CN113165936B

CN113165936B - Method for manufacturing glass plate

Info

Publication number: CN113165936B
Application number: CN201980078134.6A
Authority: CN
Inventors: 奥隼人; 冈田贞治
Original assignee: Nippon Electric Glass Co Ltd
Current assignee: Nippon Electric Glass Co Ltd
Priority date: 2018-12-18
Filing date: 2019-11-26
Publication date: 2022-12-02
Anticipated expiration: 2039-11-26
Also published as: WO2020129544A1; KR20210100596A; CN113165936A; JP2020097503A; JP7092018B2

Abstract

A method for manufacturing a Glass Plate (GP) comprises a cooling roll (3) for cooling the end part of a glass ribbon (G) in the width direction right below a forming body (2), and a conveying roll (4) which is arranged at a position lower than the cooling roll (3) and conveys the glass ribbon (G) downwards, wherein a scribing line (S) is engraved on the glass ribbon (G) at the position lower than the conveying roll (4), the glass ribbon (G) is broken along the scribing line (S), a contact part (G1) of the glass ribbon (G) and the conveying roll (4) is positioned at a position closer to the center side in the width direction than a contact part (G2) of the glass ribbon (G) and the cooling roll (3), and a starting point (S1) and an end point (S2) of the scribing line (S) are positioned between the contact part (G1) of the glass ribbon (G) and the conveying roll (4) and the contact part (G2) of the glass ribbon (G) and the cooling roll (3).

Description

Method for manufacturing glass plate

Technical Field

The present invention relates to a method for producing a glass sheet, and more particularly, to a method for producing a glass sheet cut out from a glass ribbon formed by a down-draw method.

Background

As is known, a method for producing a glass sheet using a down-draw method (e.g., an overflow down-draw method) includes a forming step of forming a glass ribbon and a cutting step of cutting a glass sheet from the formed glass ribbon.

As a specific example, patent document 1 discloses a technique of performing a forming process using a cooling roll (pulling roll) that cools an end portion of a glass ribbon in a width direction directly below a forming body, and a plurality of conveying rolls (annealing roll and backup roll) that are disposed below the cooling roll and convey the glass ribbon downward. Patent document 1 also discloses a cutting step of cutting a glass sheet into short pieces by forming a score line in a glass ribbon at a position below a plurality of conveyance rollers and breaking the glass ribbon along the score line.

On the other hand, patent document 1 (fig. 4 and the like of the document) discloses that a scribing blade is used to scribe a scribing line at a widthwise end portion (an ear portion having a wall thickness larger than a widthwise central portion) of a glass ribbon at the time of performing a cutting process. In detail, this document discloses that the end point of the scribing line is located at one widthwise end of the glass ribbon. The widthwise end of the glass ribbon corresponds to a contact portion where the glass ribbon contacts the cooling roll (see fig. 1 of the document).

Patent document 1 (fig. 1 of the document) discloses a state in which a contact portion where the glass ribbon contacts the cooling roll and a contact portion where the glass ribbon contacts the conveying roll overlap in the width direction when the forming process is performed.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-90448

Disclosure of Invention

Problems to be solved by the invention

Generally, the contact portion of the glass ribbon formed by the down-draw method and the cooling roll is insufficient in strength. Therefore, if the start point and the end point of the score line are located at the contact portion, a longitudinal crack (a crack along the longitudinal direction of the glass ribbon) may occur in the glass ribbon from the contact portion as the start point. The scribing position of the scribing line disclosed in patent document 1 is not preferable from the viewpoint of preventing the occurrence of the longitudinal crack.

In order to prevent the occurrence of longitudinal cracks, if the start point and the end point of the score line are located on the center side in the width direction of both the contact portion with the cooling roll and the contact portion with the conveyance roll of the glass ribbon, the width direction dimension of the portion where the score line is not formed is increased. Therefore, when the glass ribbon is broken along the scribe line, a large amount of glass frit scatters.

Further, the contact portion of the glass ribbon formed by the down-draw method with the cooling roll has a surface that is not smooth compared with the portion on the widthwise center side of the glass ribbon. Therefore, as disclosed in patent document 1, when the contact portion of the glass ribbon with the cooling roller and the contact portion of the glass ribbon with the conveying roller overlap in the width direction of the glass ribbon, the surface of the conveying roller and the uneven surface in the contact portion of the glass ribbon with the cooling roller contact. In this state, there is a possibility that irregularities due to abrasion may be formed on the surface of the conveying roller with use over time. When the glass frit enters the concave portion on the surface of the conveying roller, the strength of the contact portion where the glass ribbon contacts the conveying roller may be reduced due to damage or the like. Therefore, while the glass ribbon is conveyed downward, a longitudinal crack is likely to occur in the glass ribbon from the contact portion.

From the above-described viewpoint, an object of the present invention is to suppress the occurrence of longitudinal cracks in a glass ribbon until the glass ribbon is formed and a glass plate is cut, and to reduce the amount of scattering of glass powder when the glass ribbon is broken along a scribe line.

Means for solving the problems

The present invention has been made to solve the above problems, and provides a method for manufacturing a glass sheet, including a forming step of forming a glass ribbon by a down-draw method and a cutting step of cutting a glass sheet from the formed glass ribbon, wherein in the forming step, a process of cooling a widthwise end portion of the glass ribbon by a cooling roll and a process of conveying the glass ribbon downward by a conveying roll disposed below the cooling roll are performed, and in the cutting step, a process of scribing a glass ribbon at a position below the conveying roll and a process of breaking the glass ribbon along the scribing line are performed with respect to the glass ribbon being conveyed downward, wherein a contact portion where the glass ribbon contacts the conveying roll is located on a widthwise central side of a contact portion where the glass ribbon contacts the cooling roll, and a start point and an end point of the scribing line are located between the contact portion where the glass ribbon contacts the conveying roll and the contact portion where the glass ribbon contacts the cooling roll. Here, the "contact portion" is not limited to a portion where the cooling roller and the conveying roller are in contact with the glass ribbon, and includes a portion that is a locus after contact (hereinafter, the same applies).

According to this configuration, the contact portion of the glass ribbon with the conveyance roller and the contact portion of the glass ribbon with the cooling roller do not overlap in the width direction. Therefore, even if the surface of the contact portion of the glass ribbon with the cooling roll is not smooth, the surface of the conveyance roll does not contact the uneven surface. This prevents the surface of the conveyance roller from being uneven due to wear, and suppresses a decrease in the strength of the contact portion where the glass ribbon contacts the conveyance roller. As a result, when the conveying roller conveys the glass ribbon in the forming step, the occurrence of vertical cracks in the glass ribbon is suppressed starting from the contact portion where the glass ribbon contacts the conveying roller. The score line does not reach the contact portion where the glass ribbon contacts the cooling roll. Therefore, the contact portion of the glass ribbon with the cooling roll is less susceptible to the influence of the scribing line. As a result, it is possible to suppress the occurrence of a longitudinal crack in the glass ribbon starting from the contact portion where the glass ribbon contacts the cooling roll when the score line is scribed in the cutting step. Further, the score line passes through (crosses over) the contact portion where the glass ribbon contacts the conveying roller. Therefore, the dimension in the width direction of the portion of the glass ribbon where the scribe line is not formed can be shortened. As a result, the amount of scattering of the glass powder when the glass ribbon is broken along the scribe line in the cutting step can be reduced.

In this method, when the strength of the contact portion where the glass ribbon contacts the conveying roller is reduced, the positions of the start point and the end point of the scribe line may be changed to positions closer to the center side in the width direction than the contact portion.

In this way, by changing the positions of the start point and the end point of the score line, the score line does not interfere with the contact portion where the glass ribbon contacts the conveying roller. Therefore, even when the strength of the contact portion where the glass ribbon contacts the conveying roller is reduced as the conveying roller conveys the glass ribbon in the forming process, it is possible to reliably suppress the occurrence of breakage of the glass ribbon starting from the contact portion where the glass ribbon contacts the conveying roller. For example, the surface of the conveying roller is damaged by contact with the glass ribbon with use over time, and is in a state of fluffing and adhesion of glass powder. Therefore, the strength of the contact portion where the glass ribbon contacts the conveying roller is reduced due to damage or the like. In this state, if the scribe line passes through the contact portion where the glass ribbon contacts the conveying roller as described above, the glass ribbon may be damaged from the contact portion as a starting point. In the present invention, in this case, the scribing position of the scribing line is changed so that the scribing line does not interfere with the contact portion where the glass ribbon contacts the conveying roller.

In this method, when the strength of the contact portion of the glass ribbon with the conveying roller is restored, the positions of the start point and the end point of the score line may be returned to the positions between the contact portion of the glass ribbon with the cooling roller and the contact portion of the glass ribbon with the conveying roller.

In this way, the positions of the start point and the end point of the scribe line that have been temporarily changed are returned to the initial positions. This can suppress the occurrence of a longitudinal crack in the glass ribbon from the contact portion of the glass ribbon with the conveying roller and the contact portion of the glass ribbon with the cooling roller as starting points in the forming step and the cutting step, and can reduce the amount of scattering of glass powder when the glass ribbon is broken in the cutting step, as in the conventional case. In this case, as a method of recovering the strength of the contact portion where the glass ribbon contacts the conveying roller, for example, the conveying roller may be replaced.

Effects of the invention

According to the present invention, it is possible to reduce the amount of scattering of glass powder when breaking the glass ribbon along the scribe line while suppressing the occurrence of longitudinal cracks in the glass ribbon until the glass ribbon is formed and the glass plate is cut.

Drawings

Fig. 1 is a schematic view showing main steps of a method for producing a glass plate according to an embodiment of the present invention.

Fig. 2 is a front view showing a schematic configuration of a manufacturing apparatus used for carrying out the method of manufacturing a glass plate according to the embodiment of the present invention.

Fig. 3 is a vertical cross-sectional side view showing a schematic configuration of a manufacturing apparatus used in the implementation of the method for manufacturing a glass plate according to the embodiment of the present invention.

Fig. 4 is an enlarged cross-sectional plan view of a main portion of a glass ribbon showing a state in which the cutting step of the method for producing a glass plate according to the embodiment of the present invention is being performed.

Fig. 5 is an enlarged cross-sectional plan view of a main portion of a glass ribbon showing another state in which the cutting step of the method for producing a glass sheet according to the embodiment of the present invention is being performed.

Fig. 6 is a front view showing a schematic configuration of a manufacturing apparatus after the manufacturing method of a glass plate according to the embodiment of the present invention is performed.

Fig. 7 is a front view showing a schematic configuration of a manufacturing apparatus used in the implementation of the method for manufacturing a glass plate according to the embodiment of the present invention.

Detailed Description

Hereinafter, a method for manufacturing a glass plate according to an embodiment of the present invention will be described with reference to the drawings.

As shown in fig. 1, the method for producing a glass sheet according to the present embodiment includes, roughly classified, a forming step A1 of forming a glass ribbon by an overflow down-draw method and a cutting step A2 of cutting a glass sheet from the formed glass ribbon. In the forming step A1, an end portion cooling process of cooling the end portion in the width direction of the glass ribbon and a conveyance process of conveying the glass ribbon downward are performed. In the cutting step A2, a scribing process for scribing a scribe line on the glass ribbon and a breaking process for breaking the glass ribbon along the scribe line are performed.

Fig. 2 and 3 illustrate a glass plate manufacturing apparatus 1 for performing the forming step A1 and the cutting step A2. As shown in the above figures, the glass sheet manufacturing apparatus 1 includes a cooling roll 3 disposed directly below the forming body 2 and cooling the widthwise end portion of the glass ribbon G, and a conveying roll 4 disposed below the cooling roll 3 and conveying the glass ribbon G downward. The manufacturing apparatus 1 further includes a scoring blade 5 configured to score a score line S in a position below the conveying roller 4 with respect to the glass ribbon G conveyed in the forward and downward direction, and a breaking device 6 configured to break the glass ribbon G along the scored score line S.

The cooling roll 3 is a cantilever roll disposed in the inner space of the molding furnace together with the molded body 2. The pair of cooling rollers 3 is provided on the left and right in the front view shown in fig. 2, and these cooling rollers 3 sandwich the glass ribbon G from both the front and rear sides in the side view shown in fig. 3. The conveying rollers 4 are disposed in, for example, a plurality of stages (one stage in the drawing) above and below (including the cooling zone) in the internal space of the annealing furnace. The conveyance rollers 4 are attached to the left and right sides of the roller shaft 4x in the side view shown in fig. 2, and these conveyance rollers 4 nip the glass ribbon G from the front and rear sides in the side view shown in fig. 3. When the conveying rolls 4 are arranged in a plurality of stages, the scribing line S is formed below the lowermost conveying roll 4. The glass ribbon G may not be pinched by all the stages of the conveying rollers 4, but may be pinched by at least one stage of the conveying rollers 4.

The method for producing a glass plate according to the present embodiment will be described in detail below.

As shown in fig. 2, in the forming step A1, the conveyance roller 4 is positioned on the widthwise center side of the cooling roller 3. In the forming step A1, a contact portion G1 (hereinafter, referred to as a first contact portion G1) where the glass ribbon G contacts the conveying roller 4 is located on the center side in the width direction of a contact portion G2 (hereinafter, referred to as a second contact portion G2) where the glass ribbon G contacts the cooling roller 3. In fig. 2, the first contact portions G1 are illustrated as striped regions marked with cross-hatching with relatively large pitches, and the second contact portions G2 are illustrated as striped regions marked with cross-hatching with relatively small pitches. In this case, even if the conveyance roller 4 and the cooling roller 3 overlap each other in the width direction, the first contact portion G1 and the second contact portion G2 do not overlap each other in the width direction, unlike the illustration.

In the cutting step A2, a scribe line S is scribed on the glass ribbon G formed in the forming step A1. Specifically, since the glass ribbon G is conveyed downward, the scoring blade 5 is moved obliquely downward with respect to the width direction on the front surface side of the glass ribbon G. As a result, as shown in the drawing, a straight scribe line S is scribed on the glass ribbon G along the width direction (horizontal direction). On the rear surface side of the glass ribbon G, a member corresponding to a platform that receives the pressing force of the scoring blade 5, a backup roller that moves in synchronization with the scoring blade 5, and the like are disposed (not shown).

The start point S1 and the end point S2 of the scribe line S formed in the glass ribbon G are located between the first contact portion G1 and the second contact portion G2. Thus, the scribe line S passes through (crosses) the first contact portion G1 but does not reach the second contact portion G2. The second contact portion G2 is visually recognizable because it has irregularities due to its uneven surface, but the first contact portion G1 may be visually recognizable or may not be visually recognizable.

Fig. 4 is a cross-sectional plan view (with hatching omitted) showing a main portion of the glass ribbon G on which the scribing line S is formed by the scribing blade 5. In the present embodiment, a scribing tool is used as the scribing blade 5, but a scribing wheel or the like may be used instead. As shown in the figure, the width direction end Gx of the glass ribbon G has a larger plate thickness than the width direction center side Gy. The glass ribbon G has a thickness at the widthwise center Gy side that is the same as the widthwise center and has a uniform thickness over the entire length. A plate thickness varying portion Gz in which the plate thickness gradually becomes thinner as it moves to the widthwise center side is formed between the widthwise end Gx of the glass ribbon G and the widthwise center side Gy.

In the illustrated example, the first contact portion G1 is located on the widthwise central side portion Gy of the glass ribbon G. The second contact portion G2 is a portion of the widthwise end Gx of the glass ribbon G that the cooling roll 3 contacts. In the illustrated example, the start point S1 and the end point S2 of the scribe line S are located near the width direction center side Gy of the glass ribbon G.

The width direction separation dimension L1 from the start point S1 and the end point S2 of the scribe line S to the first contact portion G1 is preferably 10mm or more, and the width direction separation dimension L2 from the start point S1 and the end point S2 of the scribe line S to the second contact portion G2 is preferably 10mm or more. When the dimension L1 is less than 10mm, the dimension in the width direction of the portion of the glass ribbon G where the scribe line S is not formed becomes excessively long, and a large amount of glass frit is scattered when breaking. On the other hand, if the dimension L2 is less than 10mm, the start point S1 and the end point S2 of the score line S are too close to the second contact portion G2, and there is a possibility that a longitudinal crack may occur in the glass ribbon G from the second contact portion G2 when the score line S is formed. Therefore, if the dimensions L1 and L2 are within the above numerical range, these problems can be avoided.

As shown in fig. 5, the start point S1 and the end point S2 of the scribing line S may be located at the thickness variation portion Gz of the glass ribbon G, but in this case, the thickness of the thickness variation portion Gz is likely to vary, and therefore the scribing blade 5 is worn due to variation in the depth of the scribing line S, and the life of the scribing blade 5 is shortened. From the viewpoint of preventing this, it is preferable that the start point S1 and the end point S2 of the scribing line S be positioned on the width direction center side portion Gy of the glass ribbon G.

In the cutting step A2, after the scribing line S is scribed, the glass ribbon G is broken along the scribing line S by the breaking device 6, and the glass plate GP is cut as shown in fig. 6. The breaking device 6 may be configured to break the glass ribbon G by bending it, or may be configured to break the glass ribbon by pushing a striking tool (e.g., blade) against a portion of the scribe line S from the rear surface side.

According to the method for manufacturing a glass plate of the present embodiment described above, the following effects are obtained. The first contact portion G1 and the second contact portion G2 of the glass ribbon G do not overlap in the width direction. Therefore, the surface of the conveying roller 4 is not affected by the irregularities of the second contact portion G2. This prevents a problem such as entry of glass frit into the surface of the conveying roller 4, and suppresses a decrease in the strength of the first contact portion G1. As a result, it is possible to suppress the occurrence of a vertical crack in the glass ribbon G starting from the first contact portion G1 when the glass ribbon G is conveyed by the conveyance roller 4 in the forming step A1.

Further, the second contact portion G2 of the glass ribbon G has low strength because the surface thereof is formed with irregularities. However, the scribe line S does not reach the second contact portion G2. Therefore, the second contact portion G2 is less susceptible to the influence of the scribing line S. As a result, it is possible to suppress the occurrence of vertical cracks in the glass ribbon G from the second contact portion G2 as a starting point when the score line S is cut in the cutting step A2. On the other hand, the scribe line S passes through the first contact portion G1. Therefore, the width dimension of the glass ribbon G at the portion where the scribe line S is not formed can be shortened. As a result, the amount of scattering of the glass frit when the glass ribbon G is broken along the scribe line S in the cutting step A2 can be reduced.

The method for manufacturing a glass plate according to the present embodiment performs the following processes in addition to the above-described processes.

While the cutting step A2 is repeated for the glass ribbon G formed in the forming step A1, the strength of the first contact portion G1 of the glass ribbon G may be reduced. This is because the surface of the conveying roller 4 becomes fluffy due to the occurrence of contact damage or the like with use over time, and also becomes a state where glass frit adheres, and the conveying roller 4 in this state causes damage or the like to the first contact portion G1. As a result of the strength of the first contact portion G1 of the glass ribbon G being reduced, the glass ribbon G may be damaged. When such a decrease in strength or breakage occurs, as shown in fig. 7, the positions of the start point S1 and the end point S2 of the scribe line S formed in the glass ribbon G are changed to positions closer to the center in the width direction than the first contact portion G1. In this case, the widthwise separation dimension L3 from the start point S1 and the end point S2 of the scribe line S to the first contact portion G1 is preferably 10 to 100mm. In this way, the scribing line S scribed on the glass ribbon G does not interfere with the first contact portion G1, and therefore, the glass ribbon G can be reliably prevented from being damaged from the first contact portion G1.

While the cutting step A2 is performed in this state, the strength of the first contact portion G1 of the glass ribbon G may be restored to such an extent that breakage of the glass ribbon G from the first contact portion G1 does not occur. As a method for recovering the strength of the first contact portion G1, for example, the conveying roller 4 may be replaced. In this case, the positions of the start point S1 and the end point S2 of the scribe line S are returned to the positions explained with reference to fig. 4 or 5. In this way, as before, breakage of the glass ribbon G from the first contact portion G1 and the second contact portion G2 can be suppressed, and the amount of scattering of glass frit at the time of breaking can be reduced.

In the above embodiment, the glass ribbon G is formed by the overflow downdraw method in the forming step A1, but the glass ribbon G may be formed by another downdraw method such as a slit downdraw method.

Description of the reference numerals

1. Glass plate manufacturing device

3. Cooling roller

4. Carrying roller

A1 Shaping step

A2 Cutting-out process

G glass ribbon

G1 Contact part (first contact part) of the glass ribbon with the carrying roller

G2 Contact portion (second contact portion) of glass ribbon with cooling roll

GP glass plate

End part of Gx glass ribbon in width direction

S-shaped scribing line

S1 starting point of scribing line

S2, end point of scribing line.

Claims

1. A method for producing a glass sheet, comprising a forming step of forming a glass ribbon by a down-draw method and a cutting step of cutting a glass sheet from the formed glass ribbon,

in the forming step, a process of cooling the widthwise end portion of the glass ribbon by the cooling roll and a process of conveying the glass ribbon downward by the conveying roll disposed below the cooling roll are performed,

in the cutting step, a process of scribing a score line at a position lower than the conveying roller with respect to the glass ribbon conveyed downward and a process of breaking the glass ribbon along the score line are performed,

the method for manufacturing a glass sheet is characterized in that,

a contact portion where the glass ribbon contacts the conveying roller is positioned on the center side in the width direction of the contact portion where the glass ribbon contacts the cooling roller,

the start point and the end point of the score line are located between a contact portion of the glass ribbon with the conveying roller and a contact portion of the glass ribbon with the cooling roller,

the separation dimension in the width direction from the start point and the end point of the score line to the contact portion where the glass ribbon contacts the conveying roller is 10mm or more, and the separation dimension in the width direction from the start point and the end point of the score line to the contact portion where the glass ribbon contacts the cooling roller is 10mm or more.

2. The method for producing glass sheet according to claim 1,

when the strength of a contact portion where the glass ribbon contacts the conveying roller is reduced, the positions of the start point and the end point of the score line are changed to positions separated from the contact portion toward the center side in the width direction by a distance of 10mm to 100mm.

3. The method for producing glass sheet according to claim 2,

when the strength of the contact portion of the glass ribbon with the conveying roller is restored, the positions of the start point and the end point of the score line are returned to the positions between the contact portion of the glass ribbon with the cooling roller and the contact portion of the glass ribbon with the conveying roller.