JP2020019693A - Tubular glass cutting method, and tubular glass - Google Patents

Abstract

To provide a tubular glass cutting method capable of securing excellent quality of an end surface of the tubular glass; and to provide the tubular glass.SOLUTION: When cutting a tubular glass G into a prescribed length, first of all, a laser beam is irradiate to the tubular glass G from a laser beam irradiation device 12a to form a crack (crack formation step). After forming a crack, a pressing roller 16a is brought into contact with the tubular glass G, to thereby elongate the crack C, and to split the tubular glass G at the periphery of the crack (splitting step). In this case, the crack formation step and the splitting step are executed in each different step asynchronously respectively.SELECTED DRAWING: Figure 4

Description

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

  BACKGROUND ART A tubular glass cutting method for cutting (roughly cutting) a continuous tubular glass into a predetermined length to form a tube glass is well known. In this tubular glass cutting method, for example, cracks (scribes) are formed in a tubular glass by a laser while constantly applying a bending stress to the tubular glass, and thereafter, the cracks are extended by applying a bending stress to the tubular glass to break the cracks. 2. Description of the Related Art A laser-type cutting method for obtaining a tube glass having a predetermined length is well known (see Patent Document 1 and the like).

JP 2017-77991 A

  However, in the case of the laser cutting method, when a laser beam is irradiated while applying bending stress to the cracked tubular glass to be broken, the starting position of the extending crack is not stable, and the end face (folding) of the tubular glass is not stable. In some cases, it was not possible to ensure good quality of the surface), and some countermeasures were required.

  An object of the present invention is to provide a tubular glass cutting method and a tubular glass capable of ensuring good quality of an end face of the tubular glass.

  The tubular glass cutting method to solve the above problems, a crack forming step of irradiating a laser to the tubular glass to form a crack in the tubular glass, by applying a bending stress to the tubular glass formed with the cracks, A breaking step of extending the crack to cut the tubular glass, wherein the crack forming step and the breaking step are each performed in a separate step that is not synchronized.

  According to this configuration, since the crack forming step and the breaking step are not synchronized, when the cracked tubular glass is cut in the breaking step, the crack is extended from a stable crack end as a base point. It is possible to perform a splitting process. Thus, if the crack extension base point is stabilized, the distance from the crack extension base point to the end point is stabilized. For this reason, since the cutting in the step of folding the tubular glass is standardized, good quality of the glass end can be ensured.

  In the tubular glass cutting method, a direction of a line connecting a circumferential center of the crack and an axial center of the tubular glass is preferably different from a direction in which the bending stress is applied. According to this configuration, when the tubular glass is cut by the bending stress, the bending stress concentrates on or near the crack end, and the crack easily extends from the crack end. As described above, since the crack can be extended from the 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, an angle formed by a line connecting one crack end of the crack and an axis center of the tubular glass to the line in the load direction may be 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 that a plurality of tubular glasses are manufactured from one tubular glass by performing the crack forming step and the folding step on the continuously formed tubular glass. According to this configuration, it is possible to manufacture a plurality of tube glasses with 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 performed on the tubular glass formed continuously while the molten glass is wound in a circumferential direction by a sleeve. According to this configuration, the direction of the line connecting the center in the circumferential direction of the crack and the axial center of the tubular glass is made different from the direction in which the bending stress is applied by utilizing the formation of the tubular glass while rotating the sleeve. It becomes possible.

  In the tubular glass cutting method, it is preferable that a drawing speed of the tubular glass from the sleeve is set to 0.1 to 10 m / sec. According to this configuration, it is possible to efficiently cut the tubular glass.

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

  The tubular glass cutting method to solve the above problems, a crack forming step of irradiating a laser to the tubular glass to form a crack in the tubular glass, by applying a bending stress to the tubular glass formed with the cracks, A breaking step of extending the crack to cut the tubular glass, wherein the breaking step is performed after a secondary crack extension area is formed in the crack. According to this configuration, it is possible to more stably extend the crack from the base point, and thus it is possible to ensure good quality of the glass end.

  The tube glass that solves the above problems has a crack formed by laser irradiation, a split surface formed by extending the crack by bending stress, and a confluence of a crack extension extending from an end of the crack. At the end face in the axial direction, and a line connecting the circumferential center of the crack and the junction is formed so as not to pass through the axial center.

  ADVANTAGE OF THE INVENTION According to this invention, the favorable quality of the end surface of a tubular glass can be ensured.

The block diagram of the tube glass manufacturing apparatus of one Embodiment. The block diagram of a tubular glass cutting apparatus. (A), (b) is explanatory drawing of a crack formation process. (A), (b) is explanatory drawing of a folding process. Sectional drawing of a tube glass. FIG. 4 is an explanatory diagram showing a directional relationship between a laser irradiation direction and bending stress for cutting. FIG. 4 is an explanatory diagram showing an angle formed by a crack end with respect to a line in a direction in which bending stress is applied. FIG. 9 is a partially enlarged cross-sectional view showing a secondary crack extension region of another example.

Hereinafter, an embodiment of a tubular glass cutting method and a tubular glass will be described with reference to FIGS.
As shown in FIG. 1, a tube glass manufacturing apparatus 1 includes a glass melting furnace 2 for melting a glass raw material to produce a molten glass M, a muffle furnace 3 for drawing and molding the molten glass M into a tube, and a muffle furnace 3. An annealer 4 for annealing (heat-treating) the tubular glass G (continuous tubular glass) sent from the company, and a tube drawing device 5 for forming the tubular glass G after the annealing by tube drawing. Further, the tube glass manufacturing device 1 includes a tube glass cutting device 6 for cutting the tube glass G pulled by the tube drawing device 5, and a conveyor 7 for transporting the cut tube glass G '.

  The muffle furnace 3 includes a sleeve 8 that rotates around the axis L1 to form the molten glass M into a tube (tubular glass G). The sleeve 8 is made of, for example, a cylindrical refractory. The sleeve 8 is partially formed in a tapered shape, and is arranged with the small-diameter end 9 of the tapered portion obliquely downward. The sleeve 8 is rotated by a driving device 11 connected via a shaft 10, thereby winding the molten glass M supplied from the glass melting furnace 2 into a cylindrical shape, and forming a tubular shape from the small-diameter end 9. Draw out. The molten glass M drawn into a tubular shape is continuously drawn out of the muffle furnace 3 as a tubular glass G.

The annealer 4 removes distortion of the tubular glass G by a predetermined annealing process. The annealing temperature and the heating time are set to various values as needed.
The pipe drawing device 5 pulls the molten glass M drawn out into a tube in the muffle furnace 3 and the tube glass G passing through and through the annealer 4 at a constant speed, thereby cutting the tube glass G into a tube glass cutting device 6. Transport to The pipe drawing device 5 of the present example is adjusted to have a predetermined outer diameter by pulling the pipe to the downstream side while holding the upper and lower portions of the tubular glass G by a pair of transport belts (not shown). The tubular glass G is transported to the tubular glass cutting device 6. Further, by increasing the speed of the pair of conveyor belts, the speed at which the molten glass M is drawn out of the muffle furnace 3 as the tubular glass G can be increased.

  As shown in FIG. 2 to FIG. 4, the tubular glass cutting device 6 applies a bending stress F after forming a crack C (also referred to as a scribe) on the tubular glass G by a laser LA, thereby causing the tubular glass G to have a predetermined length. Then, it is cut into a tube glass G '. In this case, the tubular glass cutting device 6 includes a crack forming portion 12 that forms a crack C in a part of the tubular glass G in a 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 extending portion 13 for breaking G;

  As described above, according to the tubular glass cutting method of the present example, the process of forming the crack C in the tubular glass G by the crack forming unit 12 (the crack forming process) and the bending stress on the tubular glass G after the formation of the crack by the crack extending unit 13 are performed. A step (folding step) of cutting the tubular glass G by adding the F to extend the crack C. Further, in the case of this example, the crack forming step and the splitting step are each performed in separate steps that are not synchronized.

  The crack forming section 12 is a laser beam irradiation device 12a that forms a crack C in the tubular glass G by the laser LA. The laser beam irradiation device 12a is preferably, for example, a multiphoton absorption laser. The laser beam irradiation 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 includes a holding roller 14 for holding the conveyed tubular glass G from one side, a support roller 15 for supporting the tubular glass G from the other side, and folding the tubular glass G in contact with the tubular glass G. A breaking jig 16 (pressing roller 16a). The holding roller 14, the support roller 15, and the pressing 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 position 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 an axis P (the direction of the arrow A in FIG. 2) at the center of the shaft portion 17, and at both ends of the shaft portion 17, protrusions 18 that come into contact with the tubular glass G are provided. . The pressing roller 16a rotates at a constant speed using a motor or the like as a drive source when the tubular glass G is processed.

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 transported to the crack forming position, the laser LA is applied to the tubular glass G from the laser light irradiation device 12a, and a crack C is formed in the tubular glass G. (Crack forming step). The laser LA is applied to the tubular glass G at a focal length that reaches the inside of the tubular glass G.

  As shown in FIG. 3B, the laser beam irradiation device 12a of the present 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. Thus, a predetermined crack C is formed. Since the tubular glass G is sent out while being rotated by the sleeve 8 in the circumferential direction, the tubular glass G is irradiated while the focal length of the laser LA is adjusted, and a crack C is formed. In the case of this example, the crack C is formed in a straight line extending in a direction perpendicular to a 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 axial center Pk of the tubular glass G, is preferably set to 1 to 50 mm. .

  As shown in FIGS. 4A and 4B, after a crack C is formed in the tubular glass G, the tubular glass G is transported to a breaking position, and the tubular glass G is broken at a predetermined length (folding). 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 formed in the circumferential direction of the tubular glass G. At a position shifted by a predetermined distance. That is, when the tubular glass G reaches the breaking position, the center Pr of the crack C moves a predetermined distance in the circumferential direction as compared with when the crack C is formed.

  When the tubular glass G is transported to the folding position, the pressing roller 16a rotates in the folding direction A about the axis P, so that the projection 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 protruding portion 18 comes into contact with the vertex of the tubular glass G (the intersection of the straight line extending in the vertical direction passing through the axis center Pk and the tubular glass G), and the bending stress F in the vertical downward direction is reduced. Added to glass G. A 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.

  As described above, after the laser LA is irradiated between the holding roller 14 and the support roller 15, the protrusion 18 contacts the tubular glass G on the downstream side of the support roller 15 until the laser LA irradiation ends. No bending stress F is applied to the tubular glass G. Therefore, the crack forming step and the splitting step can be executed in separate steps that are not synchronized.

  When a bending stress F is applied to the tubular glass G, the crack C extends in both the clockwise direction and the counterclockwise direction in FIG. 4B with the end of the crack C (the crack end 19a) as a base point. Here, the 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”) are defined as a portion supported by the support roller 15 as a junction S. , These crack extensions 20a, 20b extend. 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 junction S, and the tubular glass G is divided at the timing of the merge. You. In this way, the continuous tubular glass G is cut at a predetermined length to form a tubular glass G '. Therefore, the crack C, the split surface 22, and the junction S exist on the axial end surface 21 of the tubular glass G.

  After breaking the tubular glass G, a tubular glass G 'is manufactured from the remaining tubular glass G by a similar procedure. Also in this case, first, the crack C is formed again in the tubular glass G, and is conveyed again to the breaking position. Subsequently, of the two protrusions 18 of the pressing roller 16a, another rotation other than the one used for the previous splitting hits the tubular glass G due to the rotation about the axis P, 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 the irradiation of the laser LA, a split surface 22 formed by extending the crack C by the bending stress F, and a crack extending from each end of the crack C. It has a junction S of the extensions 20a, 20b. In addition, the tube glass G 'of this example is formed such that the line La connecting the circumferential center Pr of the crack C and the junction S does not pass through the axial 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 breaking step are not synchronized, when the tubular glass G on which the crack C is formed is cut in the breaking step, the crack C is formed based on the crack end 19a. It is possible to extend and fold. Thus, if the base point of the crack extension 20 is stabilized, the distance from the base point of the crack extension 20 to the end point (the junction S of the crack extensions 20a and 20b) is stabilized. For this reason, since the cutting in the process of breaking the tubular glass G is standardized, good quality of the end face 21 of the tubular glass G can be ensured. When the crack forming step and the splitting step are synchronized, the crack C is extended by the bending stress F at the same time as the formation of the crack C by the laser LA, so that the base point of the crack extension 20 and the end point (the crack extension 20a, 20b The distance to the junction S) is not stable.

  FIG. 6 shows the directional relationship between the irradiation direction of the laser LA and the bending stress F for 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 are made asynchronous and the tubular glass G is drawn out while being rotated by the sleeve 8. The line Lb connecting the circumferential center Pr of the crack C and the axial center Pk of the tubular glass G has a different direction with respect to the load 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 concentrates on the crack end 19a or in the vicinity thereof, and the crack extension easily occurs from the crack end 19a. Thus, the crack C can be extended from the stable base point. As described above, the crack C can be extended from the stable base point, so that the cutting of the tubular glass G is standardized. Therefore, in this regard, it is advantageous to ensure good quality of the end face 21 of the tubular glass G.

  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 to the line Lc in the load direction of the bending stress F is set to -10 to +10 degrees. ing. The crack end 19a for which the angle is set is defined by the angle formed by the line connecting the axis Lk of the tubular glass G to the line Lc in the direction in which the bending stress F is applied, of the two crack ends 19a and 19b. The crack end with the smaller absolute value is used. In this case, the crack C easily extends 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 load 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, a plurality of tube glasses G 'with stable quality of the end face 21 (glass end) can be manufactured from one tubular glass G.

  In the case of this example, the molten glass M is formed as a tubular glass G by feeding the molten glass M downstream by the pipe drawing device 5 while winding the molten glass M in the circumferential direction by the sleeve 8, and is wound in the circumferential direction. A crack forming step and a folding step are performed on the continuously formed tubular glass G. Therefore, 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 circumferential center Pr 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 drawing 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 conveyor belts in the pipe drawing device 5.

  In the folding step, the jig 16 cuts the tubular glass G while supporting the tubular glass G with the support rollers 15. Therefore, since the tubular glass G can be broken by the jig 16 with the support roller 15 as a fulcrum, the tubular glass G can be easily cut.

The present embodiment can be modified and implemented 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, after the secondary crack extension area C 'is formed in the crack C, the folding step may be performed. The secondary crack extension region C ′ is a type of crack extension region formed by the natural extension of the crack C when the crack C is formed. Even in this case, the base point of the crack extension 20 is stabilized. 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 a method utilizing forming while rotating the tubular glass G by the sleeve 8. For example, after the crack is formed, another method such as turning the tubular glass G by a predetermined amount using another tool may be adopted.

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 glass end face, 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 modes 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 the line along the direction of the bending stress F (the line Lc in the load direction).

The laser LA applied to the tubular glass G is not limited to the multiphoton absorption laser, and another type of laser LA may be employed.
When forming the crack C by irradiating the laser LA, the laser LA may be irradiated in any manner as long as the required crack C can be formed.

  The crack extending portion 13 (pressing roller 16a) is not limited to the configuration of the embodiment, and may be any configuration that can apply a 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, immediately below the laser beam irradiation device 12a.
The position of the laser beam irradiation device 12a may be changed to another position such as upstream of the holding roller 14.

The crack formation position is desirably directly above the support roller 15, but may be changed upstream or downstream.
-The tube glass manufacturing apparatus 1 can employ | adopt the structure other than an Example suitably.

  DESCRIPTION OF SYMBOLS 1 ... Tube glass manufacturing apparatus, 6 ... Tubular glass cutting apparatus, 15 ... Support roller, 16 ... Jig, 16a ... Holding roller, 19a ... Crack end, 21 ... End face, 22 ... Folding face, 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 crack), Pk ... axial center (tubular) Lb... Line (line connecting the center in the circumferential direction of the crack and the axial center of the tubular glass), θ1... Angle, S.

Claims (9)

A crack forming step of irradiating a laser to the tubular glass to form a crack in the tubular glass, and applying a bending stress to the tubular glass in which the crack is formed, thereby extending the crack and cutting the tubular glass. A method of cutting a tubular glass, comprising a folding step,
A tubular glass cutting method in which the crack forming step and the folding step are each performed in separate steps that are not synchronized. The tubular glass cutting method according to claim 1, wherein a direction of a line connecting a circumferential center of the crack and an axial center of the tubular glass is different from a direction in which the bending stress is applied. The tubular glass cutting according to claim 2, wherein an angle formed by a line connecting one crack end of the crack and an axial center of the tubular glass to the line in the load direction is set to -10 to +10 degrees. Method. For the continuously formed tubular glass, by performing the crack forming step and the folding step, to produce a plurality of tube glasses from one tubular glass according to any one of claims 1 to 3 The method for cutting tubular glass according to the above. The crack forming step and the folding step are performed on the tubular glass formed continuously while the molten glass is wound in a circumferential direction by a sleeve, according to any one of claims 1 to 4. Tubular glass cutting method. The tubular glass cutting method according to claim 5, wherein a drawing 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 6, wherein, in the folding step, the tubular glass is cut by a jig while supporting the tubular glass with a support roller. A crack forming step of irradiating a laser to the tubular glass to form a crack in the tubular glass, and applying a bending stress to the tubular glass in which the crack is formed, thereby extending the crack and cutting the tubular glass. A method of cutting a tubular glass, comprising a folding step,
A method for cutting a tubular glass, wherein the folding step is performed after a secondary crack extension region is formed in the crack. Tube glass having a crack formed by laser irradiation, a split surface formed by extending the crack by bending stress, and a confluence of crack extension extending from an end of the crack on an axial end surface. And
A tube glass in which a line connecting the circumferential center of the crack and the junction is formed so as not to pass through the axial center.