METHODS OF FABRICATING FLAT GLASS WITH LOW LEVELS OF WARP

摘要

A method of fabricating glass sheets ( 13 ) is provided in which the sheets are cut from a glass ribbon ( 15 ) composed of a glass having a glass transition temperature range (GTTR). The ribbon ( 15 ) is formed by a drawing process in which edge rollers ( 27 a ,27 b) contact the glass ribbon ( 15 ) at a location along the length of the ribbon where the temperature along the center line ( 17 ) of the ribbon ( 15 ) is above the GTTR. The edge rollers ( 27 a ,27 b) locally cool the ribbon ( 15 ), and the cooling produces a sine wave type buckling (S-warp) along the edges of the glass sheets ( 13 ). The S-warp is reduced or eliminated by heating the bead portions ( 21 a , 21 b) of the ribbon ( 15 ) and/or portions of the ribbon (the S-warp portions 25 a and 25 b) which are located next to the bead portions ( 21 a , 21 b) and/or by cooling the center portion of the ribbon ( 15 ) at least one location along the length of the ribbon ( 15 ) where the temperature at the ribbon's center line ( 17 ) is within the GTTR.