US 2026/0092002 A1Published application

Process and apparatus for producing flat glass

AssigneesSchott AG, SCHOTT Technical Glass Solutions GmbH

InventorsVolker Plapper, Georg Haselhorst, Jochen Alkemper, Tommy Schröder, Michael Meister

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Abstract

A process includes directing a laser beam at a glass strip so it traverses a line in a drawing direction of the horizontally moving glass strip. A point of incidence of the laser beam is chosen so the line forms an envisaged dividing line between a useful region and a thickened edge region and the point of incidence on the glass is at a position where a temperature of the glass is within a range between an upper viscosity of 1010 dPas and a lower viscosity of 1015 dPas. The laser beam photothermally processes the glass strip so a gap is formed along the line between the useful region and the thickened edge region to obtain a glass strip with a homogeneous glass thickness and a new edge parallel to the drawing direction and a separated thickened edge region. The glass strip with homogeneous thickness is cooled after separation.

A process for producing a glass strip with homogeneous glass thickness, the process comprising:

obtaining a glass strip from a melt by a drawing process, wherein the glass strip has a useful region and thickened edge regions with respect to the useful region which extend along edges of the glass strip in a drawing direction;
cooling the glass strip, wherein during the cooling, a laser beam is directed at the glass strip by at least one laser such that it traverses a line in the drawing direction of the horizontally moving glass strip owing to a movement of the glass strip, wherein a point of incidence of the laser beam is chosen such that the line forms an envisaged dividing line between the useful region and the thickened edge region and the point of incidence on the glass is at a position where a temperature of the glass is within a range between an upper viscosity of 1010 dPas and a lower viscosity of 1015 dPas, wherein the laser beam photothermally processes the glass strip in an irradiated region such that a gap is formed along the line between the useful region and the thickened edge region and a glass strip with a homogeneous glass thickness and a new edge parallel to the drawing direction and a separated thickened edge region is obtained, and wherein the cooling of the glass strip with homogeneous thickness is continued after separation;
wherein the useful region of the glass strip has a thickness of more than 0.3 mm, or
wherein the useful region of the glass strip has a thickness of more than 0.1 mm and the drawing process comprises a float process and the glass strip is lifted from a float bath, or
wherein the glass strip is subject to the following condition:
F
⁢
B
=
α
l
⁢
i
⁢
q
+
α
2
⁢
0
-
3
⁢
0
⁢
0
30
·
10
-
6
/
K
·
(
4
.
6
log
⁡
(
η
l
⁢
i
⁢
q
/
dPas
)
)
2
·
d
⁢
T
d
⁢
log
⁢
(
η
)
⁢
(
log
⁡
(
η
/
dPas
)
=
1
⁢
3
)
-
28
⁢
°
⁢
C
.
·
T
1
⁢
3
650
⁢
°
⁢
C
.
>
1
where αliq=a linear coefficient of thermal expansion above a glass transformation temperature of the glass, α20-300=a linear coefficient of thermal expansion of the glass at temperatures between 20° C. and 300° C., ηliq=a liquidus viscosity of the glass,
d
⁢
T
d
⁢
log
⁢
(
η
)
⁢
(
log
⁢
(
η
)
=
13
)
=
a
slope of a viscosity curve at an upper cooling point or at a temperature at which the glass has a viscosity η of 1013 dPas, and T13=a temperature at which the glass has a viscosity η of 1013 dPas.

118 more elements

Abstract

Claims23