JP2005119933A - Manufacturing method of optical fiber and stretching unit of glass preform therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an optical fiber which is capable of increasing the net working rate of a stretching unit and enhancing productivity, and a stretching unit of a glass preform using for the method. <P>SOLUTION: In this stretching unit 7 of a glass preform 5, two stretching chucks 27, 28 are equipped locating at different distances in the stretching direction on the stretching line 8, and they alternatively grasp the glass preform 5 and continuously stretch it and, at the same time, the stretched preform 5 is cut at a specified range of its length from the top when the preform reached the length by a cutting device 9 connected to the underside stretching chuck 27. The stretched and cut glass preform 5A is removed one after another from the stretching line 8 with a preform receiving tool 51. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to an optical fiber manufacturing method and a glass base material drawing apparatus used therefor, and in particular, it is not necessary to pause the drawing process even during the cutting process, and the optical fiber can be processed by parallel processing of the drawing process and the cutting process. The present invention relates to an improvement for enabling efficient production of a base material.

  As a method of manufacturing an optical fiber, (1) a first step of obtaining a starting core rod by connecting a seed rod or a dummy rod made of quartz by heating and melting at both ends of a glass rod having a core and a part of a cladding; 2) Second step of depositing the generated glass fine particles on the outer periphery of the starting core rod to form a porous glass body to obtain a composite base material. (3) Heating the composite base material into a transparent glass A third step for obtaining a large-diameter preform (initial glass base material), (4) a fourth step for drawing the corresponding initial glass base material to a predetermined diameter for drawing, and (5) a predetermined diameter in this fourth step. A fifth step of obtaining a stretched base material obtained by cutting the glass base material into a predetermined length, (6) a sixth step of machining the end of the stretched base material into a spindle shape, and (7) a stretch through the sixth step. For wire drawing by welding a dummy bar to one or both ends of the base material It is proposed to sequentially perform a seventh step of forming a fiber preform, and (8) an eighth step of drawing the drawing optical fiber preform to an optical fiber, and the fourth and fifth steps described above. Therefore, a manufacturing apparatus is proposed in which a stretching apparatus that performs the fourth step is combined with a cutting apparatus that cuts a stretched glass base material into a predetermined length by cutting with a cutter blade (for example, a patent). Reference 1).

Japanese Patent Laid-Open No. 10-81535

However, the conventional cutting device that cuts the stretched glass base material to a predetermined length is generally a cutter that cuts the glass base material with a cutter blade, and since it takes time to cut, stretching directly under the furnace body for stretching Online disconnection on the line was difficult.
Another reason why online cutting is difficult is that the glass base material immediately after the stretching process cannot be cut until it is cooled to a constant temperature after the stretching process is interrupted because the glass base material has a considerably high temperature.
Therefore, in the conventional optical fiber manufacturing apparatus, it has been proposed to remove the stretched glass base material from the furnace body, move it to another position off the stretching line, and perform a cutting process offline.

However, in the manufacturing method in which the cutting process is performed off-line, it is necessary to stop the operation of the stretching apparatus in order to remove the stretched glass base material from the furnace body. .
In addition, when the entire glass base material is removed from the furnace body of the stretching device for offline cutting processing, the length that can be stretched from the original glass base material (large-diameter preform) is limited, In this respect as well, there was a problem that productivity was poor.

  The object of the present invention is to eliminate the above-mentioned problem, and while the drawing process is continuously performed in the drawing apparatus on the drawing line of the drawing apparatus that initially draws the glass base material to a predetermined diameter for drawing, the glass base material has been drawn. An optical fiber manufacturing method capable of cutting a glass base material into predetermined lengths and removing the cut out stretched glass base material from the stretching line, thereby increasing the operating rate of the stretching apparatus and improving productivity. And it is providing the extending | stretching apparatus of the glass base material used for it.

The above object is achieved by the following configuration.
(1) In the step of obtaining a plurality of stretched glass preforms for an optical fiber from the initial glass preform, the first stretched glass preform has a predetermined length during the stretching step of stretching the initial glass preform. A cutting device having a first stretching step to secure, and then a second stretching step to secure a second stretched glass base material, and moving at the same speed as the stretching speed during the second stretching step, A glass base material comprising: a cutting step of securing a predetermined length of the stretched glass base material of 1 and cutting the first stretched glass base material cut from the stretched line. Stretching method.

(2) In the above (1), in the second stretching step, the second stretched glass base material is gripped by one stretching chuck, and then below the one stretching chuck, the cutting position A method for stretching a glass base material, characterized in that an upper portion is gripped by the other stretching chuck, and the other stretching chuck is moved at the same speed as the one stretching chuck.

(3) In the above (1), a base material receiver for receiving the first stretched glass base material after cutting is installed below the cutting device, and the first stretched glass base material is confirmed for a predetermined length. After cutting, the base material receiver is removed together with the first stretched glass base material from the stretching line.

(4) In the above (1), in the cutting step, the stretched glass base material is scratched at the cutting position, and a patch is applied to the upper and lower portions of the stretched glass base material that are separated from the cutting position by a predetermined distance. The first stretched glass base material is cut off by applying a pressing tool to a position facing the cutting position on the surface of the stretched glass base material, and pressing the pressing tool into the stretched glass base material. The glass base material is stretched.

(5) A stretching apparatus for heating and stretching a glass base material and cutting out to a predetermined length. While one stretching chuck is in a stretching operation, the other stretching chuck is moved to a new gripping position. While gripping the glass base material, it moves at the same speed as the one gripping chuck, performs stretching, and the one stretching chuck moves to a new gripping position while the other stretching chuck is stretching. A pair of stretching chucks that grip the glass base material, move at the same speed as the other gripping chuck, perform stretching, and continuously stretch the glass base material, and the glass base material And a cutting device for cutting the stretched portion having the predetermined length while moving at a predetermined cutting position at the same speed as the stretching chuck during stretching. Apparatus.

(6) The glass base material stretching apparatus according to (5), wherein the one stretching chuck is controlled to be positioned above the other stretching chuck.

(7) In the above (5), the cutting device applies a cutter blade for scratching the cutting position of the glass base material, and two upper and lower positions separated from the cutting position of the stretched glass base material by a predetermined distance. The first stretched glass has a pair of struts and a pusher that strikes the surface of the stretched glass preform facing the cutting position, and the pusher is pushed into the stretched glass preform. An apparatus for drawing a glass base material, characterized by separating the base material.

(8) The glass base material stretching apparatus according to (5), wherein the patch is a roller having a surface of a heat resistant resin.

(9) In the above (5), the cutting device is a glass base material stretching device in which a base material receiving member for receiving a stretched portion that is cut and dropped is suspended.

The glass preform stretching apparatus described in (5) to (9) above can be used in the optical fiber manufacturing method described in (1) and (2) above.
And in the manufacturing method of the optical fiber as described in said (1), the glass already extended by the predetermined diameter on the extending | stretching line of the extending | stretching apparatus which extends | stretches a glass preform | base_material (a large diameter preform, for example, 50 mm diameter or more) initially. A cutting process for cutting the base material into predetermined lengths is performed, and the cutting process is performed as an online process while being stretched.
Therefore, compared with the conventional optical fiber manufacturing method that has been cut off-line, there is no need to remove the glass base material from the furnace body. There is no need to interrupt.
Therefore, the productivity of the drawn glass base material for drawing can be improved by reducing the work process for removing the glass base material and the like and continuously operating the drawing device.

In addition, every time the glass base material stretched to a predetermined diameter reaches a predetermined length, it is sequentially cut from the front end side by a predetermined length and removed from the stretching line. The length of the material is always maintained within a certain range.
Therefore, even if a manufacturing method in which the stretching apparatus is continuously operated is adopted, the space for the stretching line to be secured below the stretching apparatus is not required to be so long. Production can be realized.

Moreover, the manufacturing method as described in (4) makes a small notch on one side of the outer periphery of the glass base material, and instantaneously applies a shear load to the outer surface of the glass base material from the opposite side, whereby the glass base material The cutting time can be shortened significantly compared to the conventional cutting method in which the glass base material is cut only by cutting with a cutter blade.
Therefore, there is no inconvenience that the stretching speed at the time of continuous stretching must be kept low in order to secure the cutting work time, and the productivity can be further improved by increasing the stretching speed.

In addition, in the case of the glass base material stretching apparatus described in (7) above, the glass base material that has been cut by the cutter blade is added with a push bar by means of an abutment tool that is in contact with the upper and lower two positions across the cut. The movement in the shear load direction is restricted.
Therefore, the shear load from the push rod is not absorbed by the bending of the glass base material, and the concentrated load is efficiently concentrated around the notch, so that the momentary fracture cutting starting from the notch is performed. Can be realized.

  Further, in the glass base material stretching apparatus described in (8) above, if the contact portions of the two bases with the glass base material have a roller having a heat resistant resin surface, the contact portions are rubbed. It is also possible to prevent the outer peripheral surface of the glass base material from being damaged or the flaws from running in an unexpected direction.

  Further, in the glass base material stretching device described in (9) above, if the base material receiving member for receiving the stretched part that is cut and dropped is suspended integrally, the cutting device has a high temperature. Since the glass base material can be received and held, it is not necessary to interrupt the stretching process until the high-temperature glass base material like the conventional device is cooled to a certain temperature, and the operating rate of the stretching apparatus is increased. Productivity.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an optical fiber manufacturing method and a glass base material drawing apparatus used therefor according to the present invention will be described in detail with reference to the drawings.
First, after describing an embodiment of a glass preform stretching apparatus according to the present invention, an optical fiber manufacturing method of the present invention implemented by the stretching apparatus will be described.

  As shown in FIG. 1, a glass base material stretching apparatus 1 according to an embodiment of the present invention is a preform (initially referred to as a glass base material, which has a diameter of 50 mmφ or more, for example. 3) and a stretching device 7 that heat-stretches 3 to a glass base material 5 having a predetermined diameter suitable for processing with a drawing machine, and a stretched high-temperature stretched glass base material 5 is vertically stretched directly under the stretching device 7. A cutting device 9 for cutting on the drawing line 8 and a transfer device 11 for carrying the drawn glass base material 5A (see FIG. 4) cut by the cutting device 9 from the drawing line to another processing position. ing.

  The stretching device 7 has a fitting portion 21 a that initially supports the upper end of the glass base material 3 at the lower end, a support rod 21 that is gripped by the chuck 19 and can be moved up and down with the chuck 19, and a lower end of the support rod 21. A heater 23 that heats the outer periphery of the initial glass base material 3 that is suspended, a furnace body 25 that covers the periphery of the heater 23 and the initial glass base material 3, and a glass base material that is stretched and fed below the furnace body 25. And two stretching chucks 27 and 28 for supporting 5 at two positions separated in the axial direction (stretching direction). The two stretching chucks 27 and 28 are equipped to be individually movable up and down.

  The chuck 19 that holds the support rod 21 can be controlled to move up and down according to the lifting and lowering operations of the stretching chucks 27 and 28 so that the outer diameter of the glass base material 5 is properly maintained.

The initial glass base material 3 to be attached to the stretching device 7 is, for example, (1) connected to both ends of a glass rod having a core and a part of a cladding by heating and melting a quartz seed rod or a dummy rod. A first step of obtaining a starting core rod; (2) a second step of obtaining a composite matrix by depositing the generated glass particles on the outer periphery of the starting core rod to form a porous glass body; and (3) the composite. The base material is formed into a predetermined large diameter by obtaining a third step or the like to obtain a glass base material by heating and forming a transparent glass.
In the present embodiment, it is preferable that the initial glass base material 3 has a diameter of 50 mmφ or more. However, the drawing apparatus suitable for the present embodiment is not limited to the case where the drawn glass preform is obtained from the initial glass preform formed to have a large diameter, but an optical fiber drawn from a single glass preform to a plurality of pieces. It is also suitable for manufacturing.

Here, the configuration and operation of the two drawing chucks 27 and 28 described above will be further described with reference to the optical fiber manufacturing process shown in FIGS.
First, the characteristic operation of the two stretching chucks 27 and 28 will be described. In the two stretching chucks 27 and 28, the other stretching chuck 27 is renewed during the stretching operation of one stretching chuck 28. The glass base material 5 is gripped by moving to a proper gripping position (state of FIG. 4C), and the glass base material 5 is stretched by moving at the same speed as the one of the stretching chucks 28 (FIG. 4 ( d) to the state shown in FIG.
Further, while the other stretching chuck 27 described above is being stretched, one stretching chuck 28 moves to a new gripping position to grip the glass base material 5 (as shown in FIGS. 5E to 5F). State), the glass base material 5 is stretched by moving at the same speed as the other stretching chuck 27 (states of FIGS. 5G to 5H), and the glass base material 5 is continuously stretched.

More specifically, the other stretching chuck 27 located on the lower side of the two stretching chucks 27 and 28 stretches the glass base material 5 heated and stretched by the heater 23 in the furnace body 25. A second reference position H2 gripped at a first reference position H1 on the line (see FIG. 4A) and lowered from the first reference position H1 by a predetermined length L1 in the extending direction (see FIG. 4B). By extending the glass base material 5 by descending at a predetermined speed until the glass base material 5 is released, returning to the first reference position H1, and repeatedly holding the glass base material 5 again. The glass base material heated by the heater 23 in the furnace body 25 is intermittently stretched by a predetermined length L1.
For example, the predetermined length L1 may be 700 to 1300 mm.

In the second stretching chuck 28 positioned at the third reference position H3 (see FIG. 4B) above the first reference position H1 of the other stretching chuck 27, the first stretching chuck 27 is the first stretching chuck 27. Until the return from the second reference position H2 to the first reference position H1, the glass base material 5 heated by the heater 23 in the furnace body 25 is gripped and lowered at a predetermined speed. In place of 27, the glass base material 5 is stretched.
At this time, as shown in FIG. 4C, the distance L2 by which one of the stretching chucks 28 is lowered until the other stretching chuck 27 returns from the second reference position H2 to the first reference position H1. Is smaller than the separation distance L3 between the third reference position H3 and the first reference position H1.
Therefore, when the other stretching chuck 27 returns from the second reference position H2 to the first reference position H1, the fourth reference position H4 reached by the one stretching chuck 28 is higher than the first reference position H1. Yes, the pair of stretching chucks do not interfere with each other.

As shown in FIG. 2, the cutting device 9 is connected to the other stretching chuck 27 located on the lower side in the stretching direction, and moves up and down integrally with the other stretching chuck 27.
The cutting device 9 is disposed at a position facing the cutter blade 41 with the glass base material 5 sandwiched between the cutter blade 41 for cutting one side of the outer periphery of the glass base material 5, and perpendicular to the stretching direction. The push rod 43 that applies a shear load to the outer periphery of the material 5 and when the push rod 43 applies a shear load to the glass base material 5, the glass base material 5 is applied to two positions above and below the notch made by the cutter blade 41. Are formed of two support tools 45 and 46 that support the components, and a support frame 48 that supports these components.
The support frame 48 is a structure connected to the support frame 35 of the other stretching chuck 27.
Note that the distance between the two abutments 45 and 46 that are spaced apart from the push rod 43 acts to restrain the fracture surface of the glass base material 5 described later from being inclined with respect to the axis of the glass base material 5. Have

The cutter blade 41 is a rotary blade, and makes a shallow cut on the surface of the glass base material 5 by cutting.
The cutter blade 41, the push rod 43, and the abutting tools 45 and 46 are all equipped so as to be able to advance and retract in a direction perpendicular to the axis of the glass base material 5.
After cutting the surface of the glass base material 5, the cutter blade 41 is retracted to a position separated from the glass base material 5. Pressed.
When the pressing of the abutments 45 and 46 is completed, the push bar 43 is brought into contact with the outer surface of the glass base material 5 and a shear load is applied to break the glass base material 5 at the cut portion.
In the case of the present embodiment, the two abutments 45 and 46 are equipped with rollers 43 a, 45 a and 46 a having a surface of a heat resistant resin as contact portions with the glass base material 5.

  In the cutting device 9 described above, the push bar 43 applies a shear load to the glass base material 5, but in addition to the shear load, ultrasonic waves are superimposed on the outer surface of the glass base material 5, thereby forming the glass base material. It is also conceivable to make cutting 5 easier.

The transfer device 11 includes a base material holder 51 that can be attached to and detached from the cutting device 9, and an extension line 8 directly below the cutting device 9 and other processing positions that are separated from the extension line 8 (for example, (Not shown) for moving the base material receiver 51 between the stretched glass base material storage position and the like.
The base material receiver 51 is a bottomed cylindrical container that accommodates the glass base material 5 having a predetermined length L1, and as shown in FIG. By being hooked on a locking hook 48 a protruding from the lower surface of the support frame 48, it is attached on the extension line 8 directly below the cutting device 9.
In the present embodiment, the transfer device 11 is configured such that the base material receiver 51 is mounted on the cutting device 9 and moves together with the cutting device 9, but only the base material receiver 51 may move.

Next, an optical fiber manufacturing method performed by the optical fiber manufacturing apparatus 1 will be described with reference to FIGS.
First, as shown in FIG. 4A, the stretching apparatus 7 places the two stretching chucks 27 and 28 at the initial positions H1 and H3, respectively, and initially sets the glass base material 3 in the furnace body 25. Then, the end of the glass base material 5 drawn out below the furnace body 25 is held by the other stretching chuck 27 located on the lower side, and the other stretching chuck 27 as shown in FIG. 4B. Stretching process is started by descending and a first stretching step for securing a predetermined length of the first stretched glass base material is performed.
When the glass base material 5 can be secured to the predetermined length L1, the other stretching chuck 27 releases the gripping of the glass base material 5, and at the same time, the other stretching tool that has been waiting at the third reference position H3. The chuck 28 grips the glass base material 5 and switches to the stretching of the second stretching step for securing a predetermined length of the second stretched glass base material by lowering one gripping chuck 28.

In the second stretching step, the other stretching chuck 27 is returned to the first reference position H1 and returned to the state in which the glass base material 5 is gripped, as shown in FIG. Then, the other stretching chuck 27 that has returned to the first reference position H <b> 1 starts to descend at the stretching speed of the glass base material 5 by the one stretching chuck 28. Further, a base material holder 51 constituting the transfer device 11 is suspended from the lower surface of the other stretching chuck 27 that has returned to the first reference position H1, and protrudes below the other stretching chuck 27. The glass base material 5 having a predetermined length L1 is accommodated in the base material receiver 51.
Next, as shown in FIG. 4D, the cutting device 9 is operated to cut the range of the predetermined length L1 from the tip of the glass base material 5 that has been stretched to a predetermined diameter, and the first stretched glass that has been cut. The base material 5A is received by the base material holder 51.
As shown in FIG. 5 (e), the base material holder 51 that has received the cut first drawing glass base material 5A is removed from the bottom of the cutting device 9 and moved to another processing position. First glass base material 5A for stretching is removed from the stretching line.

When the base material holder 51 that has received the cut first stretched glass base material 5A is removed from the cutting device 9, as shown in FIG. 5 (e), one of the stretching chucks that has been stretched until then. 28 cancels | releases holding | grip of the glass base material 5, returns to the 3rd reference position H3 which is an initial position, and waits in an unheld state.
While the one stretching chuck 28 is returning, as shown in FIG. 5 (f), the other stretching chuck 27 continues to descend while holding the glass base material 5 to continue stretching.

When the other stretching chuck 27 is lowered to the first reference position H2, the glass preform 5 is gripped by one stretching chuck 28, and the one stretching chuck 28 is lowered so that the glass preform 5 The stretching of the second stretching process is started. Simultaneously with the start of stretching by the one stretching chuck 28, the other stretching chuck 27 releases the gripping of the glass base material 5 and returns to the first reference position H1 as shown in FIG. 5 (g). . Then, under the other stretching chuck 27 returned to the first reference position H1, a base material receiving tool 51 is mounted via a cutting device 9, and the stretched glass base material 5 having a predetermined length L1 is accommodated. To do.
And as shown in FIG.5 (h), the glass base material 5 of the predetermined length L1 accommodated in the base material holder 51 is cut | disconnected by the cutting device 9, and while the glass base material 3 exists initially, The processes (e) to (h) are repeated in order.

In the optical fiber manufacturing method according to the embodiment described above, the glass base material 5 that has been stretched to a predetermined diameter is cut by a predetermined length on the stretching line 8 of the stretching device 7 that initially stretches the glass base material 3. The process is performed, and the cutting process is an online process.
Therefore, compared with the conventional optical fiber manufacturing method that has been cut off-line, there is no need to remove the glass base material 5 and the initial glass base material 3 from the furnace body 25, and the cutting can be performed in a short time. If realized, there is no need to interrupt the operation of the stretching device 7.
Therefore, the productivity of the drawn glass base material 5A for drawing can be improved by reducing work steps such as removal of the glass base material 5 and continuous operation of the drawing device 7.

Further, each time the glass base material 5 stretched to a predetermined diameter reaches a predetermined length L1, it is sequentially cut by the cutting device 9 at a length of the predetermined length L1 from the tip side, and is transferred from the stretching line 8 by the transfer device 11. Since it is removed, the length of the glass base material 5 that hangs down below the stretching device 7 is always maintained within a certain range.
Therefore, even if the manufacturing method that can continuously stab the stretching apparatus 7 is adopted, the space for the stretching line 8 to be secured below the stretching apparatus 7 is not so long, and the efficiency of the glass base material 5 can be reduced with a compact apparatus installation space. Production can be realized.

In the manufacturing method of the above embodiment, a small cut is made on one side of the outer periphery of the glass base material 5 and a shear load is instantaneously applied to the outer surface of the glass base material 5 from the opposite side, whereby the glass base material is obtained. 5 is instantaneously broken and cut, and the cutting time can be greatly shortened as compared with the case of adopting a conventional cutting method in which the glass base material 5 is cut only by cutting with a cutter blade.
Therefore, in order to secure the time required for the cutting time, there is no inconvenience that the stretching speed at the time of continuous stretching must be kept low, and the productivity can be further improved by increasing the stretching speed.
At present, the take-up speed of the other stretching chuck 27 and one stretching chuck 28 is about 40 mm / min. However, in this embodiment, the cutting operation can be completed in a very short time. Specifically, it is not impossible to increase the take-up speed of each stretching chuck to about 100 mm / min.

Further, in the case of the optical fiber manufacturing apparatus 1 of the above embodiment, when the cutting device 9 cuts the glass base material 5, the glass base material 5 that has been cut by the cutter blade 41 has an upper and lower sides sandwiching the cut. The abutting tools 45 and 46 are brought into contact with the two positions to restrain the movement in the shear load direction applied by the push rod 43.
Accordingly, the shear load is not absorbed from the push rod 43 due to the bending of the glass base material 5 and the like, and the concentrated load is efficiently concentrated around the notch, so that the instantaneous glass mother starting from the notch is used. Breaking and cutting of the material 5 can be realized.

  Moreover, since the contact part with the glass base material 5 of the two holding tools 45 and 45 is equipped with the rollers 45a and 46a which have a heat resistant resin surface, a damage | wound is carried out to the glass base material outer peripheral surface by the friction of a contact part. It is also possible to prevent sticking. Preferably, the push bar 43 is also provided with a roller 43a having a heat resistant resin surface at the tip.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of one Embodiment of the optical fiber manufacturing apparatus which enforces the manufacturing method of the optical fiber which concerns on this invention. FIG. 2 is an enlarged view around a cutting device mounted on the optical fiber manufacturing apparatus shown in FIG. 1. It is a block diagram of the base material holder which can be attached or detached to the cutting device shown in FIG. It is process explanatory drawing of the extending | stretching apparatus of the glass base material used with the manufacturing apparatus of the optical fiber shown in FIG. It is process explanatory drawing of the extending | stretching apparatus of the glass base material used with the manufacturing apparatus of the optical fiber shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber manufacturing apparatus 3 Preform 5 Preform 7 Stretching apparatus 9 Cutting apparatus 11 Transfer apparatus 19 Chuck 23 Heating heater 25 Furnace body 27 First stretching chuck 28 Second stretching chuck 41 Cutter blade 43 Push rod 43a roller 45, 46 abutment tool 45a, 46a roller 48 support frame 48a locking hook 51 preform receiver 51a suspension ring

Claims (9)

In the process of obtaining a stretched glass preform for a plurality of stretched optical fibers from the initial glass preform,
During the stretching step of stretching the initial glass base material, a first stretching step for securing a predetermined length of the first stretched glass base material and a second stretching step for securing a second stretched glass base material are provided thereafter. And
In a cutting device that moves at the same speed as the stretching speed during the second stretching step, a cutting step that secures and cuts the first stretched glass preform with a predetermined length;
And a removal step of removing the cut first drawn glass preform from the drawing line. In the second stretching step, the second stretched glass base material is gripped by one stretching chuck, and thereafter, below the one stretching chuck, and above the cutting position by the other stretching chuck. 2. The method of manufacturing an optical fiber according to claim 1, wherein the other stretching chuck is moved at the same speed as the one stretching chuck. A base material receiver for receiving the first stretched glass base material after cutting is installed below the cutting device, the first stretched glass base material is checked for a predetermined length and cut, and then the base material receiver is mounted. The optical fiber manufacturing method according to claim 1, wherein the optical fiber is removed from the drawing line together with the first drawn glass preform. In the cutting step, the stretched glass base material is scratched at the cutting position, and a tool is applied to two upper and lower portions of the stretched glass base material that are separated from the cutting position by a predetermined distance. 2. The optical fiber according to claim 1, wherein the first stretched glass preform is separated by applying a pusher to a position opposite to the cutting position and pushing the pusher into the stretched glass preform. Production method. It is a stretching device for heating and stretching a glass base material and cutting it to a predetermined length,
While one of the stretching chucks is being stretched, the other stretching chuck moves to a new gripping position, grips the glass base material, moves at the same speed as the one gripping chuck, and stretches. The other stretching chuck is moved to a new gripping position while the other stretching chuck is in a stretching operation, grips the glass base material, and moves at the same speed as the other gripping chuck, A pair of stretching chucks for stretching and continuously stretching the glass base material;
A glass having a cutting device that cuts the stretched portion of the glass base material having the predetermined length while moving at a predetermined cutting position at the same speed as the stretching chuck being stretched. Base material stretching equipment. 6. The glass base material stretching apparatus according to claim 5, wherein the one stretching chuck is controlled to be positioned above the other stretching chuck. The cutting device includes a cutter blade for scratching the cutting position of the glass base material, a pair of upper and lower application tools that are applied to two upper and lower positions away from the cutting position of the stretched glass base material, and the stretched glass. A pressing tool that hits a position facing the cutting position on the surface of the base material,
The glass base material stretching apparatus according to claim 5, wherein the first stretched glass base material is separated by pressing the pusher into the stretched glass base material. 6. The glass base material stretching apparatus according to claim 5, wherein the patch is a roller having a surface of a heat resistant resin. 6. The glass base material stretching device according to claim 5, wherein a base material receiving member for receiving the stretched portion to be cut and dropped is suspended from the cutting device.

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