JP7804257B2 - Glass plate manufacturing method and manufacturing device - Google Patents

Description

The present invention relates to a method and apparatus for manufacturing glass sheets, in which a glass ribbon moving downward in a vertical position is cut along its width at a standard cutting length to obtain glass sheets.

As is well known, in the field of glass sheet manufacturing, glass sheets are cut from a glass ribbon that has been formed by the downdraw method and is moving downward. A specific example of a method and apparatus for manufacturing glass sheets in this manner is disclosed in Patent Document 1.

The apparatus disclosed in the document comprises a scribing means for forming a scribe line on a glass ribbon moving downward in a vertical position, a breaking bar (called a fulcrum bar in the document) that is pressed against the scribe line formation area of the glass ribbon, and a support means (called a breaking arm in the document) that supports the glass ribbon below the scribe line. The method disclosed in the document for cutting out a glass sheet using this apparatus involves first forming a scribe line along the width direction of the glass ribbon with the scribing means, and then pressing the breaking bar against the scribe line formation area of the glass ribbon. Next, the support means, which is supporting the glass ribbon, is operated to bend the scribe line formation area using the breaking bar as a fulcrum. This bends and breaks the glass ribbon along the scribe line, and a glass sheet is cut out from the glass ribbon.

JP 2018-90446 A

However, if a cutting defect occurs during the cutting process described above, damage such as cracks or chips may occur at the bottom end of the glass ribbon remaining after the glass sheets are cut and separated. If such damage occurs and the glass ribbon is cut again at the same standard cutting length as when no damage occurs, there is a risk of a vertical crack occurring in the glass ribbon during the cutting process, in which the damage propagates upward. If such a vertical crack propagates upward beyond the cutting position of the glass ribbon (e.g., the scribe line), it may become impossible to cut out normal, undamaged glass sheets for an extended period of time. Furthermore, in the worst case scenario, the vertical crack may lead to damage to the entire glass ribbon over time, ultimately making it impossible to cut out glass sheets from the glass ribbon at all.

The objective of the present invention is to reliably prevent vertical cracks from occurring in a glass ribbon when cutting glass sheets from the glass ribbon.

(1) The present invention, which was devised to solve the above-mentioned problems, is a method for manufacturing a glass sheet, which includes a cutting process in which a glass ribbon moving downward in a vertical position is cut along its width direction at a standard cutting length to obtain a glass sheet, and is characterized in that it includes a determination process in which a portion including at least one of the lower end of the glass ribbon and the upper end of the glass sheet after cutting in the cutting process is used as the determination object and determines whether or not the determination object is damaged, and if the determination process determines that the determination object is damaged, in the next cutting process, the glass ribbon is cut at an extended cutting length longer than the standard cutting length.

When damage occurs at the lower end of the glass ribbon after cutting in the cutting process, damage often also occurs at the upper end of the glass sheet cut and separated from the glass ribbon at a position corresponding to the damage in the glass ribbon. Therefore, in the above configuration, to determine whether or not the lower end of the glass ribbon after cutting in the cutting process is damaged, the determination process determines whether or not the target is damaged, using at least one of the lower end of the glass ribbon and the upper end of the glass sheet after cutting in the cutting process as the target. If the determination process determines that the target is damaged, the glass ribbon is cut at an extended cutting length longer than the standard cutting length in the next cutting process, so that the lower end where the damage occurred is sufficiently separated downward from the cutting position of the glass ribbon in the next cutting process. This reliably prevents vertical cracks from occurring in the glass ribbon beyond the cutting position of the glass ribbon.

(2) In the configuration of (1) above, it is preferable that in the judgment process, the object to be judged is measured by a sensor and the presence or absence of damage to the object to be judged is determined based on the measurement results.

In this way, it is possible to automatically determine whether the object being evaluated is damaged or not.

(3) In the configuration (2) above, it is preferable that the sensor measures the widthwise end of the object to be judged.

The widthwise ends of a glass ribbon typically include ears that are thicker than the widthwise center. If the glass ribbon is cut (especially broken) without ears near the cutting position, vertical cracks that extend beyond the cutting position are likely to occur in the glass ribbon. Therefore, as in the above configuration, it is preferable for the sensor to measure the widthwise end of the glass ribbon to determine whether or not it is damaged.

(4) In the configuration (2) or (3) above, it is preferable that the sensor measures the widthwise ends and widthwise center of the object to be judged.

Even when cutting (particularly breaking) a glass ribbon while there is damage in the widthwise center near the cutting position, a vertical crack may occur in the glass ribbon that extends beyond the cutting position. Therefore, as in the above configuration, it is preferable for the sensor to measure the widthwise ends and widthwise center of the object to be evaluated in order to determine whether or not there is damage in the widthwise center as well as the widthwise ends of the object to be evaluated.

(5) In any one of the above configurations (1) to (4), it is preferable that the value obtained by subtracting the standard cutting length from the extended cutting length is 0.05 m or more and 4.0 m or less.

If the value obtained by subtracting the standard cutting length from the extended cutting length, i.e., (extended cutting length - standard cutting length), is set to 0.05 m or more, the area where the breakage has occurred can be sufficiently separated downward from the cutting position of the glass ribbon. On the other hand, if (extended cutting length - standard cutting length) is set to 4.0 m or less, it is possible to prevent the cutting length from being unduly long, making it easier to secure space during cutting.

(6) In any one of the above configurations (1) to (4), it is preferable that the extended cut length is 1.02 times or more and 4.1 times or less the standard cut length.

If the extended cutting length is 1.02 times or more the standard cutting length, the damaged portion can be sufficiently separated downward from the cutting position of the glass ribbon. On the other hand, if the extended cutting length is 4.1 times or less the standard cutting length, it is possible to prevent the cutting length from becoming unduly long, making it easier to secure space during cutting.

(7) In any one of the configurations (1) to (6) above, in the cutting process, the length of the extended cutting length may be adjusted depending on the type of damage to be determined.

In this way, the length of the glass sheet cut to the extended cutting length can be set to the optimal length depending on the type of breakage. Therefore, even if the glass sheet cut to the extended cutting length is discarded, glass waste can be minimized.

(8) In the configuration of (7) above, in the cutting process, the length of the extended cutting length may be adjusted depending on at least one of the position and size of the damage to be determined.

When considering the size of the damage as a characteristic of the breakage, for example, the extended cut length can be increased if the size of the breakage is large, and decreased if the size of the breakage is small. Furthermore, when considering the location of the breakage as a characteristic of the breakage, for example, the extended cut length can be increased if the location of the breakage is likely to have an adverse effect, and decreased if the location of the breakage is unlikely to have an adverse effect. In other words, the length of the glass sheet cut to the extended cut length can be set to an optimal length depending on the location and size of the breakage. Therefore, even if glass sheets cut to the extended cut length are discarded, glass waste can be minimized.

(9) In any one of the above configurations (1) to (8), the cutting process includes a scribing process for forming a scribe line on the glass ribbon along its width direction, and a bending and splitting process for cutting out a glass sheet by bending and splitting the glass ribbon along the scribe line while supporting the glass ribbon below the scribe line with a support means, and it is preferable that in the bending and splitting process, a bending and splitting bar is pressed against the scribe line formation area of the glass ribbon (hereinafter referred to as the scribe line formation area).

This makes it easy to cut the glass ribbon along its width. In the cutting process, the glass ribbon can also be cut by laser cleaving or laser melting, but the setting of cutting conditions tends to be more complicated than with the above configuration.

(10) In the configuration of (9) above, the bending and splitting process is a process of bending and splitting the glass ribbon by operating the support means while pressing the bending and splitting bar against the scribe line formation area, and bending the scribe line formation area vertically using the bending and splitting bar as a fulcrum, and when cutting the glass ribbon at the extended cutting length, it is preferable to slow down the operating speed of the support means for bending the scribe line formation area compared to when cutting the glass ribbon at the standard cutting length.

When cutting a glass ribbon to an extended cutting length, the glass ribbon contains breakage. Therefore, from the perspective of suppressing vertical cracks in the glass ribbon, it is preferable to safely cut the glass ribbon by slowing the operating speed of the support means below normal speed, as in the above configuration.

(11) In the configuration of (9) above, the bending and splitting process is a process of bending and splitting the glass ribbon by operating the support means to bend the scribe line formation area in the vertical direction and pressing a bending bar against the scribe line formation area, and when cutting the glass ribbon at the extended cutting length, it is preferable to slow down at least one of the operating speed of the support means for bending the scribe line formation area and the operating speed of the bending bar pressed against the scribe line formation area compared to when cutting the glass ribbon at the standard cutting length.

When cutting a glass ribbon to an extended cutting length, the glass ribbon contains breakage. Therefore, from the perspective of suppressing vertical cracks in the glass ribbon, it is preferable to safely cut the glass ribbon by slowing down at least one of the operating speed of the support means and the operating speed of the breaking bar, as in the above configuration, compared to normal.

(12) In any one of the configurations (9) to (11) above, in the cutting process, if there is a break in the glass ribbon, it is preferable to set the extended cutting length so that the broken portion is positioned below the contact position of the support means with the glass ribbon.

This ensures that the support means does not come into contact with broken portions of the glass ribbon, which could cause vertical cracks in the glass ribbon.

(13) The present invention, which was devised to solve the above-mentioned problems, is a glass plate manufacturing apparatus equipped with a cutting device that cuts a glass ribbon moving downward in a vertical position along its width direction at a standard cutting length to obtain a glass plate, and is equipped with a judgment unit that judges whether or not the object to be judged is damaged, using a portion including at least one of the lower end of the glass ribbon and the upper end of the glass plate after cutting by the cutting device as the object to be judged, and a control unit that adjusts the cutting length of the glass ribbon based on the judgment result of the judgment unit, and is characterized in that when the judgment unit judges that the object to be judged is damaged, the control unit sets the cutting length of the glass ribbon by the cutting device for the next time to an extended cutting length that is longer than the standard cutting length.

In this way, you can enjoy the same effects as the corresponding configuration already described.

According to the present invention, it is possible to reliably prevent vertical cracks from occurring in the glass ribbon when cutting glass sheets from the glass ribbon.

1 is a schematic side view showing the overall configuration of a glass sheet manufacturing apparatus according to a first embodiment of the present invention. 1 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a first embodiment of the present invention. 1 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a first embodiment of the present invention. 1 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a first embodiment of the present invention. 1 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a first embodiment of the present invention. 1 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a first embodiment of the present invention. 1 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a first embodiment of the present invention. 1 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a first embodiment of the present invention. 1 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a first embodiment of the present invention. FIG. 4 is a schematic front view (viewed from direction A in FIG. 1 ) showing a main part of a glass plate manufacturing apparatus according to a third embodiment of the present invention. FIG. 10 is a schematic front view (viewed from the direction A in FIG. 1 ) showing a main part of a glass plate manufacturing apparatus according to a fourth embodiment of the present invention. FIG. 10 is a schematic front view (viewed from direction A in FIG. 1 ) showing a main part of a glass plate manufacturing apparatus according to a fifth embodiment of the present invention. FIG. 10 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a fifth embodiment of the present invention. FIG. 10 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a fifth embodiment of the present invention. FIG. 10 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a fifth embodiment of the present invention. FIG. 10 is a schematic front view (viewed from direction A in FIG. 1 ) illustrating an implementation status of a glass plate manufacturing method according to a fifth embodiment of the present invention. FIG. 10 is a schematic front view (viewed from the direction A in FIG. 1 ) showing a main part of a modified example of the glass sheet manufacturing apparatus according to the fifth embodiment of the present invention.

The glass plate manufacturing method and manufacturing apparatus according to an embodiment of the present invention will be described below with reference to the drawings. Note that in each embodiment, corresponding components are given the same reference numerals, and duplicate explanations may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described can be applied to the remaining portions of that configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of multiple embodiments can also be partially combined together even if not explicitly stated, as long as there are no particular problems with the combination.

(First embodiment)
As shown in Fig. 1 , the glass sheet manufacturing apparatus according to the first embodiment of the present invention includes a processing device 1 for a glass ribbon G, a cutting device 2, and a determination device 3. In this embodiment, the glass ribbon G is configured to move downward in a vertical position (preferably a vertical position) from the processing device 1 to the cutting device 2.

The processing device 1 includes a forming zone 11 for continuously forming the glass ribbon G, a heat treatment zone 12 for heat treating (slowly cooling) the glass ribbon G, a cooling zone 13 for cooling the glass ribbon G to near room temperature, and a conveying device 14 consisting of roller pairs R arranged in multiple upper and lower stages in each of the forming zone 11, heat treatment zone 12, and cooling zone 13.

The forming zone 11 and the heat treatment zone 12 are composed of furnaces with walls surrounding the transport path of the glass ribbon G, and heating devices such as heaters that adjust the temperature of the glass ribbon G are arranged at appropriate locations within the furnace. On the other hand, the cooling zone 13 is not surrounded by walls around the transport path of the glass ribbon G, and is open to the ambient atmosphere at room temperature, and no heating devices such as heaters are arranged therein.

The internal space of the forming zone 11 is equipped with a forming body 15 that forms a glass ribbon G from molten glass Gm using the overflow downdraw method. The molten glass Gm supplied to the forming body 15 overflows from a groove (not shown) formed in the top 15a of the forming body 15. This overflowing molten glass Gm flows down both side surfaces 15b, which have a wedge-shaped cross section, of the forming body 15 and joins at the bottom end. This allows a sheet-shaped glass ribbon G to be continuously formed.

The internal space of the heat treatment zone 12 has a predetermined temperature gradient downward. The glass ribbon G in a vertical position is heat-treated (slowly cooled) so that its temperature decreases as it moves downward through the internal space of the heat treatment zone 12. This heat treatment reduces internal strain in the glass ribbon G. The temperature gradient in the internal space of the heat treatment zone 12 is adjusted, for example, by a heating device installed on the inner wall surface of the heat treatment zone 12.

The multiple roller pairs R that make up the conveying device 14 clamp both widthwise ends of the glass ribbon G in a vertical position from both the front and back. The uppermost roller pair R arranged in the forming zone 11 is a cooling roller, and is sometimes called an edge roller. Note that, in the internal space of the heat treatment zone 12, the multiple roller pairs R may include ones that do not clamp the side ends of the glass ribbon G. In other words, the distance between the opposing roller pairs R may be greater than the thickness of both widthwise ends of the glass ribbon G, allowing the glass ribbon G to pass between the roller pairs R.

In this embodiment, both widthwise ends of the glass ribbon G produced by the processing device 1 have portions (hereinafter referred to as ear portions) that are thicker than the widthwise central portion due to factors such as shrinkage during the molding process.

The cutting device 2 is configured to sequentially cut glass sheets g from the glass ribbon G by cutting the glass ribbon G in a vertical position below the processing device 1 in the width direction at predetermined lengths (standard cutting length L0). Here, the width direction is a direction perpendicular to the longitudinal direction (conveying direction) of the glass ribbon G, and in this embodiment, it essentially coincides with the horizontal direction.

The cutting device 2 comprises a scribing device 21 and a breaking device 22. The scribing device 21 and the breaking device 22 are configured to perform cutting-related operations while moving downward at the same speed as the glass ribbon G.

The scribing device 21 is equipped with a wheel cutter 23 that forms a scribe line S by running along the width direction (in Figure 1, perpendicular to the paper surface) on the first main surface of the glass ribbon G as it moves downward at the scribing position P1, and a support rod 24 that is long in the width direction and supports the portion of the glass ribbon G along which the wheel cutter 23 runs from the second main surface side.

The wheel cutter 23 is formed in a disk shape and has a blade (edge) on the periphery that rotates when the vehicle is running.

The support rod 24 has a contact surface that contacts the portion along which the wheel cutter 23 travels. The contact surface of the support rod 24 protrudes from both widthwise ends of the glass ribbon G. The wheel cutter 23 and support rod 24 are configured to move downward together with the glass ribbon G, forming a scribe line S across the entire width or a portion of the width of the glass ribbon G. In this embodiment, a scribe line S is also formed on the ear portion.

The slicing device 22 slicingly splits the glass ribbon G moving downward along the scribe line S at a slicing position P2 located below the scribing position P1, and cuts out the portion of the glass ribbon G below the scribe line S (the lower region of the glass ribbon G) as a glass sheet g. In this embodiment, the slicing device 22 includes a slicing bar 25 that contacts the scribe line formation region Sx from the second main surface side, and a support means 26 that supports the glass ribbon G below the slicing position P2. Note that in this embodiment, because cutting-related operations are performed while the glass ribbon G is moved downward, strictly speaking, the scribing position P1 and the slicing position P2 are regions that have widths in the vertical direction.

The cleaving bar 25 has a contact surface with a convex cross section (e.g., semicircular or curved) that contacts the second main surface side of the scribe line formation region Sx. The contact surface of the cleaving bar 25 extends beyond both widthwise ends of the glass ribbon G. Here, the scribe line formation region Sx is a region that includes the scribe line S, and is, for example, a region between two portions of the glass ribbon G that are 80 to 120 mm above and below the scribe line S.

The support means 26 includes a plurality of chucks 27 that grip both widthwise ends of the glass ribbon G, and an arm 28 (see Figure 2) that holds the plurality of chucks 27.

While supporting the glass ribbon G, the support means 26 is configured to change its position from the basic position shown by the dotted line in FIG. 1 to the inclined position shown by the solid line in the same figure. This change in the position of the support means 26 is achieved by the rotational movement of the support means 26 (movement in the direction B in FIG. 1) around the position of the breaking bar 25 (the position shown by the solid line in FIG. 1). Furthermore, the change in position of the support means 26 is achieved while it is moving downward at the same speed as the glass ribbon G. Then, by the above-mentioned rotational movement, the support means 26 curves the scribe line formation region Sx in the vertical direction so that the first main surface side is convex. This rotational movement of the support means 26, in cooperation with the movement of pressing the breaking bar 25 against the scribe line formation region Sx, serves to break the glass ribbon G along the scribe line S.

The wheel cutter 23, support rod 24, breaking bar 25, and support means 26 are configured to perform their respective functions while moving downward at the same speed as the glass ribbon G. The wheel cutter 23, support rod 24, and breaking bar 25 are configured to move along the thickness direction of the glass ribbon G between an operating position where they perform their respective functions and a retracted position where they are retracted away from the glass ribbon G. The movement of each of these components along the thickness direction is performed while moving downward at the same speed as the glass ribbon G. The operating position of the breaking bar 25 is indicated by a solid line in Figure 1, and the retracted position is indicated by a dotted line in the same figure. Meanwhile, the operating position of the wheel cutter 23 and support rod 24 is indicated by a dotted line in Figure 1, and the retracted position is indicated by a solid line in the same figure.

As shown in Figures 4, 5, 8, and 9, the determination device 3 is a device for determining whether or not damage has occurred in the lower end Gt of the glass ribbon G and the upper end gt of the glass sheet g (standard glass sheet gx or extended glass sheet gy) after cutting by the cutting device 2. The determination target may be only either the lower end Gt of the glass ribbon G or the upper end gt of the glass sheet g. The reason why only the upper end gt of the glass sheet g may be the determination target is that, as shown in Figure 5, when damage D1 is present in the lower end Gt of the glass ribbon G, damage D2 often occurs at a position corresponding to the upper end gt of the glass sheet g. Therefore, the presence or absence of damage D2 in the upper end gt of the glass sheet g can be predicted based on the presence or absence of damage D1 in the lower end Gt of the glass ribbon G. The determination target may further include a portion of the glass ribbon G above the lower end Gt and/or a portion of the glass sheet g below the upper end gt.

In this embodiment, the determination device 3 includes a sensor 31, a determination unit 32, and a control unit 33.

The sensor 31 is composed of a thermograph that measures the temperature distribution of the test objects Gt, gt, and is disposed below the height of the wheel cutter 23 and above the lower end of the support means 26. In this embodiment, the sensor 31 is disposed below the height of the splitting bar 25 and above the lower end of the support means 26, and measures the temperature distribution across the entire width of the test objects Gt, gt. The sensor 31 is disposed at the widthwise center of the test objects Gt, gt, on one of the main surfaces of the test objects Gt, gt (the first main surface of the glass ribbon G), spaced apart from the main surface. The distance between the sensor 31 and the test objects Gt, gt can be set arbitrarily within a range that allows for non-contact measurement of the temperature distribution of the test objects Gt, gt (for example, in the range of 800 to 3000 mm). The sensor 31 may also be disposed on the other main surface of the test objects Gt, gt.

The determination unit 32 performs image analysis on the thermal image showing the temperature distribution captured by the sensor 31, and determines whether or not damage has occurred to the objects Gt, gt based on the results. Because the temperature differs between areas where glass is present and areas where no glass is present due to damage, etc., using a thermograph as the sensor 31 makes it possible to determine whether or not damage has occurred based on the temperature distribution. The determination unit 32 is configured as an information processing device, such as a personal computer.

Here, when the glass ribbon G is cut by breaking, not only does the glass ribbon G vibrate after cutting, but the glass sheet g may also vibrate due to vibration or shaking of the support means 26. Furthermore, if the glass ribbon G is thin or if the glass ribbon G is warped, the shaking of the glass ribbon G and glass sheet g after cutting may be significant. However, because the determination unit 32 determines whether or not damage has occurred in the determination objects Gt, gt from the temperature distribution measured by the sensor 31, it is less likely to be adversely affected by the shaking of the glass ribbon G and glass sheet g.

The control unit 33 adjusts the cut length of the glass ribbon based on the judgment result of the judgment unit 32. Specifically, if the judgment unit 32 determines that there is no damage to the judgment targets Gt and gt, the control unit 33 sets the cut length of the glass ribbon G to the standard cut length L0 by the cutting device 2 the next time, as shown in Figures 2 to 4. On the other hand, if the judgment unit 32 determines that there is damage to the judgment targets Gt and gt, the control unit 33 sets the cut length of the glass ribbon G to the extended cut length L1 by the cutting device 2 the next time, as shown in Figures 6 to 8. To perform cutting at the standard cut length L0 or the extended cut length L1, the control unit 33 issues control signals to the wheel cutter 23, support rod 24, breaking bar 25, support means 26, etc., according to the respective cut lengths L0 and L1. The cut lengths L0 and L1 are managed by the downward movement distance and/or movement time of the glass ribbon G.

Next, we will explain the method for manufacturing glass plates using the manufacturing apparatus configured as described above.

As shown in Figure 1, the glass plate manufacturing method according to this embodiment includes a forming process, a transporting process, and an evaluation process. The transporting process includes a heat treatment process, a cooling process, and a cutting process.

The forming process is a process in which a glass ribbon G is formed by the overflow downdraw method in the forming zone 11. In the forming process, the glass ribbon G may also be formed by other downdraw methods such as the redraw method or the slot downdraw method.

Here, the glass ribbon G and glass plate g have a widthwise length of 1000 to 3500 mm and a thickness of 100 to 2000 μm. The standard cutting length L0 of the glass ribbon G is 800 to 3000 mm. The extended cutting length L1 is longer than the standard cutting length L0, and the difference (L1 - L0) is preferably 0.05 m or more and 4.0 m or less, and more preferably 0.5 m or more and 1.5 m or less. Furthermore, the ratio (L1/L0) of the extended cutting length L1 to the standard cutting length L0 is preferably 1.02 to 4.1 or less, and more preferably 1.05 to 2.0 or less. Here, as shown in Figures 2 and 6, the standard cutting length L0 and the extended cutting length L1 each refer to the length from the position (upper end) of the scribe line S formed in the current (nth) cutting process to the position (lower end) of the scribe line S formed in the previous (n-1th) cutting process. Therefore, if the glass ribbon G is damaged, the position of the scribe line S, which is the reference for the cutting length, may be an imaginary position where no glass is present.

The conveying process is a process in which the formed glass ribbon G is conveyed downward by a pair of rollers R (conveying device).

The heat treatment process is a process in which the glass ribbon G that has undergone the forming process is subjected to heat treatment (slow cooling) while being transported in the heat treatment zone 12.

The cooling process is a process in which the glass ribbon G that has undergone the heat treatment process is cooled while being transported in the cooling zone 13.

The cutting process is a process in which the glass ribbon G that has undergone the cooling process is transported and cut widthwise using a cutting device 2 to cut out glass sheets g.

The cutting process includes a scribing process in which a scribe line S is formed on the glass ribbon G along its width direction, and a bending and breaking process in which the glass ribbon G is supported below the scribe line S by the chuck 27 of the support means 26, and the glass ribbon G is bent and broken along the scribe line S to cut out a glass plate g (standard glass plate gx or extended glass plate gy).

In the scribing process, first, the wheel cutter 23 and support rod 24 are moved from the retracted position to the operating position while the glass ribbon G is supported by the multiple chucks 27 of the support means 26. Next, as shown in Figure 2 or Figure 6, the wheel cutter 23, which has been moved to the operating position, is run across the first main surface of the glass ribbon G in the width direction to form a scribe line S.

After the scribing process is completed, the wheel cutter 23 and support rod 24 are moved from the operating position to the retracted position. In this case, the support of the glass ribbon G by the chuck 27 of the support means 26 continues even after the scribing process is completed. Here, at the time the scribing process is completed, the wheel cutter 23 and support rod 24 are at the same height as the scribe line S. Thereafter, as the glass ribbon G continues to move downward, the breaking bar 25 is held at the same height as the scribe line S, instead of the wheel cutter 23 and support rod 24, as shown in Figure 3 or Figure 7.

In the bending and splitting process, as shown in Figure 1, the bending and splitting bar 25 is moved from the retracted position to the working position, and the support means 26 is rotated as shown by arrow B. That is, in the bending and splitting process, the bending and splitting bar 25 is pressed against the first main surface of the scribe line formation region Sx, and the support means 26 is rotated, using the bending and splitting bar 25 as a fulcrum to bend the scribe line formation region Sx in the vertical direction so that the first main surface side is convex. As a result, as shown in Figure 4 or Figure 8, the glass ribbon G is bent and split along the scribe line S, and a glass sheet g is cut out.

The determination process is a process of performing image analysis on the thermal image showing the temperature distribution captured by the sensor 31 and determining whether or not damage has occurred in the objects Gt, gt based on the results. In this embodiment, if the determination process determines that damage has occurred in the objects Gt, gt, detailed information such as the location, shape, and size of the damage is also simultaneously determined from the thermal image. In this embodiment, the determination process is performed automatically by the determination unit 32.

One method for determining the extent of damage is to find the area of high-temperature areas in the image obtained by thermography that are above a predetermined temperature. In this case, for example, if the area of the high-temperature areas falls below a predetermined threshold, it can be determined that there is significant damage to the glass. This is because the areas where there is glass become hot, and the areas where there is no glass due to the damage become cold.

If the determination unit 32 determines that the determination targets Gt, gt are not damaged during the determination process, the control unit 33 sets the cut length of the glass ribbon G in the next cutting process to the standard cut length L0 and issues control signals corresponding to the standard cut length L0 to the wheel cutter 23, support rod 24, breaking bar 25, support means 26, etc. As a result, as shown in Figures 2 to 4, in the next cutting process, the glass ribbon G is bent and split widthwise at the standard cut length L0, resulting in a standard glass sheet gx cut at the standard cut length L0 as the glass sheet g. Specifically, as shown in Figure 2, at scribing position P1, a scribe line S is formed widthwise on the first main surface of the glass ribbon G using the wheel cutter 23 and support rod 24 at a position corresponding to the standard cut length L0. Thereafter, as shown in Figures 3 and 4, at breaking position P2, the glass ribbon G is bent and split widthwise at the standard cut length L0 using the breaking bar 25 and support means 26, resulting in a standard glass sheet gx. The cut-out standard glass plate gx becomes a glass original plate (mother glass plate) from which one or more product glass plates are obtained. In other words, if the cut-out standard glass plate gx is not broken, it is transported to subsequent processes including a process of cutting off the edge portions, a cleaning process, a testing process, a packaging process, etc.

On the other hand, as shown in FIG. 5, if the determination unit 32 determines during the determination process that the determination targets Gt and gt have breaks D1 and D2, the control unit 33 sets the cut length of the glass ribbon G in the next cutting process to the extended cut length L1 and issues control signals corresponding to the extended cut length L1 to the wheel cutter 23, support rod 24, breaking bar 25, support means 26, etc. As a result, as shown in FIGS. 6 to 8, during the next cutting process, the glass ribbon G is broken widthwise at the extended cut length L1, and an extended glass sheet gy cut at the extended cut length L1 is obtained as the glass sheet g. Specifically, as shown in FIG. 6, at scribing position P1, a scribe line S is formed widthwise on the first main surface of the glass ribbon G by the wheel cutter 23 and support rod 24 at a position corresponding to the extended cut length L1. 7 and 8 , at the breaking position P2, the glass ribbon G is broken widthwise by the breaking bar 25 and the support means 26 at the extended cutting length L1, and an extended glass sheet gy is cut out. The cut extended glass sheet gy is discarded because it is a defective product. Note that, if the determination unit 32 determines that the objects Gt, gt have breaks D1, D2, the glass sheet g including the object Gt is also discarded. In other words, if the determination unit 32 determines that the objects Gt, gt have breaks D1, D2, at least two glass sheets g are discarded consecutively. The glass sheets g are discarded, for example, by releasing the support by the chuck 27 of the support means 26 and dropping the glass sheets g into a recovery chamber located below the cutting chamber.

Here, as shown in Figure 9, if, after cutting the glass ribbon G at the extended cutting length L1, it is again determined in the assessment process that there are breaks D3 and D4 in the assessment targets Gt and gt, the glass ribbon G is also cut at the extended cutting length L1 in the next cutting process. On the other hand, if, after cutting the glass ribbon G at the extended cutting length L1, it is determined in the assessment process that there are no breaks in the assessment targets Gt and gt, the glass ribbon G is cut at the standard cutting length L0 in the next cutting process. Thereafter, the same operation is repeated while adjusting the cutting length of the glass ribbon G to either the standard cutting length L0 or the extended cutting length L1 depending on the results of the assessment process.

With the above configuration, if there is damage to the objects Gt, gt to be judged, the glass ribbon G is cut at an extended cutting length L1 that is longer than the standard cutting length L0. This allows the portion of the glass ribbon G where the damage is located to be sufficiently separated downward from the cutting position of the glass ribbon G (the scribe line formation area Sx). This reliably prevents vertical cracks from occurring in the glass ribbon G beyond the cutting position of the glass ribbon G.

The extended cutting length L1 is preferably set so that the portion of the glass ribbon G where the break D1 is located is positioned below the position where the glass ribbon G comes into contact with the lowest chuck 27 of the support means 26. This reliably prevents the glass ribbon G from being cracked vertically due to contact between the portion of the glass ribbon G where the break D1 is located and the chuck 27.

In this embodiment, the extended cut length L1 is a predetermined fixed value, but it may also be a variable value that changes depending on the size of the damage D1, D2 of the objects Gt, gt (such as the vertical length or area on the thermal image). In other words, if the size of the damage D1, D2 determined by the determination unit 32 is large, the extended cut length L1 may be increased, and if the size of the damage D1, D2 is small, the extended cut length L1 may be decreased. In this way, the length of the extended glass plate gy can be optimized according to the size of the damage, thereby reducing glass waste.

In the scribing process, as shown in FIG. 6, it is preferable to set the travel speed V1 of the wheel cutter 23 when cutting the glass ribbon G at the extended cutting length L1 slower than the travel speed V0 of the wheel cutter 23 when cutting the glass ribbon G at the standard cutting length L0 as shown in FIG. 2. Furthermore, in the bending and splitting process, as shown in FIG. 8, it is preferable to set the operating speed W1 (operating speed in the direction B in FIG. 1) of the support means 26 that curves the scribe line formation region Sx when cutting the glass ribbon G at the extended cutting length L1 slower than the operating speed W0 of the support means 26 that curves the scribe line formation region Sx when cutting the glass ribbon G at the standard cutting length L0 as shown in FIG. 4. This allows the glass ribbon G with breakage to be cut more safely at the extended cutting length L1, thereby more reliably suppressing vertical cracking of the glass ribbon G.

Second Embodiment
The glass sheet manufacturing apparatus and glass sheet manufacturing method according to the second embodiment of the present invention differ from the first embodiment in the bending and breaking step of bending and breaking the glass ribbon G. In the bending and breaking step in the first embodiment, the glass ribbon is bent and broken by rotating the support means 26 while the bending and breaking bar 25 is pressed against the scribe line formation region Sx, and bending the scribe line formation region Sx in the vertical direction with the bending and breaking bar 25 as a fulcrum. In contrast, in the bending and breaking step in the second embodiment, the glass ribbon is bent and broken by pressing the bending bar 25 against the scribe line formation region Sx while operating the support means 26 to bend the scribe line formation region Sx in the vertical direction. In other words, the timing of pressing the bending bar 25 and the timing of rotating the support means 26 differ from the first embodiment.

With this type of bending/splitting process, even if the glass ribbon G moving downward in a vertical position has warpage along its length (vertical direction) or its width direction, which is perpendicular to the length, the glass ribbon G can be properly bent and split without being adversely affected by the warpage. In other words, the glass ribbon G is less likely to be broken by cutting at its lower end, etc. Specifically, in this method, in the bending/splitting process after the scribing process, the scribe line formation region Sx of the glass ribbon G is first bent in the vertical direction. The forcible bending deformation that occurs in this region Sx at this time naturally eliminates the warpage. Next, by pressing the bending bar 25 against the curved scribe line formation region Sx in the state where the warpage has disappeared, the bending bar 25 makes uniform contact with the region Sx without localized contact. Since the glass ribbon G is bent and split while maintaining uniform contact with the bending bar 25, cutting errors are less likely to occur. Furthermore, since there is less need to consider cutting errors when folding and splitting, it becomes possible to operate the support means 26 at high speed, thereby shortening the tact time.

In this case, in the breaking process, when cutting the glass ribbon G at the extended cutting length L1, it is preferable to slow down at least one of the operating speed of the support means 26 that curves the scribe line formation region Sx and the operating speed of the breaking bar 25 that presses against the scribe line formation region Sx (the movement speed of the breaking bar 25 from the retracted position to the operating position in Figure 1) compared to when cutting the glass ribbon G at the standard cutting length L0. This allows the glass ribbon G with damage to be cut more safely at the extended cutting length L1, thereby more reliably suppressing vertical cracks in the glass ribbon G.

If the operating speed of the support means 26 when cutting at the extended cutting length L1 is X1 and the operating speed of the support means 26 when cutting at the standard cutting length L0 is X0, then it is preferable that X1/X0 be 10% to 90%. Furthermore, if the operating speed of the breaking bar 25 when cutting at the extended cutting length L1 is Y1 and the operating speed of the breaking bar 25 when cutting at the standard cutting length L0 is Y0, then it is preferable that Y1/Y0 be 10% to 90%.

(Third embodiment)
As shown in Figure 10, the glass sheet manufacturing apparatus and glass sheet manufacturing method according to the third embodiment differ from the above-described embodiments in that a plurality of sensors (thermographs) 31 (three in the illustrated example) are installed along the width direction. In this manner, the entire width of the objects Gt, gt can be measured more precisely than when a single sensor 31 is used to measure the entire width of the objects Gt, gt. Therefore, in the determination step, the determination unit 32 can more precisely determine whether or not the objects Gt, gt are damaged in the width direction. When a plurality of sensors 31 are installed, it is preferable to install a dedicated sensor 31 in at least three regions of the objects Gt, gt: one end in the width direction, a center in the width direction, and the other end in the width direction.

(Fourth embodiment)
As shown in FIG. 11 , the glass sheet manufacturing apparatus and glass sheet manufacturing method according to the fourth embodiment of the present invention differ from the above-described embodiments in that, in the determination process, the sensor 31 measures only the widthwise edge (ear portion) of the object to be determined (the lower end portion of the glass ribbon G) Gt.

In this embodiment, sensors 31 are installed on both arms 28 of the support means 26. In the illustrated example, one sensor 31 is installed on each arm 28 between the lowest chuck 27 and the second-lowest chuck 27. The determination unit 32, with the chucks 27 of the support means 26 open, measures the presence or absence of both widthwise edges of the test object Gt as it moves downward while passing between the chucks 27. The control unit 33 issues control signals to the wheel cutter 23, support rod 24, breaking bar 25, support means 26, etc. to initiate cutting-related operations a predetermined time after the determination unit 32 determines that both widthwise edges of the test object Gt are present. In other words, when there is damage to the widthwise edge of the test object Gt, the resulting cut length of the glass ribbon G (the length from the position (top end) of the scribe line S formed in the nth cutting step to the position (bottom end) of the scribe line S formed in the n-1th cutting step) is longer than when there is no damage. Therefore, even with this configuration, if it is determined in the evaluation process that the evaluation object Gt is damaged, in the next cutting process, the glass ribbon G will be cut to an extended cutting length longer than the standard cutting length.

In the above configuration, even if there is damage to the widthwise center of the glass ribbon G, if there is no damage to both widthwise end edges of the glass ribbon G, it is not determined that there is damage to the glass ribbon G. However, vertical cracks in the glass ribbon G are particularly likely to occur when the glass ribbon G is cut near the cutting position without both widthwise end edges of the glass ribbon G. Therefore, simply determining whether or not there is damage to both widthwise end edges of the glass ribbon G is effective in suppressing vertical cracks in the glass ribbon G. In addition, from the perspective of further suppressing vertical cracks, it is preferable to add a sensor to the above configuration to determine whether or not there is a widthwise center of the glass ribbon G.

Fifth Embodiment
As shown in FIG. 12 , the glass plate manufacturing apparatus and the glass plate manufacturing method according to the fifth embodiment of the present invention differ from the above-described embodiments in that a plurality of sensors 31 are arranged in the vertical direction, and in the determination process, the upper sensor 31 a and the lower sensor 31 b determine different objects to be determined.

For example, as shown in Figures 13 and 14, the judgment area (area surrounded by dotted line) Ja of the upper sensor 31a includes the entire widthwise area of the upper end gt of the glass plate g as the judgment target, and the judgment area (area surrounded by dotted line) Jb of the lower sensor 31b includes the entire widthwise area of the central portion gu of the glass plate g below the upper end gt as the judgment target.

With this configuration, as shown in Figures 13 and 14, if there is a large break D5 or D6 extending from the upper end gt to the center gu of the glass sheet g, the glass breakage is detected not only by the upper sensor 31a but also by the lower sensor 31b. When glass breakage is detected by the lower sensor 31b in this manner, the extended cutting length L1 is set to the first length. On the other hand, as shown in Figure 15, there may be cases where breakage D7 occurs only at the upper end gt of the glass sheet g, rather than a large break extending from the upper end gt to the center gu. In this case, glass breakage is detected only by the upper sensor 31a. When glass breakage is detected only by the upper sensor 31a in this manner, the extended cutting length L1 is set to the second length, which is shorter than the first length. Note that, as shown in Figure 16, there may be cases where breakage D8 occurs only at the center gu of the glass sheet g (in the illustrated example, at the widthwise end of the center gu). In this case, glass breakage is detected only by the lower sensor 31b. Even if glass breakage is detected only by the lower sensor 31b in this way, there may be small scratches or the like on the upper end gt of the glass plate g, and it is preferable to set the extended cutting length L1 to the first length (> second length).

For example, it is preferable that the vertical range of the judgment area Ja of the upper sensor 31a and the vertical range of the judgment area Jb of the lower sensor 31b are equal, or that the vertical range of the judgment area Ja of the upper sensor 31a be wider than the vertical range of the judgment area Jb of the lower sensor 31b. The vertical ranges of the judgment area Ja of the upper sensor 31a and the judgment area Jb of the lower sensor 31b are each preferably 0.5 to 10% of the standard cutting length L0 of the glass ribbon G, and more preferably 1 to 7%.

As shown in FIG. 17 , the judgment area (area surrounded by a dotted line) Jb of the lower sensor 31b may include the entire width of the lower end Gt of the glass ribbon G as the judgment target, and the judgment area (area surrounded by a dotted line) Ja of the upper sensor 31a may include the entire width of the central portion Gu of the glass ribbon G above the lower end Gt as the judgment target. In this case, as with the above, it is possible to distinguish between (1) major damage extending from the lower end Gt to the central portion Gu of the glass ribbon G, (2) damage only at the lower end Gt of the glass ribbon G, and (3) damage only at the central portion Gu of the glass ribbon G, and adjust the extended cutting length L1 accordingly. For example, in the case of major damage extending from the lower end Gt to the central portion Gu of the glass ribbon G and in the case of damage only at the central portion Gu of the glass ribbon G, the extended cutting length L1 may be set to a relatively long first length, and in the case of damage only at the lower end Gt of the glass ribbon G, the extended cutting length L1 may be set to a relatively short second length.

While this embodiment describes adjusting the extended cut length L1 according to the type of damage, specifically the vertical position of the damage, it is also possible to adjust the extended cut length L1 according to the widthwise position of the damage (or the vertical and widthwise positions). For example, if the location of the damage includes the widthwise ends, the extended cut length L1 may be set relatively long, and if the location of the damage is limited to the widthwise center, the extended cut length L1 may be set relatively short. Furthermore, the type of damage may include not only the location of the damage but also the size of the damage, and the extended cut length L1 may be adjusted taking the size of the damage into consideration. For example, if the size of the damage is large, the extended cut length L1 may be set relatively long, and if the size of the damage is small, the extended cut length L1 may be set relatively short. Furthermore, the type of damage may also include, for example, the shape of the damaged portion, and the extended cut length L1 may be set according to the shape of the damaged portion.

The above describes a glass plate manufacturing apparatus and manufacturing method according to an embodiment of the present invention, but the embodiment of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention.

In the above embodiment, a case has been described in which a thermograph is used as the sensor 31 for measuring the object to be determined, but the sensor 31 is not limited to this. For example, the sensor 31 may be another temperature sensor such as a radiation thermometer, or a laser sensor that irradiates laser light and detects transmitted or reflected light from the object to be determined Gt, gt.

In addition, in the above embodiments, the breaking bar 25 is pressed against the glass ribbon G (scribe line formation region Gx) at a height position that is the same or approximately the same as the scribe line S. However, it may also be pressed against a portion of the glass ribbon G above the scribe line S. Here, the portion above the scribe line S refers to a portion of the glass ribbon G that is not curved in the vertical direction and is a predetermined distance above the scribe line S. This predetermined distance is 5 mm or more and less than 70 mm. Furthermore, considering that the glass ribbon G has an effective region (the region that will become the product glass sheet after breaking), this predetermined distance may be 5 mm or more and less than the distance from the scribe line S to the bottom end of the effective region. In this case, the predetermined distance is 5 mm or more and less than 20 mm, taking into account the effective region of the glass ribbon G in this embodiment.

In the above embodiment, the support means 4 rotates along a circular orbit centered on the position of the splitting bar 25 (the position shown by the solid line in Figure 1), but it may also rotate along a curved orbit other than a circular orbit. Furthermore, the operation of the support means 4 may be an operation other than a rotational operation as long as it is an operation that can curve the scribe line formation area Gx.

In the above embodiment, the support means 4 is configured to clamp and support the glass ribbon G using the chuck 27, but the support mode of the support means 4 is not limited to this. For example, the support means 4 may be configured to support the first or second main surface of the glass ribbon G by suction using a suction pad or the like.

In the above embodiment, the glass ribbon G is cut by bending along the scribe line S, but the glass ribbon G may also be cut by other methods such as laser cutting or laser melting.

1 Processing device 2 Cutting device 3 Determination device 4 Support means 11 Forming zone 12 Heat treatment zone 13 Cooling zone 14 Conveying device 15 Formed body 21 Scribe device 22 Breaking device 23 Wheel cutter 24 Support rod 25 Breaking bar 26 Support means 27 Chuck 31 Sensor 32 Determination unit 33 Control units D1 to D8 Broken G Glass ribbon g Glass sheet Gt Determination object (lower end of glass ribbon)
gt: Object to be judged (top end of glass plate)
Gx Scribe line formation area gx Standard glass plate gy Extended glass plate L0 Standard cutting length L1 Extended cutting length S Scribe line Sx Scribe line formation area

Claims (13)

A method for manufacturing a glass sheet, comprising a cutting step of cutting a glass ribbon moving downward in a vertical position along its width direction to a standard cutting length to obtain a glass sheet,
A determination step of determining whether or not a portion including at least one of a lower end of the glass ribbon and an upper end of the glass sheet after cutting in the cutting step is broken as a determination object,
a cutting step for cutting the glass ribbon to an extended cutting length longer than the standard cutting length in the next cutting step when it is determined in the determination step that there is breakage of the object to be determined. A method for manufacturing a glass plate as described in claim 1, wherein the determination process involves measuring the object to be determined using a sensor and determining whether or not the object is damaged based on the measurement results. A method for manufacturing a glass plate as described in claim 2, wherein the sensor measures the widthwise end of the object to be judged. A method for manufacturing a glass plate as described in claim 2 or 3, wherein the sensor measures the widthwise ends and widthwise center of the object to be judged. A method for manufacturing a glass plate according to any one of claims 1 to 4, wherein the value obtained by subtracting the standard cutting length from the extended cutting length is 0.05 m or more and 4.0 m or less. A method for manufacturing a glass plate described in any one of claims 1 to 4, wherein the extended cutting length is 1.02 to 4.1 times the standard cutting length. A method for manufacturing a glass plate described in any one of claims 1 to 6, wherein in the cutting process, the length of the extended cutting length is adjusted depending on the type of breakage to be determined. A method for manufacturing a glass plate as described in claim 7, wherein, in the cutting process, the length of the extended cutting length is adjusted depending on at least one of the location and size of the breakage to be determined. the cutting step includes a scribing step of forming a scribe line in the glass ribbon along its width direction, and a bending and breaking step of bending and breaking the glass ribbon along the scribe line in a state in which the glass ribbon is supported by a support means below the scribe line, to cut out the glass sheet,
The method for manufacturing a glass plate according to any one of claims 1 to 8, wherein in the bending and breaking step, a bending bar is pressed against a region of the glass ribbon where the scribe line is to be formed. the bending and breaking step is a step of bending and breaking the glass ribbon by operating the support means in a state in which the bending and breaking bar is pressed against the scribe line formation region, and bending the scribe line formation region in a vertical direction with the bending and breaking bar as a fulcrum,
10. The method for manufacturing a glass plate according to claim 9, wherein, when cutting the glass ribbon to the extended cutting length, the operating speed of the supporting means for curving the region where the scribe line is formed is slower than when cutting the glass ribbon to the standard cutting length. the bending and breaking step is a step of bending and breaking the glass ribbon by pressing the bending and breaking bar against the scribe line formation region in a state in which the support means is operated to bend the scribe line formation region in a vertical direction,
10. The method for manufacturing a glass plate according to claim 9, wherein, when cutting the glass ribbon at the extended cutting length, at least one of the operating speed of the support means that curves the scribe line formation region and the operating speed of the breaking bar that is pressed against the scribe line formation region is made slower than when cutting the glass ribbon at the standard cutting length. A method for manufacturing a glass sheet according to any one of claims 9 to 11, wherein in the cutting process, the extended cutting length is set so that, if there is any break in the glass ribbon, the broken portion is positioned below the contact position of the support means with the glass ribbon. A glass sheet manufacturing apparatus including a cutting device for cutting a glass ribbon moving downward in a vertical position along its width direction to a standard cutting length to obtain a glass sheet,
a determination unit that determines whether or not a portion including at least one of a lower end of the glass ribbon and an upper end of the glass sheet after cutting by the cutting device is broken;
a control unit that adjusts the cutting length of the glass ribbon based on the determination result of the determination unit,
The control unit sets the next cutting length of the glass ribbon by the cutting device to an extended cutting length that is longer than the standard cutting length when the determination unit determines that the object to be determined has been damaged.