Patent Grant
9630290
The present disclosure relates generally to glass sheets and methods of shaping glass sheets and, more particularly, to glass sheets with an edge portion including first and second bevel surfaces and methods of shaping glass sheets by removing first and second portions to form respective first and second bevel surfaces.
The process of manufacturing glass sheets, including glass sheets for use in liquid crystal displays, typically involves melting of raw material, forming a glass sheet therefrom, and then finishing the glass sheet. The finishing operation, in turn, frequently involves cutting the glass sheet to size, edge finishing, cleaning and packaging.
The following presents a simplified summary of the disclosure in order to provide a basic understanding of some example aspects described in the detailed description.
In one aspect, a method of shaping a glass sheet is disclosed herein. The glass sheet includes a first glass-sheet surface, a second glass-sheet surface opposing the first glass-sheet surface, a thickness defined between the first glass-sheet surface and the second glass-sheet surface, and an edge portion including an end surface including a median crack surface. The first glass-sheet surface and the end surface intersect along a first edge of the edge portion. The second glass-sheet surface and the end surface intersect along a second edge of the edge portion. The median crack surface extends from either the first or second edge of the edge portion along the end surface. The method includes a step (I) of removing a first portion of the glass sheet including the first edge with at least one rotating cup wheel, thereby forming a first bevel surface between the first glass-sheet surface and the end surface. The method also includes a step (II) of removing a second portion of the glass sheet including the second edge with the at least one rotating cup wheel, thereby forming a second bevel surface between the second glass-sheet surface and the end surface. The method then includes a step (III) of removing a third portion of the glass sheet including the remainder of the end surface with a rotating grooved wheel to form an apex surface between the first and second bevel surfaces. In accordance with the method, step (I) and/or step (II) removes the median crack surface.
In one example of the aspect, steps (I), (II) and (III) provide the glass sheet with a shaped edge that exhibits a probability of failure of less than 5% at an edge stress of 135 MPa.
In another example of the aspect, steps (I) and (II) are conducted simultaneously.
In still another example of the aspect, the at least one rotating cup wheel of step (I) comprises a first rotating cup wheel and the at least one rotating cup wheel of step (II) comprises a second rotating cup wheel.
In another example aspect, the at least one rotating cup wheel is selected from the group consisting of a metal bond diamond wheel and a resin bond diamond wheel.
In a further example aspect, the bonded diamond wheel includes a mesh size ranging from 400 to 1000.
In still another example aspect, the grooved wheel is a metal bond wheel with a diamond mesh size ranging from 600 to 1000.
In yet another example aspect, the grooved wheel comprises a groove configured to accommodate a profile of the glass sheet defined by the first bevel surface, the apex surface, and the second bevel surface.
In a further example of the aspect, after step (III), further comprising the step (IV) of contacting the glass sheet with a rotating polish wheel to polish at least one of the first bevel surface, the apex surface, and the second bevel surface.
In yet a further example of the aspect, after step (III), further comprising the step (IV) of providing a rounded intersection between at least one of the first glass-sheet surface and the first bevel surface, the first bevel surface and the apex surface, the apex surface and the second bevel surface, and the second bevel surface and the second glass-sheet surface.
In another example of the aspect, after step (III), further comprising the step (IV) of contacting the glass sheet with a rotating polish wheel including a wheel body selected from the group consisting of a rubber bond wheel, a resin bond wheel, and a polymer bond wheel and a cutting material selected from the group consisting of one or more of a diamond grit, a silicon carbide grit, an alumina grit and a ceria grit.
In yet another example of the aspect, the median crack surface extends less than or equal to 15% of the thickness of the glass sheet.
In another example of the aspect, a shaped edge is made in accordance with the aspect, wherein the glass sheet comprising the shaped edge exhibits a probability of failure of less than 5% at an edge stress of 135 MPa.
In another aspect, a method of shaping a glass sheet is disclosed herein. The glass sheet includes a first glass-sheet surface, a second glass-sheet surface opposing the first glass-sheet surface, a thickness defined between the first glass-sheet surface and the second glass-sheet surface, and an edge portion including an end surface including a median crack surface. The first glass-sheet surface and the end surface intersect along a first edge of the edge portion. The second glass-sheet surface and the end surface intersect along a second edge of the edge portion. The median crack surface extends from either the first or second edge of the edge portion along the end surface. The method includes a step (I) of removing a first portion of the glass sheet including the first edge, thereby forming a first bevel surface between the first glass-sheet surface and the end surface. The method also includes a step (II) of removing a second portion of the glass sheet including the second edge, thereby forming a second bevel surface between the second glass-sheet surface and the end surface. The method then includes a step (III) of removing a third portion of the glass sheet including the remainder of the end surface, thereby forming an apex surface between the first and second bevel surfaces. In accordance with the method, step (I) and/or step (II) removes the median crack surface.
In one example of the aspect, steps (I), (II) and (III) provide the glass sheet with a shaped edge that exhibits a probability of failure of less than 5% at an edge stress of 135 MPa.
In another example of the aspect, steps (I) and (II) are conducted simultaneously.
In yet a further example of the aspect, step (I) and/or step (II) includes chamfering with at least one rotating cup wheel.
In still a further example of the aspect, step (III) includes removing the third portion with a rotating grooved wheel.
In another example of the aspect, a shaped edge is made in accordance with the aspect, wherein the glass sheet comprising the shaped edge exhibits a probability of failure of less than 5% at an edge stress of 135 MPa.
In a further aspect, a glass sheet comprises a first glass-sheet surface and a second glass-sheet surface opposing the first glass-sheet surface with a thickness defined between the first glass-sheet surface and the second glass-sheet surface. The glass sheet further includes an edge portion including a first bevel surface intersecting the first glass-sheet surface and an apex surface, and a second bevel surface intersecting the second glass-sheet surface and the apex surface. The glass sheet exhibits a probability of failure of less than 5% at an edge stress of 135 MPa.
These and other aspects are better understood when the following detailed description is read with reference to the accompanying drawings, in which:
Examples will now be described more fully hereinafter with reference to the accompanying drawings in which example embodiments are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, aspects may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
Example methods of the disclosure will be described with initial reference to the glass sheet 10 illustrated in
Considering the glass sheet 10 in more detail, as shown in
The median crack surface 22 can be formed during the scoring and separation of a glass sheet 10, with the depth 28, and thus extent, of the median crack surface 22 being determined at least in part based on how these processes are carried out. Typically, the depth 28 of the median crack surface 22 depends on the thickness 16 of the glass sheet 10 being scored and is about 10% to 15% of the thickness 16. Glass sheets for incorporation in a liquid crystal display typically have a thickness of 2 mm or less, e.g. 0.7 mm or less, 0.5 mm or less, or 0.3 mm or less. Thus, for example, the median crack surface 22 can extend from either the first or second edge 24 or 26 of the edge portion 18, along the end surface 20, less than or equal to 15% of the thickness 16 of the glass sheet 10, e.g. extending less than or equal to 0.3 mm for a glass sheet 10 with a thickness 16 of 2 mm.
The median crack surface 22 that may be generated by way of mechanical scoring or other process can decrease the edge quality of the glass sheet 10, provide initial crack locations that may undesirably propagate to cause crack failure or other undesirable characteristics. Thus, removal of the median crack surface 22 from the glass sheet 10 may be desired. As discussed below, the median crack surface 22 can be removed by subsequent shaping steps, with the depth 28 of the median crack surface 22 determining the amount of glass material that can be removed in order to accomplish removal of the median crack surface 22.
The glass sheet 10 can also be free of lateral cracks along the edge portion 18. Like the median crack surface 22, lateral cracks can be formed during the scoring and separation of a glass sheet 10 and can decrease the edge quality of the glass sheet 10 and likewise increase the probability of crack failure under edge stress conditions. Accordingly, an absence of lateral cracks may also be desired.
Considering now the method of shaping the glass sheet 10, the method can include a step (I) of removing a first portion 40 of the glass sheet 10 including the first edge 24 with at least one rotating cup wheel 42. As shown in
As shown in
Considering steps (I) and (II) in more detail, the steps can be carried out to remove flaws and/or defects caused by scoring. The steps can also be carried out to provide the first and second bevel surfaces 44 and 72 in smooth forms and/or free of particles, such as glass chips. Various factors, such as the length of the glass sheet 10 that is available for contact by the at least one rotating cup wheel 42, the force applied thereby, the thickness 16 of the glass sheet 10, and the material properties of the glass sheet 10, can be varied or optimized toward these ends.
Steps (I) and (II) can be carried out, for example, wherein the at least one rotating cup 42 of step (I) and the at least one rotating cup 42 of step (II) are angled with respect to the glass sheet 10 so as to form the first and second bevel surfaces 44 and 72 with a chamfer angle φ of, e.g. to 40° to 140°, e.g. 50° to 70°, or about 60° therebetween, as shown in
Steps (I) and (II) can be carried out in various orders, e.g. simultaneously, sequentially, or in reverse order, as desired, and with one or more rotating cup wheels 42, also as desired. Thus, as shown in
Following steps (I) and (II), the method also includes then a step of (III) removing a third portion 90 of the glass sheet 10 including the remainder of the end surface 20 with a rotating grooved wheel 92 to form an apex surface 94 between the first and second bevel surfaces 44 and 72, as shown in
Considering step (III) in more detail, the step can be carried out to remove a minimal amount of the glass sheet 10 necessary to form the apex surface 94. This step can also be carried out to provide the glass sheet 10 with a desired profile for the glass sheet 10 defined by the first bevel surface 44, the apex surface 94, and the second bevel surface 72, e.g. to provide a desired shape and/or ensure optimal quality for the glass sheet 10 with respect to a variety of applications. Various factors, such as the chamfer angle φ of the glass sheet 10 following steps (I) and (II), the final shape that is desired for the edge 100 of the glass sheet 10, and the amount of material to be removed from the glass sheet 10, can be varied or optimized toward these ends.
Step (III) can be carried out, for example, without removing material from the first or second bevel surface 44 or 72, e.g. without removing material other than the third portion 90 of the glass sheet 10 including the remainder of the end surface 20. Thus, for example, the grooved wheel 92 can include a groove that is sufficiently wide to accommodate a profile of the glass sheet 10 defined by the first bevel surface 44, the apex surface 94, and the second bevel surface 72. Suitable exemplary groove shapes include (i) groove height=0.762 mm, groove base width=0.3048 mm±0.0254 mm, R=0.127 mm±0.0254 mm, and groove angle of 80°; (ii) groove height=0.762 mm, groove base width=0.3556 mm±0.0254 mm, R=0.127 mm±0.0254 mm, and groove angle of 60°; and (iii) groove height=0.254 mm and R=0.508 mm±0.0254 mm. As will be appreciated, a grooved wheel 92 with a groove dimensioned to accommodate the profile of the glass sheet 10 can be used to remove the third portion 90 of the glass sheet 10 with precision, by contacting the grooved wheel 92 to the third portion 90 of the glass sheet 10 and advancing the wheel 92 toward the glass sheet 10, without any surface of the grooved wheel 92 contacting the first or second bevel surface 44 or 72 and thus without removing material from either.
In accordance with the method, step (I) and/or step (II) can remove the median crack surface 22, as shown in
The combination of steps (I), (II), and (III) allows a reduction in the amount of material to be removed from glass sheets, relative to other edge finishing processes, based on reduced depths of cutting. This in turn allows the use of cup wheels and grooved wheels with relatively finer grit, at potentially higher glass traverse speeds, providing better edge strength and quality. The reduction in the amount of material removed is calculated to be about 1:1.8-2.4, or in other words an approximately 2 fold reduction. This eliminates about half of the volume of ground glass and other debris.
Following step (III), the method can also include then a step of (IV) contacting the glass sheet 10 with a rotating polish wheel 110 at one or more surfaces of the edge 100 of the glass sheet 10 and/or between one or more of the surfaces, as shown in
The method can be performed in various configurations, such as an assembly-line style set-up, a modular type set-up, or other similar set-ups. For example, for an assembly-line style set-up, the glass sheet 10 can be fixed in a support device 48 and moved along the assembly line, e.g. at a constant rate. A first rotating cup wheel 80 can be inclined at a desired angle with respect to the glass sheet 10 and used to grind the glass sheet 10 to remove the first portion 40 thereof, including the first edge 24, as the glass sheet 10 passes, to form the first bevel surface 44. A second rotating cup wheel 82 can be similarly inclined at a desired angle and used to grind the glass sheet 10 to remove the second portion 70 thereof, including the second edge 26, as the glass sheet 10 passes, to form the second bevel surface 72. The order of formation of the first and second bevel surfaces 44 and 72 can also be interchanged. The rotating grooved wheel 92 can be oriented such that the profile thereof is centered with respect to the profile of the first and second bevel surfaces 44 and 72 of the glass sheet 10, and used to grind the glass sheet 10 to remove the third portion 90 of the glass sheet 10, including the remainder of the end surface 20, as the glass sheet 10 passes, to form the apex surface 94. The rotating polish wheel 110 can be oriented similarly to the rotating grooved wheel 92, e.g. centered, and used to impart a desired finish quality to the edge of the glass sheet 10 and/or to round any sharp corners.
In another aspect, a glass sheet 10 is provided, as shown in
The glass sheet 10 including the shaped edge can exhibit a probability of failure of less than 5% at an edge stress of 135 MPa. The glass sheet 10 can be, for example, one that would be suitable for use in a liquid crystal display. The glass sheet 10 can have a thickness 16, for example, of 2 mm or less, e.g. 0.7 mm or less, 0.5 mm or less, or 0.3 mm or less. The glass sheet 10 can be free of coatings that might otherwise be used to strengthen the glass sheet 10, e.g. by increasing edge strength.
In another aspect, a method of shaping a glass sheet 10 is provided. The glass sheet 10 can be as described above, including and an edge portion 18 including an end surface 20 including a median crack surface 22, again as shown in
The method can include a step (I) of removing a first portion 40 of the glass sheet 10 including a first edge 24 thereof, thereby forming a first bevel surface 44 between a first glass-sheet surface 12 and an end surface 20 of the glass sheet 10, again as shown in
The method can also include a step (II) of removing a second portion 70 of the glass sheet 10 including a second edge 26 thereof, thereby forming a second bevel surface 72 between a second glass-sheet surface 14 and the end surface 20, again as shown in
Steps (I) and (II) can be conducted simultaneously, sequentially, or in reverse order, also as described above.
The method can also include then a step (III) of removing a third portion 90 of the glass sheet 10 including the remainder of the end surface 20, thereby forming an apex surface 94 between the first and second bevel surfaces 44 and 72, again as shown in
In accordance with this method, step (I) and/or step (II) can remove the median crack surface 22, also as described above.
In another aspect, a glass sheet 10 is provided, again as shown in
Methods of the present invention can avoid excessive amounts of material being removed in a single step, thereby allowing a finger grit wheel to be used that can enhance edge quality. Moreover, removing the material in multiple steps can avoid grooved grinding wheels that may otherwise change in shape over time, thereby affecting the overall shape of the edge portion. In addition, use of the rotating cup wheel 42 to address the first and second portion to achieve the bevel surfaces helps manage glass particle generation and reduce the chances of machined glass particles from landing on the first or second glass-sheet surface that may otherwise negatively affect glass surface quality. Further still, the removal of material with the rotating cup wheel can provide sufficient clearance to allow machined glass particles to be freely removed from the vicinity of the glass sheet.
Glass sheets were prepared in accordance with the methods disclosed herein. The dimensions of the glass sheets, as cut to size before shaping, were 400 mm×125 mm×0.5 mm. First and second bevel surfaces were formed at angles α and β, both of 70°, with respect to the corresponding edge portion of the glass sheet. The apex was formed to have an apex width of 0.3 mm. The first bevel surface, apex surface, and second bevel surface were then polished, and the intersections therebetween were rounded. The result was a glass sheet lacking a median crack surface and including a shaped edge.
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the claimed invention.
The present application is a divisional application and claims the priority benefit of U.S. application Ser. No. 13/599,090, filed on Aug. 30, 2012, which has since issued as U.S. Pat. No. 9,028,296, the content of which is relied upon and incorporated herein by reference in its entirety.
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| Parent | 13599090 | Aug 2012 | US |
| Child | 14699020 | US |
