Method for decoating a glass panel

Abstract

When decoating a glass panel (3), a decoating tool (6) with a circular-cylindrical grinding element (8) is used, which element is set to rotate around its axis. In the end face of the grinding element (8) that is used when the active face (9) is decoated, a hole (10) and at least one radial groove (11) are provided. The decoating tool (6) is placed at a spot (A) on the glass panel (3) in a movement (arrow 13) that is oriented at an acute angle to the plane of the glass panel (3), which lies between the ends (B) and (C) of the strip-shaped decoating area (14) and moves first to the one end (B) (arrow 15) and then to the other end (C) (arrow 16) in order to strip coating from the glass panel (3) in the decoating area (14).

Claims

1. A method for decoating a glass panel, comprising: placing a decoating tool on a surface of the glass panel at a spot that is offset from ends of the glass panel inside an area of the glass panel that is to be decoated, so that the decorating tool does not lie at an end of the area of the glass panel that is to be decorated; moving the decoating tool up to a first end of the ends of the glass panel; and then moving the decoating tool in an opposite movement relative to the glass panel up to a second end of the ends of the glass panel, so that an initial area of the glass panel that is to be decoated is covered twice, wherein the decoating tool comprises a grinding element with a generally round active face that is concentric to an axis of rotation that passes through a center hole in the active face.

2. The method according to claim 1, wherein the decoating tool is moved during placement on the surface of the glass panel in a direction that encompasses an acute angle with the surface of the glass panel, whereby paths of movement of the decoating tool are straight or curved.

3. The method according to claim 2, wherein the active face has at least one groove.

4. The method according to claim 2, further comprising directing a gas stream toward the active face of the decoating tool, in order to blow away coating material that accumulates during decoating.

5. The method according to claim 2, wherein the glass panel is scored in at least one decoated area in order to prepare for division of the glass panel.

6. The method according to claim 2, wherein the glass panel is scored in a center of the at least one decoated area.

7. The method according to claim 1, wherein the active face has at least one groove.

8. The method according to claim 1, further comprising directing a gas stream toward the active face of the decoating tool, in order to blow away coating material that accumulates during decoating.

9. The method according to claim 1, wherein the glass panel is scored in at least one decoated area in order to prepare for a division of the glass panel.

10. The method according to claim 9, wherein the glass panel is scored in a center of the at least one decoated area.

11. The method according to claim 1, wherein the center hole is a blind hole.

12. The method according to claim 1, wherein the center hole prevents a convex area being formed in the active face.

13. The method according to claim 1, wherein there are four grooves in the active face, each groove extending from the center hole to a periphery of the active face.

14. The method according to claim 1, wherein the grinding element is formed from polymer in which abrasive material is embedded.

15. The method according to claim 14, wherein the abrasive material is SiC or Al.sub.2O.sub.3.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) Further details and features as well as advantages of the method according to the invention follow from the description below of a decoating as a preferred embodiment based on the drawings. Here:

(2) FIG. 1 shows a device for decoating and scoring a glass panel in oblique view,

(3) FIG. 2 shows a decoating tool in oblique view,

(4) FIG. 3 shows diagrammatically the mounting of the decoating tool, and

(5) FIG. 4 shows diagrammatically the course of a decoating process.

DETAILED DESCRIPTION OF THE INVENTION

(6) A device 1 that is shown in FIG. 1 is designed like a glass-cutting table and has a support surface 2 (table) that is designed as an air-cushion bed for a glass panel 3 that is to be treated. A bridge 4 that can be guided to move on the side edges of the support surface 2 is assigned to the support surface 2. On the bridge 4, a sled 5 that can be moved along the bridge 4 is provided.

(7) Drives are provided both for moving the bridge 4 along the support surface 2 and for moving the sled 5 along the bridge 4.

(8) By moving the bridge 4, on the one hand, and/or the sled 5 with a processing head comprising a decoating tool 6, on the other hand, any (straight/curved) paths, for example corresponding to the provided division pattern of the glass panel 3, can be pulled away.

(9) For operating and controlling the device 1, a control and operating console 7 is provided.

(10) The processing head that is provided on the sled 5 has the decoating tool 6 as an essential component, which tool can be raised and lowered by a drive crosswise to the plane of the support surface 2. A rotary drive is assigned to the decoating tool 6, which is designed in the example as a grinding tool with a grinding element 8 (FIG. 2) in order to put the grinding element 8 in rotation around its axis when the grinding tool is used to strip a coating from a glass panel 3.

(11) In a preferred embodiment, the processing head also has a tool for scoring the glass panel 3, so that after the decoating corresponding to the desired division pattern of the glass panel 3, the glass panel 3 in the area of the strips in which the coating has been stripped (“decoating areas”) is scored so that the glass panel 3 can then be divided (broken) into blanks.

(12) The tool for scoring the glass panel 3 can also be provided on a processing head, which is arranged on a sled that is separate from the sled 5.

(13) The grinding tool that can preferably be used within the framework of the invention is diagrammatically depicted in an embodiment in FIG. 2. It has a (circular-)cylindrical grinding element 8 with an active face 9, which is placed on the glass panel 3 for decoating.

(14) A hole 10 (blind hole) empties into the center of the active face 9 of the grinding element 8, i.e., concentric to its axis of rotation. The hole 10 prevents a convex (cone-shaped) area from being formed in the area around the axis of rotation during the wear and tear of the grinding element 8 (the wear and tear of its end face that serves as an active face 9).

(15) In addition, four grooves 11 are provided in the active face 9 of the grinding element 8 in the embodiment that is shown, which grooves extend from the center hole 10 to the peripheral face of the grinding element 8. The number of grooves 11 is insignificant; one, two, three, four as shown, or even more grooves 11 can be provided. The grooves 11 can also be of different depths.

(16) The center planes of the grooves 11 preferably, but not necessarily, go through the axis of the grinding element 8.

(17) The grooves 11 can also be formed by axis-parallel grooves, which are open toward the side face of the grinding element 8 and end in its active face.

(18) The grinding element 8 can consist of an elastic material (polymer), in which abrasive material (SiC, Al.sub.2O.sub.3) is embedded.

(19) In FIG. 2, it is shown that a nozzle 12 is assigned to the grinding element 8 of the grinding tool, which nozzle is loaded with compressed gas (compressed air) in order to blow away stripped coating material.

(20) The air stream has the additional advantage that the separating agent powder that is usually provided between glass panels and that can be still be found on the surface of the disk after support on the cutting table is blown away from the operating area of the grinding element 8. The separating agent powder could have been cooled by grinding heat and thus could form undesirable residue. Also, other dirt particles are removed. Another effect of the air stream: it cools during decoating.

(21) When implementing the method according to the invention with use of the described device, the procedure is as follows, for example:

(22) After a glass panel 3 has been placed on the support surface 2 of the device 1 and has been oriented—using activatable contacts—the grinding tool of the decoating tool 6 is mounted in a “flying” manner with its grinding element 8 in a straight or curved movement that is oriented at an acute angle to the plane of the glass panel (arrow 13 in FIG. 3) and thus lands in a grinding-in manner snugly against the coating of the glass panel 3.

(23) In this case, the grinding element 8 is applied to the item “on contact,” so that it is not necessary to determine the thickness of the glass panel 3 and/or the wear and tear of the grinding element 8 or to control the application of the grinding element 8 corresponding to the determined glass thickness and/or the wear and tear of the grinding element 8. “On contact” means: moving the end face of the grinding element 8 up to the surface that is to be treated (ground) and stressing the grinding element 8 against the surface with a predetermined force.

(24) It is further provided (cf. FIG. 4) that Item A, in which the grinding element 8 strikes the glass panel 3 or its coating, does not lie on the end of an area 14 (indicated in broken lines in FIG. 4), which is to be decoated, but rather at some distance from the ends B and C of the area 14. Then, the grinding tool is moved with its grinding element 8 by moving the bridge 4 and/or the sled 5, which holds the processing head with the decoating tool 6, in the one end B of the area 14 in which it is to be decoated (arrow 15), and then after reversal of the direction of movement (arrows 16) is moved from the end B to the other end C of the strip-shaped area 14 while coating is stripped. Stripped coating material is blown away by the air stream that exits from the nozzle 12. As soon as the end C of the area 14 is reached, the grinding tool is lifted from the glass disk 3 (arrow 17). Then, additional areas 14, as described above, can be decoated. The movements of the processing head with the decoating tool 6 correspond to the desired division pattern (the latter is indicated in broken lines in FIG. 4 by way of example), after which the glass panel 3 is to be scored and is to be divided into blanks after the areas 14 have been decoated corresponding to the division pattern. The score lines can lie in the center of decoated areas or eccentrically to the latter.

(25) When the grooves 11 in the active face 9 of the grinding element 8 have become too flat because of the wear and tear of the grinding element 8, the grooves can be reworked (expanded in depth). To this end, for example, in an area of the support surface 2 of the device 1, a system for reworking can be provided, which is equipped, for example, with a tool like a circular saw blade. Instead of reworking a groove 11, there is the option of cutting a new groove 11 in the active face 9 of the grinding element 8.

(26) In summary, an embodiment of the invention can be described as follows:

(27) When decoating a glass panel 3, a decoating tool 6 with a circular-cylindrical grinding element 8 is used, which element is set to rotate around its axis. In the end face of the grinding element 8 that is used when the active face 9 is decoated, a hole 10 and at least one radial groove 11 are provided. The decoating tool 6 is placed at a spot A on the glass panel 3 in a movement (arrow 13) that is oriented at an acute angle to the plane of the glass panel 3, which lies between the ends B and C of the strip-shaped decoating area 14 and moves first to the one end B (arrow 15) and then to the other end C (arrow 16) in order to strip coating from the glass panel 3 in the decoating area 14.