JP7095471B2 - Tubular glass cutting method - Google Patents

Description

The present invention relates to a tubular glass cutting method for forming a tube glass by cutting a tubular glass to a predetermined length.

A tubular glass cutting method for forming a tube glass by cutting (roughly cutting) continuous tubular glass to a predetermined length is well known. In this tubular glass cutting method, for example, a crack (scribing) is made in the tubular glass by a laser while constantly applying bending stress to the tubular glass, and then bending stress is applied to the tubular glass to extend and break the crack. A laser-type cutting method for obtaining a tube glass having a predetermined length is well known (see Patent Document 1 and the like).

Japanese Unexamined Patent Publication No. 2017-77991

However, in the case of the laser-type cutting method, when the tubular glass after crack formation is irradiated with a laser to be broken while applying bending stress, the start position of the crack to be extended is not stable, and the end face (folding) is formed in the tubular glass. In some cases, it was not possible to ensure good quality of the surface), and some measures were required.

An object of the present invention is to provide a tubular glass cutting method that enables good quality assurance of end faces of tubular glass.

The tubular glass cutting method for solving the above problems is a crack forming step of irradiating the tubular glass with a laser to form cracks in the tubular glass, and applying bending stress to the tubular glass in which the cracks are formed. It is a method including a folding step of extending the crack and cutting the tubular glass, and the crack forming step and the folding step are executed in separate steps that are not synchronized with each other.

According to this configuration, since the crack forming step and the folding step are not synchronized, when the tubular glass in which the crack is formed is cut in the folding step, the crack is extended from the stable crack end as a base point. It is possible to perform the process of folding. In this way, if the base point of crack extension is stable, the distance from the base point of crack extension to the end point is stable. Therefore, since the cutting of the tubular glass in the folding process is standardized, it is possible to ensure the good quality of the glass edge.

In the tubular glass cutting method, the direction of the line connecting the center of the crack in the circumferential direction and the axial center of the tubular glass is preferably different from the direction in which the bending stress is applied. According to this configuration, when the tubular glass is cut by bending stress, the bending stress is concentrated at or near the crack end, and the crack easily extends from the crack end. In this way, since the crack can be extended from a stable base point, the cutting of the tubular glass is standardized. Therefore, in this respect, it is advantageous to ensure good quality of the end face of the tubular glass.

In the tubular glass cutting method, the angle formed by the line connecting one of the crack ends of the crack and the axial center of the tubular glass with respect to the line in the weighting direction is set to -10 to +10 degrees. preferable. According to this configuration, the crack easily extends from the crack end.

In the tubular glass cutting method, it is preferable to produce a plurality of tube glasses from one tubular glass by carrying out the crack forming step and the folding step on the continuously molded tubular glass. According to this configuration, it is possible to manufacture a plurality of tube glasses having stable end face quality from one tubular glass.

In the tubular glass cutting method, it is preferable that the crack forming step and the folding step are carried out on the tubular glass continuously formed while winding the molten glass in the circumferential direction with a sleeve. According to this configuration, the direction of the line connecting the circumferential center of the crack and the axial center of the tubular glass is different from the bending stress loading direction by utilizing the fact that the tubular glass is formed while rotating by the sleeve. It becomes possible.

In the tubular glass cutting method, the pulling speed of the tubular glass from the sleeve is preferably set to 0.1 to 10 m / sec. According to this configuration, it becomes possible to efficiently cut the tubular glass.

In the tubular glass cutting method, in the folding step, it is preferable to cut the tubular glass with a jig while supporting the tubular glass with a support roller. According to this configuration, the tubular glass can be broken by a jig with the support roller as a fulcrum, so that the tubular glass can be easily cut.

The tubular glass cutting method for solving the above problems is a crack forming step of irradiating the tubular glass with a laser to form cracks in the tubular glass, and applying bending stress to the tubular glass in which the cracks are formed. It is a method including a folding step of extending the crack and cutting the tubular glass, and the folding step is executed after the secondary crack extending region is formed in the crack. According to this configuration, cracks can be extended from a more stable base point, so that good quality of the glass edge can be ensured.

The tube glass that solves the above problems includes a crack formed by irradiation with a laser, a folded surface formed by extending the crack by bending stress, and a confluence of crack extension extending from the end of the crack. Is formed on the end face in the axial direction so that the line connecting the center in the circumferential direction of the crack and the confluence point does not pass through the center of the axis.

According to the present invention, good quality of the end face of the tubular glass can be ensured.

The block diagram of the tube glass manufacturing apparatus of one Embodiment. Configuration diagram of the tubular glass cutting device. (A) and (b) are explanatory views of the crack formation process. (A) and (b) are explanatory views of the folding process. Sectional view of tube glass. Explanatory drawing which shows the directional relationship between the irradiation direction of a laser and the bending stress of cutting. Explanatory drawing which shows the angle which a crack end makes with respect to the line in the weighting direction of bending stress. Partially enlarged cross-sectional view showing a secondary crack extension region of another example.

Hereinafter, a tubular glass cutting method and an embodiment of tube glass will be described with reference to FIGS. 1 to 7.
As shown in FIG. 1, the tube glass manufacturing apparatus 1 includes a glass melting furnace 2 that melts a glass raw material to generate molten glass M, a muffle furnace 3 that draws and forms the molten glass M into a tubular shape, and a muffle furnace 3. It is provided with an annealing device 4 for annealing (heat-treating) the tubular glass G (continuous tube glass) sent from the glass, and a tube drawing device 5 for forming the tubular glass G after the annealing process. Further, the tube glass manufacturing device 1 includes a tubular glass cutting device 6 that cuts the tubular glass G towed by the tube pulling device 5, and a conveyor 7 that conveys the tube glass G'after cutting.

The muffle furnace 3 includes a sleeve 8 that rotates around the axis L1 to form the molten glass M into a tubular shape (tubular glass G). The sleeve 8 is made of, for example, a cylindrical refractory material. The sleeve 8 is partially formed in a tapered shape, and is arranged in a state where the small diameter side end portion 9 of the tapered portion faces diagonally downward. The sleeve 8 is rotated by a drive device 11 connected via a shaft 10 to wind the molten glass M supplied from the glass melting furnace 2 in a cylindrical shape and form a tubular shape from the side of the small diameter side end portion 9. Drawer molding. The molten glass M formed by drawing out into a tubular shape is continuously drawn out as the tubular glass G to the outside of the muffle furnace 3.

The annealing 4 removes the strain of the tubular glass G by a predetermined annealing treatment. The temperature of the annealing treatment, the heating time, and the like are set to various values as needed.
The tube pulling device 5 pulls the molten glass M drawn out in a tubular shape in the muffle furnace 3 and the tubular glass G passing through and passing through the annealing 4 at a constant speed to cut the tubular glass G into a tubular glass cutting device 6. To transport to. The tube pulling device 5 of this example is adjusted to a predetermined outer diameter by pulling the tube to the downstream side while sandwiching the upper part and the lower part of the tubular glass G by a pair of transport belts (not shown). The tubular glass G is conveyed to the tubular glass cutting device 6. Further, by increasing the speed of the pair of transport belts, the speed at which the molten glass M is drawn out as the tubular glass G to the outside of the muffle furnace 3 can be increased.

As shown in FIGS. 2 to 4, the tubular glass cutting device 6 forms a crack C (also referred to as a screen) in the tubular glass G by a laser LA and then applies a bending stress F to cut the tubular glass G into a predetermined length. It is cut into tubes and processed into tube glass G'. In this case, the tubular glass cutting device 6 has a crack forming portion 12 that forms a crack C in a part of the tubular glass G in the circumferential direction, and a tubular glass G by applying a bending stress F to the tubular glass G to extend the crack C. A crack extension portion 13 for breaking G is provided.

As described above, the tubular glass cutting method of this example includes a step of forming a crack C in the tubular glass G by the crack forming portion 12 (crack forming step) and a bending stress in the tubular glass G after the crack is formed by the crack extending portion 13. A step (folding step) of cutting the tubular glass G by adding F to extend the crack C is provided. Further, in the case of this example, the crack forming step and the folding step are executed in separate steps that are not synchronized with each other.

The crack forming portion 12 is a laser light irradiation device 12a that forms a crack C in the tubular glass G by the laser LA. The laser light irradiation device 12a is preferably, for example, a multiphoton absorption laser. Further, the laser light irradiating device 12a forms a crack C in a part of the tubular glass G by partially irradiating the tubular glass G with the laser LA from one direction.

The crack extending portion 13 folds the tubular glass G in contact with the holding roller 14 that holds the conveyed tubular glass G from one side, the support roller 15 that supports the tubular glass G from the other side, and the tubular glass G. A breaking jig 16 (holding roller 16a) is provided. The holding roller 14, the supporting roller 15, and the holding roller 16a are arranged side by side along the transport path L2 of the tubular glass G. The holding roller 14 and the support roller 15 adjust the positions of the tubular glass G in the transport direction, and position the tubular glass G so as to sandwich the transported tubular glass G. The pressing roller 16a is rotatably provided around the axis P at the center of the shaft portion 17 (in the direction of arrow A in FIG. 2), and protrusions 18 that come into contact with the tubular glass G are provided at both ends of the shaft portion 17. .. The pressing roller 16a rotates at a constant speed using a motor or the like as a drive source when processing the tubular glass G.

Next, the operation and effect of the tubular glass cutting device 6 will be described with reference to FIGS. 3 to 7, and the tubular glass cutting method will be described.
As shown in FIG. 3A, when the tubular glass G is conveyed to the crack formation position, the laser light irradiation device 12a irradiates the tubular glass G with the laser LA to form the crack C in the tubular glass G. (Crack forming step). The laser LA irradiates the tubular glass G at a focal length that reaches the inside of the tubular glass G.

As shown in FIG. 3B, the laser light irradiation device 12a of this example scans the laser LA from “B1” to “B2” in the circumferential direction of the tubular glass G while changing the focal length of the laser LA, for example. By doing so, a predetermined crack C is formed. Since the tubular glass G is sent out while rotating in the circumferential direction by the sleeve 8, the tubular glass G is irradiated while the focal length of the laser LA is adjusted, and cracks C are formed. In the case of this example, the crack C is formed in a straight line extending in a direction orthogonal to the line connecting the center Pr of the crack C and the axial center Pk of the tubular glass G.

Here, the thickness of the tubular glass G (tube glass G') is "w", and the outer diameter is "r". In the case of this example, the thickness w is preferably set to 0.2 to 2 mm, and the outer diameter r, which is the distance from the axis center Pk of the tubular glass G, is preferably set to 1 to 50 mm. ..

As shown in FIGS. 4A and 4B, after the crack C is formed in the tubular glass G, the tubular glass G is conveyed to the folding position, and the tubular glass G is folded (folded) to a predetermined length. Splitting process). In the case of this example, as shown in FIG. 4B, the tubular glass G is pulled out while being rotated by the sleeve 8, so that when the tubular glass G reaches the folding position, the crack C is in the circumferential direction of the tubular glass G. Moves to a position deviated by a predetermined distance. That is, when the tubular glass G reaches the folding position, the center Pr of the crack C moves by a predetermined distance in the circumferential direction as compared with the case where the crack C is formed.

When the tubular glass G is conveyed to the folding position, the pressing roller 16a rotates in the folding direction A around the axis P, so that the protrusion 18 at the tip comes into contact with the tubular glass G. At this time, a load is applied to the tubular glass G, whereby a bending stress F is applied to the tubular glass G from the protrusion 18. In the case of this example, at the time of cutting, the protrusion 18 contacts the apex of the tubular glass G (the intersection of the straight line extending in the vertical direction through the axis center Pk and the tubular glass G), and the bending stress F downward in the vertical direction is tubular. Added to glass G. Further, bending stress F is applied to the tubular glass G in a state where both sides are supported by the holding roller 14 and the supporting roller 15.

In this way, after irradiating the laser LA between the holding roller 14 and the supporting roller 15, the protrusion 18 comes into contact with the tubular glass G on the downstream side of the supporting roller 15 until the irradiation of the laser LA is completed. No bending stress F is applied to the tubular glass G. Therefore, the crack forming step and the folding step can be executed in separate steps that are not synchronized with each other.

When the bending stress F is applied to the tubular glass G, the crack C extends in both the clockwise and counterclockwise directions of FIG. 4B with the end of the crack C (crack end 19a) as a base point. Here, cracks C extend from both ends of the cracks C, and these crack extensions 20 (one is referred to as “20a” and the other is referred to as “20b”) have a portion supported by the support roller 15 as a confluence point S. , These crack extensions 20a and 20b are extended. More specifically, the crack extension 20a extending from the crack end 19a and the crack extension 20b extending from the crack end 19a through the crack end 19b extend to the confluence point S, and the tubular glass G is divided at the timing of the confluence. To. In this way, the continuous tubular glass G is cut to a predetermined length to form a tube glass G'. Therefore, the crack C, the split surface 22, and the confluence point S are present on the axial end surface 21 of the tubular glass G.

After the tubular glass G is folded, the tube glass G'is produced from the remaining tubular glass G by the same procedure. In this case as well, the crack C is first formed again in the tubular glass G and is re-transported to the folded position. Subsequently, of the two protrusions 18 of the pressing roller 16a, another protrusion 18 different from the one used for the previous folding hits the tubular glass G as the rotation around the axis P occurs, and the tubular glass G Is disconnected. Then, by repeating the above steps, a plurality of tube glasses G'are manufactured from one continuous tubular glass G.

FIG. 5 shows the shape of the end face 21 of the tube glass G'manufactured by the tubular glass cutting method of this example. The tube glass G'of this example has a crack C formed by irradiation with a laser LA, a folded surface 22 formed by extending the crack C by bending stress F, and a crack extending from each end of the crack C. It has a confluence S of extensions 20a and 20b. Further, the tube glass G'of this example is formed so that the line La connecting the center Pr in the circumferential direction of the crack C and the confluence point S does not pass through the axis center Pk of the tube glass G'(tubular glass G). ing.

In the case of the present embodiment, since the crack forming step and the folding step are not synchronized, when the tubular glass G in which the crack C is formed is cut in the folding step, the crack C is formed with the crack end 19a as a base point. It is possible to extend and fold it. In this way, if the base point of the crack extension 20 is stable, the distance from the base point of the crack extension 20 to the end point (the confluence S of the crack extensions 20a and 20b) is stable. Therefore, since the cutting of the tubular glass G in the folding step is standardized, the good quality of the end face 21 of the tubular glass G can be ensured. When the crack forming step and the folding step are synchronized, the crack C is stretched by the bending stress F at the same time as the crack C is formed by the laser LA, so that the crack C is stretched from the base point to the end point (crack stretch 20a, 20b) of the crack stretch 20. The distance to the confluence S) is not stable.

FIG. 6 shows the directional relationship between the irradiation direction of the laser LA and the bending stress F of cutting. By the way, in the case of this example, the formation of the crack C by laser irradiation and the extension of the crack C by bending are not performed at the same time, but these are made asynchronous and the tubular glass G is pulled out while being rotated by the sleeve 8. The line Lb connecting the center Pr in the circumferential direction of the crack C and the axial center Pk of the tubular glass G has a different direction with respect to the weighted direction of the bending stress F.

In this case, when the tubular glass G is cut by the bending stress F, the bending stress F is concentrated at or near the crack end 19a, and crack extension is likely to occur from the crack end 19a. In this way, the crack C can be extended from the stable base point. In this way, since the crack C can be extended from the stable base point, the cutting of the tubular glass G is standardized. Therefore, in this respect, it is advantageous to ensure good quality of the end face 21 of the tubular glass G.

Further, as shown in FIG. 7, the angle θ1 formed by the line connecting the crack end 19a and the axial center Pk of the tubular glass G with respect to the line Lc in the weighting direction of the bending stress F is set to -10 to +10 degrees. ing. The crack end 19a whose angle is to be set is the angle formed by the line Lc of the two crack ends 19a and 19b in the weighting direction of the bending stress F and the axis center Pk of the tubular glass G. The crack end with the smaller absolute value is used. In this case, the crack C is likely to extend from the crack end 19a. In order to facilitate the extension of the crack C, it is more preferable that the angle θ1 formed by the crack end 19a with respect to the line Lc in the weighting direction of the bending stress F is set to −5 to +5 degrees.

In the case of this example, a plurality of tube glasses G'are manufactured from one tubular glass G by performing a crack forming step and a folding step on the continuously formed tubular glass G. Therefore, it is possible to manufacture a plurality of tube glass G'with stable quality of the end face 21 (glass end) from one tubular glass G.

In the case of this example, the molten glass M is formed as a tubular glass G by sending the molten glass M downstream by the tube pulling device 5 while winding the molten glass M in the circumferential direction by the sleeve 8, and while winding the molten glass M in the circumferential direction. A crack forming step and a folding step are carried out on the continuously formed tubular glass G. Therefore, by utilizing the fact that the tubular glass G is formed while being rotated by the sleeve 8, the direction of the line La connecting the central Pr in the circumferential direction of the crack C and the axial center Pk of the tubular glass G and the bending stress F. The weighting direction can be different.

The pulling speed of the tubular glass G from the sleeve 8 is set to 0.1 to 10 m / sec. Therefore, the tubular glass G can be cut efficiently. The speed can be adjusted by adjusting the speed of the pair of transport belts in the pipe pulling device 5.

In the folding step, the tubular glass G is cut by the jig 16 while the tubular glass G is supported by the support roller 15. Therefore, since the tubular glass G can be folded by the jig 16 with the support roller 15 as a fulcrum, it becomes easy to cut the tubular glass G.

In addition, this embodiment can be changed and carried out as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
-As shown in FIG. 8, the folding step may be executed after the secondary crack extension region C'is formed in the crack C. The secondary crack extension region C'is a kind of crack extension region formed by the crack C naturally extending when the crack C is formed. Even in this case, the base point of the crack extension 20 is stable. Therefore, good quality of the end face 21 of the tubular glass G can be ensured.

-The method of rotating the tubular glass G by a predetermined amount in the process from the crack forming step to the folding step is not limited to the method of forming the tubular glass G while rotating it with the sleeve 8. For example, after forming the crack, another method may be adopted, such as turning the tubular glass G by a predetermined amount using another instrument.

The crack C is not limited to being formed only inside the tubular glass G, and may be exposed on the front surface or the back surface.
The shape of the crack C is not limited to a linear shape on the end face of the glass, and may be changed to another shape such as an arc shape along the circumferential direction of the tubular glass G.

-The width, thickness, inclination, etc. of the crack C can be appropriately changed to an embodiment other than the embodiment.
The line connecting the center Pr in the circumferential direction of the crack C and the axial center Pk of the tubular glass may partially overlap with the line along the direction of the bending stress F (line Lc in the weighting direction).

The laser LA irradiated to the tubular glass G is not limited to the multiphoton absorption laser, and other types of laser LA may be adopted.
-When irradiating the laser LA to form the crack C, any mode of irradiation of the laser LA may be adopted as long as the required crack C can be formed.

The crack extending portion 13 (holding roller 16a) is not limited to the configuration of the embodiment, and may have a configuration capable of applying bending stress to the tubular glass G after crack formation to extend the crack C.

The position of the support roller 15 may be changed to another position, for example, directly under the laser beam irradiation device 12a.
The position of the laser light irradiation device 12a may be changed to another position such as upstream from the holding roller 14.

-The crack formation position is preferably directly above the support roller 15, but may be changed to upstream or downstream.
-The tube glass manufacturing apparatus 1 can appropriately adopt a configuration other than the embodiment.

1 ... tube glass manufacturing device, 6 ... tubular glass cutting device, 15 ... support roller, 16 ... jig, 16a ... holding roller, 19a ... crack end, 21 ... end face, 22 ... folded surface, G ... tubular glass, G '... tube glass, M ... molten glass, LA ... laser, C ... crack, C'... secondary crack extension region, F ... bending stress, Pr ... center (center in the circumferential direction of the crack), Pk ... axis center (tubular) Glass axis center), Lb ... line (line connecting the circumferential center of the crack and the axial center of the tubular glass), θ1 ... angle, S ... confluence.

Claims (7)

The crack forming step of irradiating the tubular glass with a laser to form a crack in the tubular glass, and bending stress are applied to the tubular glass in which the crack is formed by using a jig to extend the crack. It is a tubular glass cutting method including a folding step of cutting a tubular glass.
The crack forming step and the folding step are executed in separate steps that are not synchronized with each other.
In the folding step, the crack is arranged so as to be on the jig side.
A tubular glass cutting method in which the direction of the line connecting the center of the crack in the circumferential direction and the axial center of the tubular glass is different from the direction in which the bending stress is applied using the jig . Of the two angles formed by the line connecting the two crack ends of the crack and the axial center of the tubular glass with respect to the line in the weighting direction, the angle with the smaller absolute value is set to -10 to +10 degrees. The tubular glass cutting method according to claim 1 . The tubular glass cutting method according to claim 1 or 2 , wherein a plurality of tube glasses are manufactured from one tubular glass by carrying out the crack forming step and the folding step on the continuously molded tubular glass. .. The invention according to any one of claims 1 to 3 , wherein the crack forming step and the folding step are carried out on the tubular glass continuously formed by winding the molten glass in the circumferential direction with a sleeve. Tubular glass cutting method. The tubular glass cutting method according to claim 4 , wherein the pulling speed of the tubular glass from the sleeve is set to 0.1 to 10 m / sec. The tubular glass cutting method according to any one of claims 1 to 5 , wherein in the folding step, the tubular glass is cut by the jig while supporting the tubular glass with a support roller. The crack forming step of irradiating the tubular glass with a laser to form a crack in the tubular glass, and bending stress are applied to the tubular glass in which the crack is formed by using a jig to extend the crack. It is a tubular glass cutting method including a folding step of cutting a tubular glass.
After the secondary crack extension region is formed in the crack, the folding step is executed .
In the folding step, the crack is arranged so as to be on the jig side.
A tubular glass cutting method in which the direction of the line connecting the center of the crack in the circumferential direction and the axial center of the tubular glass is different from the direction in which the bending stress is applied using the jig .

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