is slightly curved. In both processes, the energy input comes from non-linear processes. This causes structural changes to the glass, highly localised in terms of both space and time, so that the glass is not impaired outside the focus.
Saint-Gobain The Saint-Gobain Group uses various processes in its production, especially in the automotive glass and building glass segments. The glass products made there have to offer special functions, such as guaranteeing heat protection and high light transmission at the same time (Fig. 1). Some of the layers applied also have different tasks. If they are electrical
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