Glass cutting method which does not involve breaking

• Main Author: GAUME OLIVIER,VALLADEAU SERGE
• Format: Patent
• Language: English
• Published: 14.03.2007
• Subjects: CHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUSENAMELS; CHEMISTRY; GLASS; JOINING GLASS TO GLASS OR OTHER MATERIALS; MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES; METALLURGY; MINERAL OR SLAG WOOL; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS,MINERALS OR SLAGS; SURFACE TREATMENT OF GLASS

A method for cutting a glazing unit without applying a breaking force. The method applies a treatment to the glass sheet that generates stresses with a biaxial distribution, the stresses being such that the K factor is between 0.05 and 0.4 MPa.m1/2; the K factor being defined by K=[∫sigmaz2.H(sigmaz).dz]1/2 in which z is a position in the thickness, sigmaz is intensity of the approximately isotropic biaxial stress at the position z, H(sigmaz) is equal to 1 if sigmaz is greater than 0 and is equal to 0 if sigmaz is less than or equal to 0, with the convention that extension is denoted by positive values and compression by negative values. A subcrack deeper than 10 mum is scored along the desired line of cutting, the subcrack reaching that region of the glazing in extension. The method allows cutting of glass, without breaking it, along curves with a small radius of curvature, or of glass strips of width similar to the thickness, or of frame shapes used as inserts in a flat field emission display.