TW201410621A - Thin sheet glass manufacturing method - Google Patents

Abstract

Provided is a thin sheet glass manufacturing method that has: a melting step for melting a glass raw material into a molten glass; a forming step for forming the molten glass into a glass ribbon; a transfer step for transferring the glass ribbon using transfer rollers; and a width-direction cutting step for cutting the glass ribbon in the width direction. When starting manufacture, at least a transfer-direction leading end portion of the glass ribbon is formed, in the forming step, with a thickness with which the glass ribbon can pass on the transfer rollers in the transfer step, and after the transfer-direction leading end portion of the glass ribbon is subjected to the width-direction cutting step, the thickness of the glass ribbon formed in the forming step is changed to a product thickness.

Description

Method for manufacturing thin plate glass

The present invention relates to a method of manufacturing a thin plate glass.

As a method of producing the sheet glass, there is known a method in which a molten glass is formed into a plate-shaped glass ribbon by a conveyance roller, and is conveyed and cooled in a quenching furnace, and then continuously conveyed from the quenching furnace by a cutting device. The strip-shaped glass ribbon is cut into a rectangular glass plate of a specific size (for example, Patent Document 1).

In the manufacturing process of the sheet glass, the method of conveying the glass ribbon by the conveyance roller in the inside of a cold furnace and a cutting apparatus is used.

This is usually heated from the upper surface of the glass ribbon in the cold furnace. Therefore, since the heat transfer path for the glass ribbon is ensured, there is a case where the gas is supplied while being cooled, so that the viewpoint of the supply path of the gas is ensured. Instead, use a transfer roller that can be arranged at intervals.

In the cutting device, if the glass fragments, cutting chips, and the like which are generated during the cutting are left on the transport path, the surface of the subsequent glass ribbon is scratched. Therefore, the transport roller is used to transport the glass. Fragments of glass on the path are easy to remove.

Further, in any step, the influence of the conveying roller on the quality of the glass is small, and it can be handled without depending on the thickness of the plate and the composition of the glass, and thus it is widely used.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: International Publication No. 2010/007953

However, in recent years, particularly in display applications, a thinner plate glass has been required. In other words, in the case where it is easy to produce a sheet glass having a small thickness, the above-described reason is also used when a glass ribbon is conveyed in a cold furnace or a cutting device.

However, at the beginning of the manufacture shown in Fig. 1, for example, when the front end portion of the glass ribbon 11 is made to be the target product sheet thickness, when the material flows on the transport path, the front end portion 11a of the glass ribbon 11 is deflected, resulting in When the glass ribbon cannot pass on the conveying roller 12, the like.

As a result, when the front end of the glass ribbon fails to reach the end of the manufacturing step, the thin glass cannot be produced. Therefore, it is not possible to stably produce a plate glass having a thickness that is unlikely to pass through the conveying roller, and in particular, it is a problem in that a thin plate glass having a small thickness is easily produced.

In order to allow the front end of the glass ribbon to pass through the conveying roller reliably, it is effective to reduce the roller pitch. Therefore, it is also considered to adjust the interval of the conveyance rollers, etc., but the interval 13 between the conveyance rollers 12 must be arranged such that at least the adjacent conveyance rollers do not contact each other. Therefore, the diameter of the conveying roller 12 is restricted, so that the distance is limited. In addition, the roll pitch means the distance between the centers of the adjacent rolls, that is, the sum of the diameter of the conveyance roller 12 and the interval 13 of the conveyance rolls 12 in FIG.

Further, the conveying roller 12 must have a diameter that is not deflected by itself, and the diameter is restricted by the width of the glass ribbon (the length of the glass ribbon in the vertical direction with respect to the conveying direction).

Therefore, the adjustment of the interval between the conveyance rollers and the like cannot sufficiently shorten the roller pitch, and the problem that the glass ribbon cannot pass through the conveyance roller cannot be solved. Therefore, a solution to this problem is required.

In view of the problems of the prior art described above, it is an object of the present invention to provide a At the beginning of the manufacture of the thin-plate glass, the leading end portion of the glass ribbon in the conveying direction can pass the conveying roller more reliably, thereby realizing a method for producing a thin sheet glass with improved yield and productivity.

The present invention for solving the above problems provides a method for producing a thin plate glass, comprising: a melting step of melting a glass raw material to obtain a molten glass; and a forming step of forming a molten glass to form a glass ribbon; and conveying a step of conveying the glass ribbon by a conveyance roller; and a width direction cutting step of cutting the glass ribbon in the width direction; and at the start of the production, at least the front end portion of the glass ribbon in the conveying direction is formed in the molding step The thickness of the glass ribbon that can be passed through the transporting step is changed to a thickness of the transporting roller in the transporting step, and the thickness of the glass ribbon formed in the forming step is changed to a product after the width direction cutting step is performed in the transporting direction of the glass ribbon. The thickness.

According to the method for producing a thin plate glass of the present invention, at the start of the manufacture of the thin plate glass (when the manufacturing apparatus is started), the glass ribbon can pass through the conveying roller more surely. Therefore, the yield of the thin plate glass can be improved and the productivity can be improved.

11‧‧‧glass ribbon

11a‧‧‧ front end

12‧‧‧Transport roller

13‧‧‧ interval

21‧‧‧Fusing furnace

22, 42‧‧‧ molten glass

23‧‧‧Floating kiln

24‧‧‧Fused tin

25, 43, 51, 82‧‧ ‧ glass ribbon

26, 44, 81‧‧‧Transport roller

27‧‧‧Xu cold furnace

28‧‧‧Width direction cutting device

41‧‧‧fused tube

46‧‧‧Width direction cutting device

47‧‧‧Glass belt horizontal transport part

52‧‧‧ board thickness

53‧‧‧ Thickness

71‧‧‧End

72‧‧‧Central Department

83‧‧‧ Both ends cutting device

84‧‧‧Width direction cutting device

85‧‧‧ conveyor belt

611, 621‧‧‧ Central Department

612, 622‧‧‧ end

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an explanatory view showing the behavior of a glass ribbon on a conveying roller in the prior art.

Fig. 2 is a schematic view showing a manufacturing step in a case where a floating method is used as a molding step in the embodiment of the present invention.

Fig. 3 is an explanatory view showing the thickness control in the floating method in the embodiment of the present invention.

Fig. 4 is a schematic view showing a manufacturing step in a case where a melting method is used as a molding step in the embodiment of the present invention.

Fig. 5 (a) and (b) are explanatory views showing the behavior of the glass ribbon on the conveying roller in the embodiment of the present invention.

6(a) and 6(b) are explanatory views showing the thickness distribution of the glass ribbon in the width direction in the molding method in the embodiment of the present invention.

Fig. 7 (a) and (b) are explanatory views of a cutting step in the embodiment of the present invention.

8(a) and 8(b) are explanatory views showing a cutting step in the embodiment of the present invention.

In the following, the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments described below, and various modifications and substitutions may be made to the embodiments described below without departing from the scope of the invention.

Hereinafter, a method of producing the thin plate glass of the present embodiment will be described.

According to one aspect of the present invention, a method for producing a thin plate glass according to the present invention includes: a melting step of melting a glass raw material to form a molten glass; a forming step of forming a molten glass to form a glass ribbon; and a transporting step of borrowing The glass ribbon is conveyed by a conveyance roller; and the width direction cutting step is performed to cut the glass ribbon in the width direction (the direction perpendicular to the conveyance direction of the glass ribbon).

Further, at the start of the production, in the forming step, the thickness of the front end portion of the glass ribbon in at least the conveying direction is made to pass through the thickness of the conveying roller in the conveying step, and the front end portion in the conveying direction of the glass ribbon is passed through After the width direction cutting step, the thickness of the glass ribbon formed in the forming step is changed to the thickness of the product.

First, each step will be described below.

The melting step is a step of melting the glass raw material to form a molten glass.

The glass raw material used herein is not particularly limited, and the glass raw material can be used in a specific ratio and used to be a target composition (glass type) corresponding to the performance required for the product.

Further, the temperature at which melting is performed may be selected based on the glass raw material used and its composition.

Here, there is no particular type of glass to which the manufacturing method of the present embodiment is applied. It can be used for the manufacture of, for example, soda lime glass or alkali-free glass. Since the use of the display particularly requires thin sheet glass having a thin thickness, it can be preferably used for the production of alkali-free glass.

Further, it is preferred that the molten glass obtained in the melting step is subjected to a defoaming treatment (clarification treatment) before being supplied to the forming step.

The defoaming treatment refers to a step of removing bubbles contained in the molten glass, and by performing this step, the bubbles contained in the thin glass of the final product can be reduced. Therefore, in the use of bubbles in glass such as display applications, it is preferred to carry out the treatment.

The method of the defoaming treatment is not particularly limited, and examples thereof include a method in which a clarifying agent is added to the molten glass, a method in which the molten glass is kept at a high temperature for defoaming, or a molten glass in a reduced pressure atmosphere. The method of defoaming is performed.

Next, the forming step will be described.

The forming step is a step of forming the molten glass to form a glass ribbon, and the specific method is not limited, and may be selected in accordance with the specifications required for the sheet glass of the final product. In particular, in the floating method and the melting method, since a glass ribbon (plate glass) having a high flatness can be obtained, it is preferred to carry out the forming step by any method. In addition, you can also choose the pull-down method (re-drag method or flow-down method).

Among them, the floating method can stably produce a glass ribbon having a wide width, which can improve productivity, and thus can be more preferably used as a forming method in a forming step.

The specification of the glass ribbon formed in the forming step can be selected in consideration of the specifications or productivity of the manufactured sheet glass. However, if the width of the glass ribbon is wide, the productivity is particularly improved. Therefore, the width of the glass ribbon used as the product is preferably 1.5 m or more, and more preferably 2.5 m or more. Here, the glass ribbon for a product is a glass ribbon which changes the thickness of a glass ribbon to the thickness of a product as follows. The upper limit of the width of the glass ribbon is not particularly limited and may be selected in conjunction with the upper limit of the manufacturing equipment.

Furthermore, the width of the glass ribbon at the start of manufacture is also preferably the same or the same as the width of the glass ribbon for the product, so the width of the glass ribbon at the beginning of the manufacture, It is also preferably 1.5 m or more, more preferably 2.5 m or more.

The thickness of the glass ribbon is not limited. However, the method for producing a thin glass according to the present embodiment is intended to prevent the end of the glass ribbon from being deflected by the conveyance roller when the glass ribbon is conveyed by the conveyance roller at the start of manufacture. The phenomenon of passing the roller.

In particular, when the thickness of the target product portion is thin, the conveyance roller cannot be passed when the thickness is formed at the start of the production, and the manufacturing method of the embodiment can be reliably carried out by the conveyance roller. effect. Therefore, it is preferable that the thickness of the product of the glass ribbon formed in the forming step in the thickness of the glass ribbon and the thickness of the central portion in the width direction of the glass ribbon are 0.2 mm or less. In particular, it is more preferably 0.15 mm or less, and particularly preferably 0.1 mm or less.

The thickness of the product portion referred to herein is the portion of the product after the thickness of the glass ribbon is changed to the thickness of the product after the cutting step in the width direction of the glass ribbon in the direction of the width direction (final product) The thickness of the glass ribbon is cut in the center of the width direction. The lower limit of the thickness of the central portion (product portion) in the width direction of the glass ribbon is not particularly limited. However, it is preferable to select the molding step to the width direction cutting step depending on the conveying speed, the type and characteristics of the glass, and the like. The tape does not break during transport. For example, the lower limit of the thickness of the central portion in the width direction of the glass ribbon is a stable production condition according to the principle of glass forming, and is preferably 0.01 mm or more, more preferably 0.02 mm or more, and particularly preferably 0.03 mm or more.

The transporting step is a step of transporting the formed glass ribbon in the forming step by the transport roller, and includes transporting in the cold cooling step, the width direction cutting step, and, if appropriate, the both end portion cutting steps. Since the conveying step includes the cold cooling step, the glass ribbon can be cooled and cooled during the period before the conveyance to the width direction cutting step (width direction cutting device). Therefore, in the transfer step, in order to cool the glass ribbon and cool it to a specific temperature, a quench furnace or the like may be provided to control the peripheral temperature and the like.

There is no special difference in the diameter, length, and roll spacing of the transfer rolls used in the transfer step. limited. The diameter and length of the conveying roller can be determined by the thickness and width of the manufactured sheet glass, that is, the size of the glass ribbon. Further, the roll pitch can be determined by the diameter of the transfer roller or the like.

The number of the transport rollers can be selected depending on the length of the transport step, the time required for the transport step, and the like, and is not limited.

However, in the production of the thin plate glass, as described above, the wider width of the glass ribbon can improve the productivity, and therefore, it is preferable that the length of the conveying roller is also the length in combination with this. In addition, when the length of the conveyance roller is long, the diameter (thickness) conforming to the above-described case so that the conveyance roller itself does not cause deflection, and the conveyance rollers are at least not in contact with each other. Select its roll spacing.

In the present embodiment, as described below, even if the roll pitch is increased, the possibility that the end portion of the glass ribbon cannot pass the conveyance roller at the start of the production can be suppressed, and therefore, the roll pitch can be made wide. Specifically, for example, the roll pitch between the transfer rolls is preferably 200 mm or more, more preferably 300 mm or more, and still more preferably 400 mm or more. In this case, the upper limit is not limited, and it can be selected according to the diameter of the conveying roller or the like. In the case where the quenching furnace is installed in the conveying step or the gas is circulated, the heat is easily transmitted by increasing the pitch of the rolls, and it is preferable because it is easily diffused if it is a gas.

In addition, as described above, the roller pitch means the distance between the centers of the adjacent conveying rollers, and therefore the sum of the diameter of the conveying roller and the interval between the conveying rollers. For example, referring to Fig. 1, the interval R of the transport roller and the interval 13 between the transport rollers are the roll pitch L.

The width direction cutting step is a step of cutting the glass ribbon in the width direction (the direction perpendicular to the conveyance direction of the glass ribbon) by the conveyance roller of the conveyance step.

The width direction cutting step may be performed by cutting the glass ribbon in the width direction, and is not limited to the case where the glass ribbon is accurately cut into a desired size by a specific width direction cutting device for the product. .

For example, the following case is also included in the width direction cutting step here: in order to discard the front end portion of the glass ribbon at the start of manufacture, the end of the downstream side of the conveying roller The portion (the width direction cutting device that is not connected to the product cutting) is loosened, and the glass ribbon protruding from the end portion of the conveying roller is cut (broken) in the width direction due to its own weight.

In the case where the glass ribbon is cut in the width direction for the purpose of the product, the cutting method (means) is not particularly limited, and can be selected based on the shape of the cut surface required, the cutting accuracy, and the like.

The form of the thin plate glass cut in the width direction cutting step is not limited, and may be, for example, a glass plate cut into a specific sheet size in the width direction, or a glass roll in which a thin plate glass is wound by a specific amount.

In the above, each step will be described, and a configuration example of a manufacturing apparatus of a thin plate glass which can be used in the method for producing a thin plate glass according to the present embodiment will be described with reference to Figs. 2 to 4 .

Fig. 2 is a schematic view showing a manufacturing apparatus of a thin plate glass in a case where a floating method is used in the forming step.

In the apparatus for manufacturing a thin plate glass of Fig. 2, first, a glass raw material is introduced into the melting furnace 21 to obtain a molten glass 22. Then, molten glass is supplied to the molten tin 24 in the floating kiln 23, and the molten glass is formed into the glass ribbon 25. The formed glass ribbon 25 is cooled and cooled by being held and conveyed by the conveyance roller 26. At this time, the quenching furnace 27 may be provided around the conveying roller 26 in order to cool and cool the glass ribbon at an appropriate cooling rate. Then, the cold-cooled, cooled glass ribbon can be cut to a desired size by the width direction cutting device 28.

A method of adjusting the thickness of the glass ribbon in the floating method will be described with reference to Fig. 3 . Fig. 3 is a view showing a cut surface in the line A-A' of the float kiln of Fig. 2.

As shown in Fig. 3, in the float bath, molten glass is supplied to the molten tin 24 from the left side in the drawing, and is formed into a glass ribbon during the transfer to the right side in the drawing on the molten tin 24.

The glass ribbon can be pressed from above by a rotating roller (upper roller) called an auxiliary roller, and the shrinkage of the width of the glass ribbon can be suppressed, thereby selecting and adjusting the thickness of the central portion and the glass ribbon. width. In the floating method, the end portion of the glass ribbon is pressed by the rotating roller to perform the forming step. Therefore, as shown in FIG. 6(a) below, the thickness distribution is generated in the cross section in the width direction.

Next, an outline of the configuration of the apparatus for manufacturing a thin plate glass in the case where the melting method is used in the forming step will be described with reference to Fig. 4 .

Although the description of the melting step is omitted in FIG. 4, it can be configured in the same manner as in the case of the floating method.

Then, the molten glass obtained in the melting step is supplied to a groove (not shown) provided on the upper surface of the molten pipe 41 of Fig. 4, and the molten glass 42 overflows is integrated at the lower portion of the molten pipe, thereby serving as a piece of glass ribbon 43. Formed continuously. At this time, in the lower portion of the molten tube, the glass ribbon is formed while supporting the both end portions thereof so as not to shrink in the width direction thereof, so that the sheet thickness is formed in the width direction cross section as shown in Fig. 6 (b) below. distributed.

Thereafter, the glass ribbon 43 on the conveying roller 44 is cooled and cooled by conveyance. At this time, similarly to the case of the floating method, for example, a quenching furnace may be provided around the conveying roller as indicated by a broken line in the drawing, and the temperature of the quenching step may be controlled.

A width direction cutting device 46 is provided downstream of the conveying roller 44 in the conveying direction. Thereby, it can be cut into a desired size.

Further, in Fig. 4, the thin plate glass is wound into a roll shape to form a glass roll. However, in addition to this form, the glass plate may be formed by cutting into a plate shape of a specific size as described above.

In Fig. 4, the arrangement of the conveying roller includes the portion 47 for conveying the glass ribbon in the horizontal direction. However, in the apparatus (manufacturing method) for the thin-plate glass of the melting method, the conveying path is also included in the conveying path. Horizontal part.

In this case, when the glass ribbon is conveyed by the conveyance roller at the start of manufacture, it is intended to suppress the deflection of the front end portion of the glass ribbon due to its own weight, and the phenomenon that the conveyance roller cannot be passed is likely to occur at the level of the conveyance roller. The part that is aligned in the direction. Therefore, if the conveying step of conveying the glass ribbon by the conveying roller in the horizontal direction is provided, the present invention can be further improved. The effect of the invention is therefore preferred.

Further, in the method for producing a thin plate glass according to the present embodiment, at the start of the production, the thickness of the front end portion of the glass ribbon in at least the conveying direction is set to a thickness that can be passed through the conveying roller in the conveying step. Further, after the width direction cutting step is performed at the front end portion of the glass ribbon in the conveying direction, the thickness of the glass ribbon formed in the forming step is changed to the thickness of the product.

The thickness of the front end portion in the conveying direction of the glass ribbon at the start of manufacture will be described with reference to Fig. 5 . FIGS. 5(a) and 5(b) are diagrams showing a configuration example of a cross-sectional view of the front end portion of the glass ribbon 51 in the conveyance direction at the start of manufacture and a subsequent portion of the glass ribbon 51 being conveyed on the conveyance roller.

In Fig. 5(a), the thickness 52 of the glass ribbon including the front end portion of the glass ribbon is formed into a thickness that can be passed through the transporting step in the forming step, thereby becoming thicker than the usual product. thickness.

Therefore, the glass ribbon shown in Fig. 5(a) is less flexible than the case where the thickness of the glass ribbon for the article is initially formed as shown in Fig. 1, so that the front end portion of the glass ribbon can pass through the conveying roller.

In this case, as a method of specifying (selecting) the thickness 52 of the front end portion of the glass ribbon, the following method can be mentioned.

First, the roller specifications such as the roll pitch can be determined according to the width of the glass ribbon to be produced and the specifications of the manufacturing equipment of the thin glass, and the allowable deflection amount of the manufacturing equipment can be calculated.

On the other hand, it can be estimated by numerical simulation or the like according to the thickness of the glass ribbon to be produced, the cross-sectional shape of the sheet width and the width direction (= plate thickness distribution), and the elastic modulus and specific gravity of the glass. The amount of static deflection of the cantilever beam. Further, the maximum dynamic deflection amount can be estimated in consideration of vibration or the like of the conveying device or the like.

Then, the allowable amount of deflection is compared with the value obtained by multiplying the safety factor by the maximum dynamic deflection amount. If the allowable deflection amount is large, it can be judged that the glass ribbon having the thickness can be stably conveyed.

In other words, the allowable deflection amount calculated from the manufacturing equipment can be made larger than the thickness of the product of the maximum dynamic deflection amount and the safety factor calculated from the glass ribbon (shape, material, etc.) to be produced, so that the glass ribbon can be conveyed. The thickness 22 of the front end portion passes through the thickness of the conveying roller in the conveying step.

Further, although an example in which the glass ribbon is uniformly thickened is shown in Fig. 5(a), the front end portion of the glass ribbon at least in the conveyance direction may pass through the thickness of the conveyance roller. Therefore, for example, as shown in FIG. 5(b), the range near the front end portion can be set to the thickness 53 of the conveyance roller, and the thickness 53 of the case can be selected based on the same calculation as described above.

However, when the thickness of the glass ribbon is changed, if the glass ribbon is changed violently, the glass ribbon may be broken. Therefore, as shown in FIG. 5(a), the thickness is thickened over the fixed range, and thereafter Slowly change the thickness of the plate.

Moreover, there is a case where the glass ribbon has a plate thickness distribution in the width direction as described above. A specific example is shown in Fig. 6. Fig. 6(a) shows the cross-sectional shape in the width direction (direction perpendicular to the conveying direction) of the glass ribbon in the case where the floating method is used in the forming step, and Fig. 6(b) shows the case where the melting method is used in the forming step. The cross-sectional shape of the glass ribbon in the width direction (the direction perpendicular to the transport direction).

In the case of forming by a floating method or a melting method, as shown in Fig. 6, generally, the central portions 611, 621 of the glass ribbon are part of the product, and the both end portions 612, 622 are thicker than the central portion. . This is because, in order to make the central portion of the glass ribbon a specific thickness, the both ends of the glass ribbon are stretched by a roll or the like in the forming step, or the molding is maintained.

Further, when the maximum dynamic deflection amount is calculated as described above, the cross-sectional shape (plate thickness distribution) in the width direction of the glass ribbon is used as a calculation element. Therefore, when the entire thickness of the glass ribbon is controlled so that the sheet can pass over the conveyance roller, the thickness of at least the front end portion of the glass ribbon (for each portion in the width direction) is set to a specific value.

Then, the width direction cutting step is performed at the front end portion of the glass ribbon in the conveying direction Thereafter, the thickness of the glass ribbon formed in the above molding step is changed to the thickness of the product.

After the cutting step in the width direction of the leading end portion in the conveying direction of the glass ribbon, a continuous glass ribbon is formed from the forming step to the cutting step in the width direction. That is, the upstream side is cut off in the width direction, and the front end of the glass ribbon is not present.

Since the front end portion of the glass ribbon that does not pass the conveyance roller does not exist on the upstream side in the width direction cutting step as described above, the sheet thickness of the glass ribbon is changed to a sheet for the product which is thinner than the start of manufacture. It is thick and can pass through the conveying roller stably.

Here, the term "change the thickness of the glass ribbon to the thickness of the product" means a portion of the product portion 611, 621 of the central portion when the glass ribbon has a thickness distribution in the width direction as shown in FIG. It is formed in such a manner as to become a plate thickness for the product (the target thickness).

The method of changing the thickness of the glass ribbon to the thickness of the product is preferably carried out by a method selected from one or more of the following methods. In other words, it may be carried out by only one method selected from the following methods, or two or more types may be combined.

A method of increasing the transport speed of the above-mentioned glass ribbon in the forming step.

A method of reducing the supply amount (per unit time) of the molten glass to the forming step (slowing the supply speed).

A method of increasing the width of a glass ribbon.

A method of changing the thickness distribution in the width direction of the glass ribbon.

According to any of the above methods, the thickness of the product portion of the glass ribbon can be easily changed, which is preferable.

Further, the thickness of the glass ribbon to be used for the product may be performed immediately after the width direction cutting step at the front end portion of the glass ribbon in the conveying direction as described above, but may be performed after a fixed period of time. However, in any case, if the thickness of the glass ribbon in the forming step is changed abruptly, the glass ribbon may be broken during the transport step, and therefore it is preferably (for example, from 1 hour to 1 day). Slowly thin the thickness of the glass ribbon and eventually The thickness of the finished product.

Further, in the case of producing a plurality of sheets of glass having a predetermined thickness, from the viewpoint of productivity, it is preferable to produce a thicker plate in the order of thickness by making the thickness of the glass ribbon thinner. The product is finally combined (changed) into the thinnest product of the thickness of the sheet to produce the thickness of the glass ribbon. That is, for example, it is also possible to initially produce a glass having a relatively thick plate thickness (for example, 0.7 mm or more), and then to produce a glass having a thin plate thickness (for example, 0.3 mm), and thereafter to produce the thinnest batch of the plate. Glass (for example, 0.2 mm or less).

Further, in the method for producing a thin plate glass described in the present embodiment, not only the width direction cutting step but also the both end portion cutting steps of cutting both end portions (ear portions) in the width direction of the glass ribbon may be provided. This aspect will be described below.

As described above, the glass ribbon as the object to be cut is molded by, for example, a floating method or a melting method, but is cooled during the conveyance step. Further, the glass ribbon formed by the floating method or the melting method may have a portion having a thickness different from that of the central portion at both end portions in the width direction as described below. Therefore, both ends of the product in the width direction are also cut. This aspect will be described using FIG. 7.

Fig. 7(a) is a view showing the glass ribbon from the upper surface, and Fig. 7(b) is a cross-sectional view showing the width direction of the glass ribbon obtained by observing the glass ribbon in the direction of the arrow A in Fig. 7(a).

Fig. 7(b) is a cross-sectional view in the width direction of the glass ribbon in the case of being formed by the melting method as described above, but in this case, the direction of conveyance with the glass ribbon (the arrow in Fig. 7(a) The direction shown in the vertical direction is such that the both end portions 71 are thicker than the central portion 72 of the product.

In the case where the glass ribbon has the shape, not only the width direction of the broken line Y shown in FIG. 7(a) for forming the thin plate glass of the desired length but also the both ends (the ear portion) can be removed. 71 can also be cut in the broken line X shown in Fig. 7(a).

Both the broken line X and the broken line Y may be cut first, but it is preferable to cut the broken line Y after cutting the broken line X.

In other words, it is preferable to have a both-end portion cutting step of cutting both end portions in the width direction of the glass ribbon before the cutting step in the width direction.

The both end portion cutting step and the width direction cutting step will be described with reference to Fig. 8 .

Fig. 8(a) is a view schematically showing a configuration in which the glass ribbon is cut in the above-described order as viewed from the upper surface side, and Fig. 8(b) is a schematic view showing the side surface as viewed from the arrow B in Fig. 8(a). .

In the both end portion cutting step and the width direction cutting step, the glass piece or the like generated at the time of cutting is conveyed to the width direction cutting device 84 so as not to remain on the conveying path by the plurality of conveying rollers 81.

Further, before the widthwise cutting device 84, a continuous glass ribbon 82 is formed from the forming step.

The glass ribbon 82 continuously conveyed by the transport roller 81 as shown in FIG. 8 is first cut at both end portions in the width direction. Therefore, the cutting line shown by the broken line X in the figure is cut by both ends. The cutting device 83 performs cutting.

Then, the glass ribbon is conveyed by the conveyance roller 81, and is cut by the width direction cutting device 84 to become the length of the desired thin plate glass, and conveyed to the unillustrated by the conveyance belt 85. Show the place where the product is placed, etc.

In this case, before the both end portions of the glass ribbon are cut by the both end portion cutting devices 83, since the thickness of the both end portions is thick as described above, as shown in Fig. 8(b), the glass ribbon is used. Maximum thickness, with a thickness of T1.

However, the maximum thickness of the glass ribbon after passing through the both end portion cutting devices 83 becomes T2 which is thinner than T1. The reason for this is that, as explained in FIG. 7(b), the glass ribbon which has passed through the both end portion cutting devices is only a product portion (center portion) 72 having a small thickness.

Therefore, in the glass ribbon, the portion which passes through the both end portion cutting devices is particularly likely to be deflected due to the thin thickness. Therefore, when the product portion at the tip end portion of the glass ribbon in the conveying direction is initially formed at the beginning of the production, it is more difficult to pass the both end portions. The conveying roller between the cutting device and the width direction cutting device.

On the other hand, in the method for producing a thin plate glass according to the present embodiment, the thickness of the end portion in the direction in which the glass ribbon is conveyed is thicker at the start of manufacture, and after passing through the width direction cutting device at the tip end portion thereof (through the width direction) After the cutting step), the thickness of the glass ribbon is changed. Therefore, the front end portion of the glass ribbon can more surely reach the portion of the cutting device in the width direction.

The specific cutting method in the width direction cutting step and the both end portion cutting steps described herein is not limited, and can be performed, for example, by cutting or by using laser light to be blown. Further, it is also possible to use a different cutting method in the width direction cutting step and the both end portion cutting steps.

In the case of cutting by cutting, in general, the cutting is performed by the following two-stage steps: a scribing step, which is creased (dash); and a cutting step, which is a scribing step The line formed in the middle is the starting point, and the glass ribbon is actually disconnected (cut).

Further, as described above, the width direction cutting step is performed after the both end portion cutting step, and the both end portions (ear portions) of the glass ribbon are actually actually used (for example, when two cutting steps are performed by cutting) After the breaking step of the disconnection, the cutting step of actually breaking in the width direction may be performed, and the order of the scribing steps of the respective portions is not limited.

That is, for example, it may be a method of performing the step of scribing the both end portions of the glass ribbon and the step of marking the width direction (the order of the scribing step is not limited), and then sequentially performing the strip ends The cutting step of breaking the part and the cutting step of breaking in the width direction.

Further, the cutting step and the cutting step may be sequentially performed for each cutting step. That is, after the step of scribing the both end portions of the glass ribbon and the cutting step of breaking the both end portions of the glass ribbon, the step of marking the width direction of the glass ribbon and the width along the glass ribbon may be sequentially performed. The direction of the disconnection step.

In the method for producing a thin plate glass according to the present embodiment, when the both end portion cutting step and the width direction cutting step are applied in the order described herein, it is preferable that the forming step is performed. The thickness of the product of the formed glass ribbon and the thickness of the central portion (product portion) in the width direction of the glass ribbon are 0.3 mm or less.

The reason for this is that when the glass ribbon having the thickness in the central portion (product portion) in the width direction of the tip end portion in the conveyance direction is supplied at the start of the production, it is particularly difficult to pass the end portion cutting device. Although it is a conveyance roller, according to the method demonstrated by this embodiment, it can pass a conveyance roller more reliably, and it is especially effective.

Further, the thickness of the central portion in the width direction of the glass ribbon is preferably 0.2 mm or less, more preferably 0.15 mm or less, and still more preferably 0.1 mm or less.

The lower limit of the thickness of the central portion (product portion) in the width direction of the glass ribbon is not particularly limited, but it is preferable to select the molding step to the width direction cutting step depending on the conveyance speed, the type and characteristics of the glass, and the like. The thickness of the glass ribbon that does not break during transport. For example, according to the stable production conditions of the glass forming principle, the lower limit of the thickness of the central portion in the width direction of the glass ribbon is preferably 0.01 mm or more, more preferably 0.02 mm or more, and particularly preferably 0.03 mm or more.

Here, the thickness of the center portion in the width direction of the glass ribbon refers to the thickness of the glass ribbon formed in the forming step after the cutting step in the width direction of the glass ribbon is changed to the product. In the case of the thickness, for example, the thickness of the product portions (center portions) 612 and 622 in Fig. 6 is thick.

In the case where the broken line X is cut after the broken line Y shown in Fig. 7(a) is cut, that is, when the width direction cutting step is performed first and then the both end portions are cut, it is preferable. The thickness of the product of the glass ribbon formed in the above molding step and the thickness of the central portion in the width direction of the glass ribbon are 0.2 mm or less.

This is because the front end of the glass ribbon cannot pass the conveyance roller before the cutting step in the width direction when the sheet is formed to have such a thickness from the start of the production as before, and the manufacturing method of the present embodiment is In the middle, the conveyance roller can be surely passed before the cutting step in the width direction, thereby exerting the effect.

Further, as described above, after the front end portion of the glass ribbon reaches the width direction cutting step, it becomes a continuous glass ribbon from the forming step to the width direction cutting step, and the glass is not present on the upstream side in the width direction cutting step. Belt the front end. In the same manner as in the width direction cutting step, the front end portion of the glass ribbon which is the cause of the inability to pass the conveying roller is not present on the upstream side, and the thickness of the glass ribbon is changed to be smaller than the above range at the start of manufacture. The plate is thick and can also be passed through a transfer roller.

Since the glass system after the width direction cutting step is lowered to a temperature close to room temperature, the restriction of the diameter or the pitch of the conveying roller can be reduced, and various conveying methods (small-diameter conveying rollers, belt conveyance, or Air suspension transport, etc.).

Further, the thickness of the central portion in the width direction of the glass ribbon is preferably 0.15 mm or less, and particularly preferably 0.1 mm or less.

Further, the thickness of the product portion of the glass ribbon is as described above. In addition, the lower limit of the thickness of the center portion (product portion) in the width direction of the glass ribbon is not particularly limited as described above, and the molding step to the width direction can be selected depending on the conveyance speed, the type and characteristics of the glass, and the like. The thickness of the glass ribbon that does not break during transport before the breaking step. Specifically, for example, the stable production conditions according to the glass forming principle are preferably 0.01 mm or more, more preferably 0.02 mm or more, and still more preferably 0.03 mm or more.

According to the method for producing a thin plate glass according to the present embodiment described above, at the start of production (when the manufacturing apparatus is started), the glass ribbon can pass through the conveying roller more surely, thereby achieving an improvement in yield and productivity.

Example

Specific examples and comparative examples are described below, but the present invention is not limited to the examples.

[Example 1]

In the present embodiment, the manufacture of the thin plate glass was carried out in accordance with the following procedure.

(melting step) mixing the glass raw material into an alkali-free glass and supplying it To the melting furnace, molten glass was produced.

(Molding step) The molten glass from the melting furnace is supplied to molten tin of a floating kiln to form a glass ribbon.

At this time, at the start of the production, the glass ribbon was continuously formed so that the sheet width was 4.6 m, and the thickness of the center portion (product portion) (the portion 611 in Fig. 6 (a)) was 0.3 mm. The shape of the glass ribbon is determined in advance to allow the amount of deflection of the manufacturing equipment to be greater than the product of the maximum dynamic deflection of the glass ribbon and the safety factor.

(Transfer step) The roll pitch is set to 450 mm, and the glass ribbon formed in the above-described forming step is conveyed on a transfer roller in which a plurality of rolls are disposed.

(Weight Direction Cutting Step) The glass ribbon conveyed to the cutting device by the conveying step is cut into a desired length.

(Through End Portion Cutting Step) In the width direction cutting step, the glass sheets having the desired length are cut at both end portions in the width direction.

That is, after cutting by the Y cutting line in Fig. 7 (a), the cutting is performed by the X cutting line.

Further, in the above-described manufacturing step, after the end portion of the glass ribbon was cut in the width direction, the sheet width was 4.6 m as the shape of the formed glass ribbon in the forming step, and the product portion was The plate thickness (part 611 in Fig. 6(a)) was changed to 0.1 mm. The method of changing the thickness of the product portion by changing the thickness distribution in the width direction of the glass ribbon and the method of accelerating the transport speed of the glass ribbon by using the upper roller shown in FIG. 3, and further reducing the supply amount of the molten glass Combine and proceed.

In the present embodiment, the leading end portion in the conveying direction of the glass ribbon can be cut in the width direction even at the start of manufacture. Moreover, after confirming that the thickness of the product part was changed, the glass ribbon was also conveyed on the conveyance roller without breaking.

[Comparative Example 1]

In the comparative example, in the forming step, the glass ribbon is made to be the target of the final product at the start of the production, that is, the plate width is 4.6 m, and the center portion (product portion) In the same manner as in Example 1, the production of the thin plate glass was started except that the thickness was 0.1 mm.

At this time, the shape of the glass ribbon is such that the allowable deflection amount of the manufacturing apparatus is larger than the product of the maximum dynamic deflection amount of the glass ribbon and the safety factor.

After the production of the thin plate glass was started under the conditions of the comparative example, the glass ribbon formed in the molding step could not pass through the conveyance roller of the conveyance step, and the width direction cutting step could not be obtained, so that the sheet glass of the target specification could not be produced.

[Industrial availability]

The present invention is suitable for the manufacture of sheet glass and the like.

The present application is based on Japanese Patent Application No. 2012-177513, filed on Jan.

12‧‧‧Transport roller

51‧‧‧glass ribbon

52‧‧‧ board thickness

53‧‧‧ Thickness

Claims (7)

A method for producing a thin plate glass, comprising: a melting step of melting a glass raw material to obtain molten glass; a forming step of forming a molten glass to form a glass ribbon; and a transferring step of conveying the glass by a conveying roller And a width direction cutting step of cutting the glass ribbon in the width direction; at the start of the manufacturing, the thickness of the front end portion of the glass ribbon in at least the transport direction is allowed to be transported by the transport step in the forming step The thickness of the roll is changed to the thickness of the product by the thickness of the glass ribbon formed in the forming step after the width direction cutting step at the front end portion of the glass ribbon in the conveying direction. The method for producing a thin plate glass according to claim 1, wherein the method of changing the thickness of the glass ribbon formed in the forming step to the thickness of the product is performed by one or more methods selected from the group consisting of: speeding up the forming step The conveying speed of the glass ribbon is reduced; the amount of molten glass supplied to the forming step is reduced; the width of the glass ribbon is increased; and the thickness distribution in the width direction of the glass ribbon is changed. The method for producing a thin plate glass according to claim 1 or 2, further comprising a cutting step of cutting both end portions of the glass ribbon in the width direction before the width direction cutting step. The method for producing a sheet glass according to claim 3, wherein the thickness of the product of the glass ribbon formed in the forming step and the thickness of the central portion in the width direction of the glass ribbon are 0.3 mm or less. The method for producing a sheet glass according to any one of claims 1 to 4, wherein the forming The thickness of the product of the glass ribbon formed in the step and the thickness of the central portion in the width direction of the glass ribbon are 0.2 mm or less. The method for producing a sheet glass according to any one of claims 1 to 5, wherein the width of the glass ribbon is changed to a thickness of the product, and the width of the glass ribbon is 1.5 m or more. The method for producing a sheet glass according to any one of claims 1 to 6, wherein the conveying roller has a roll pitch of 200 mm or more.