Patent ID: 8037716

Claim:
A method for fabricating sheets of glass comprising: (A) producing a glass ribbon using a drawing process, the ribbon having: (i) a center line, (ii) a first edge, (iii) a second edge, (iv) a first bead portion which begins at the first edge and extends inward towards the center line, and (v) a second bead portion which begins at the second edge and extends inward towards the center line, and (B) cutting sheets from the glass ribbon; wherein at a first down-the-draw location, step (A) includes cooling at least one of the bead portions at a rate such that the beat flux Q″ b in kilowatts/meter 2 from the thickest part of the bead portion satisfies the relationship: Q″ b =Q″ q +ΔQ; where: (a) each of Q″ b , Q″ q , and ΔQ″ are heat fluxes from one side of the ribbon; (b) the first down-the-draw location is below the point where the center line and bead portions of the ribbon have reached their final thicknesses; (c) Q″t q is the heat flux in kilowatts/meter 2 at the first down-the-draw location at a transverse position adjacent to the bead portion at which the ribbon's thickness t q equals 1.05*t center , where t center is the final thickness of the ribbon at the center line; and (d) ΔQ″≧(t b /t q −1)Q″ q +10 kilowatts/meter 2 , where t b is the thickness of the thickest part of the bead portion.