JP2000169171A - Method for drawing optical fiber preform - Google Patents
Method for drawing optical fiber preformInfo
- Publication number
- JP2000169171A JP2000169171A JP34540998A JP34540998A JP2000169171A JP 2000169171 A JP2000169171 A JP 2000169171A JP 34540998 A JP34540998 A JP 34540998A JP 34540998 A JP34540998 A JP 34540998A JP 2000169171 A JP2000169171 A JP 2000169171A
- Authority
- JP
- Japan
- Prior art keywords
- outer diameter
- measured
- optical fiber
- speed
- heating source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/01205—Manufacture of preforms for drawing fibres or filaments starting from tubes, rods, fibres or filaments
- C03B37/01225—Means for changing or stabilising the shape, e.g. diameter, of tubes or rods in general, e.g. collapsing
- C03B37/0124—Means for reducing the diameter of rods or tubes by drawing, e.g. for preform draw-down
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は光ファイバ用ガラス
母材の延伸方法に関する。The present invention relates to a method for drawing a glass preform for an optical fiber.
【０００２】[0002]
【従来の技術】光ファイバを製造するには、通常ＶＡＤ
法、ＯＶＤ法等で合成された光ファイバ用ガラス母材を
延伸，縮径して所定サイズの延伸体として、この延伸体
を線引炉中で加熱溶融しつつ一定の張力をかけて設計サ
イズの光ファイバに線引する。延伸体の寸法精度はその
ままファイバの寸法精度に影響し、ファイバの寸法不良
はファイバと光源との結合状態、ファイバ間の接続、コ
ネクタ等に悪影響を及ぼす。従って延伸体プリフォーム
の外径を一定にすることは、光ファイバ外径精度向上の
ために非常に重要である。2. Description of the Related Art An optical fiber is usually manufactured by using a VAD.
The glass base material for optical fibers synthesized by the OVD method or the like is drawn and reduced in diameter to obtain a drawn body of a predetermined size. The drawn body is heated and melted in a drawing furnace while applying a constant tension to a designed size. To an optical fiber. The dimensional accuracy of the drawn body directly affects the dimensional accuracy of the fiber, and the dimensional defect of the fiber adversely affects the coupling state between the fiber and the light source, the connection between the fibers, the connector, and the like. Therefore, it is very important to make the outer diameter of the stretched preform constant to improve the accuracy of the outer diameter of the optical fiber.
【０００３】従来技術として、図５に示すように送り込
み用チャック２′で光ファイバ用母材１′の一端を水平
方向に把持して回転させながら加熱源４′で加熱して延
伸し、延伸された他端６′は引き取り用チャック７′で
把持し、チャック２′を右方へ定速で移動（送り出し）
しながら外径測定器８′で測定した延伸体５′の外径
（外径測定値）の設定値からのずれを演算装置９′で演
算し、この結果に応じて制御装置１０′によりモーター
１１′を制御してチャック７′の右方への移動（引き取
り）速度を制御する方法が知られている。As a prior art, as shown in FIG. 5, one end of an optical fiber preform 1 'is horizontally held by a feeding chuck 2' and rotated while being heated and stretched by a heating source 4 'while rotating. The other end 6 'is gripped by the pick-up chuck 7' and the chuck 2 'is moved rightward at a constant speed (delivery).
The deviation from the set value of the outer diameter (measured outer diameter) of the stretched body 5 'measured by the outer diameter measuring device 8' is calculated by the arithmetic unit 9 ', and the motor is controlled by the control unit 10' according to the result. There is known a method of controlling the moving speed of the chuck 7 'to the right (drawing) by controlling the speed 11'.
【０００４】また、この改良法として特公昭５９−１８
３２５号公報（文献）には、図６に示すように、光フ
ァイバ用母材１′の両端をそれぞれチャック２′，７′
で把持し、引落部３′を加熱源４′で加熱溶融して引き
延ばす光ファイバ用母材の製造方法であって、加熱源
４′を固定しておき延伸終了側のチャック７′を定速で
移動するか、またはチャック７′を固定して加熱源４′
を定速移動し、かつ前記引落部３′の途中の外径を測定
して該外径が一定になるように延伸開始側のチャック
２′の移動速度を制御して所定の寸法のガラス母材を得
る方法が提案されている。また延伸体５′の外径と引落
部３′の外径の両方を測定して制御する方法についても
提案されている。なお、図５と図６において共通する符
号は同意である。As an improved method, Japanese Patent Publication No. 59-18 / 1984 has been proposed.
No. 325 (literature) discloses that, as shown in FIG. 6, both ends of an optical fiber preform 1 'are chucked 2' and 7 ', respectively.
This is a method for manufacturing a preform for an optical fiber in which the drawn-down portion 3 'is heated and melted and stretched by a heating source 4', and the heating source 4 'is fixed and the chuck 7' on the drawing end side is moved at a constant speed. Or the chuck 7 'is fixed and the heating source 4'
Is moved at a constant speed, and the outer diameter in the middle of the pull-down portion 3 'is measured, and the moving speed of the chuck 2' on the stretching start side is controlled so that the outer diameter is constant, thereby controlling the glass base having a predetermined size. A method for obtaining a material has been proposed. There has also been proposed a method of measuring and controlling both the outer diameter of the stretched body 5 'and the outer diameter of the drawn part 3'. Note that the same reference numerals in FIG. 5 and FIG.
【０００５】また、特開平６−１２７９６３号公報（文
献）には、ネックダウン部の径を測定して、延伸後の
プリフォームの外径を制御する光ファイバ用プリフォー
ムの延伸方法において、延伸後のプリフォームのネック
ダウン部長さを延伸前のプリフォーム外径の３倍以上と
してネックダウン部の断面テーパ形状のテーパの傾斜を
緩やかにすることにより、ネックダウン部の径の測定誤
差を小さくして延伸体の最終外径寸法精度を上げる方法
が提案されている。Japanese Patent Application Laid-Open No. 6-127996 (literature) discloses a method of stretching an optical fiber preform in which the diameter of a neck-down portion is measured and the outer diameter of the preform after stretching is controlled. By making the length of the neck-down portion of the subsequent preform at least three times the outer diameter of the preform before stretching and making the slope of the taper of the cross-sectional taper of the neck-down portion gentle, the measurement error of the diameter of the neck-down portion is reduced. There has been proposed a method for increasing the dimensional accuracy of the final outer diameter of the stretched body by using the method.
【０００６】[0006]
【発明が解決しようとする課題】文献の技術を、電気
炉を加熱源とする延伸に適用して外径制御の応答時間を
短くするために引落部の外径測定値により外径制御する
と、仕上がり外径の精度が悪化するという問題があっ
た。その理由としては次のように考えられる。仕上がり
外径の精度を向上させるためには、外径制御に用いる外
径測定器を仕上がり外径に近い部分に設置する必要があ
る。しかし、一方で仕上がり外径に近い部分で外径制御
を行うと、応答時間が長くなり所定の外径に制御するこ
とが困難になる。すなわち、所定の外径に制御しようと
してチャック速度等を変化させた場合は、加熱源に近い
ほど温度が高いためガラス粘度が小さく、外径が大きく
変化するのに対し、加熱源から離れた部分はガラス粘度
が高いために外径の変化量は少ない。加熱源から離れた
部分の外径が大きく変化するのは、加熱源に近い部分が
引き取りチャックの移動により次第に移動してきてから
になるため、チャック速度等が変化した時点からしばら
く時間が経過してからになる。引落部の形状はテーパ状
になっていて、仕上がり外径に近くなるほど加熱源から
離れることになることから、仕上がり外径に近い部分で
外径制御を行なうほど、制御の応答が遅いことになる。When the technique of the literature is applied to stretching using an electric furnace as a heating source and the outer diameter is controlled by a measured outer diameter of a drawn part in order to shorten the response time of the outer diameter control, There is a problem that the accuracy of the finished outer diameter is deteriorated. The reason is considered as follows. In order to improve the accuracy of the finished outer diameter, it is necessary to install an outer diameter measuring device used for controlling the outer diameter at a portion close to the finished outer diameter. However, on the other hand, if the outer diameter control is performed in a portion close to the finished outer diameter, the response time becomes longer and it becomes difficult to control the outer diameter to a predetermined outer diameter. That is, when the chuck speed or the like is changed in order to control the outer diameter to a predetermined value, the temperature is higher as the temperature is closer to the heating source, so that the glass viscosity is smaller and the outer diameter is largely changed. Has a small change in outer diameter because of high glass viscosity. The outer diameter of the part far from the heating source changes largely because the part close to the heating source gradually moves due to the movement of the take-off chuck, so it takes a while after the time when the chuck speed or the like changes. From. The shape of the drawn-down portion is tapered, and the closer to the finished outer diameter, the farther from the heating source, the slower the outer diameter control is at a portion closer to the finished outer diameter, the slower the response of the control will be. .
【０００７】加熱源がバーナ火炎による場合は、加熱範
囲が短いために引落部の長さも短くなるので、加熱源か
らあまり離さずにかつ仕上がり外径に近い外径のところ
で外径制御を行なうことが可能であった。しかし、加熱
源が電気炉の場合は、バーナ加熱の場合と比較すると加
熱範囲が広くなってしまうことから引落部の長さを短く
することが難しいため、バーナ加熱の場合と同程度の外
径精度を得ようとして外径測定を仕上がり外径に近い部
分とすると、加熱源と測定器の間隔が大きくなり、外径
制御の応答時間が長くなってしまい安定な制御ができな
い問題があった。When the heating source is a burner flame, the length of the drawn portion is short because the heating range is short. Therefore, it is necessary to control the outside diameter at an outside diameter close to the finished outside diameter without leaving the heating source too much. Was possible. However, when the heating source is an electric furnace, it is difficult to reduce the length of the drawn-down part because the heating range is wider than in the case of burner heating. If the measurement of the outer diameter is made close to the finished outer diameter in order to obtain accuracy, the distance between the heating source and the measuring instrument becomes larger, and the response time of the outer diameter control becomes longer, so that stable control cannot be performed.
【０００８】また、文献の技術においては、ネックダ
ウン部の長さが長い場合、外径測定器を仕上がり外径に
近い部分に設置することができず、結果的に仕上がり外
径の精度が悪化する問題があった。これはネックダウン
部が長い状態で、仕上がり外径に近い部分の外径を測定
しようとすると、やはり加熱源と外径測定位置の間隔が
大きくなり、外径制御の応答時間が長くなって所定の外
径に調整することが困難となるからである。In the technique of the literature, when the length of the neck-down portion is long, the outer diameter measuring device cannot be installed at a portion close to the finished outer diameter, and as a result, the accuracy of the finished outer diameter is deteriorated. There was a problem to do. This is because when the neck-down part is long, when trying to measure the outer diameter of the part close to the finished outer diameter, the interval between the heating source and the outer diameter measurement position also increases, and the response time of the outer diameter control becomes longer. This is because it becomes difficult to adjust the outer diameter to the above.
【０００９】以上のような現状に鑑み、本発明は従来技
術の問題点を解消し、外径精度の向上した光ファイバ用
ガラス母材を延伸できる方法を提供することを目的とし
ている。In view of the above situation, an object of the present invention is to solve the problems of the prior art and to provide a method for drawing a glass preform for an optical fiber having improved outer diameter accuracy.
【００１０】[0010]
【課題を解決するための手段】上記課題を解決する本発
明は、(1)光ファイバ用ガラス母材の端部より順次加熱
軟化させて外径を縮径する際、引落部の外径がテーパ状
に変化している部分の外径を外径測定器により測定し、
該外径測定値が予め設定した外径値と一致するように制
御しながら延伸する方法において、該外径測定値をｄと
し外径設定値をＤとするとき、ｄ−Ｄ＞０の場合には加
熱源を引き取り方向に、ｄ−Ｄ＜０の場合には加熱源を
引き取り方向とは反対方向にそれぞれ移動させ、且つ外
径測定器と加熱源の間隔は常に一定に保っておくことを
特徴とする光ファイバ用母材の延伸方法、(2)前記外径
測定値ｄと外径設定値Ｄの差（ｄ−Ｄ）に応じて、光フ
ァイバ用ガラス母材の送り込み速度も制御することを特
徴とする上記(1) 記載の光ファイバ用母材の延伸方法、
(3)光ファイバ用ガラス母材の端部より順次加熱軟化さ
せて外径を縮径する際、引落部の外径がテーパ状に変化
している部分の外径を外径測定器により測定し、該外径
測定値が予め設定した外径値と一致するように制御しな
がら延伸する方法において、該外径測定値をｄとし外径
設定値をＤとするとき、ｄ−Ｄ＞０の場合には光ファイ
バ母材の送り込み速度と延伸体の引き取り速度を同時に
減少させ、ｄ−Ｄ＜０の場合には光ファイバ母材の送り
込み速度と延伸体の引き取り速度を同時に増加させ、且
つ外径測定器と加熱源の間隔は常に一定に保っておくこ
とを特徴とする光ファイバ用母材の延伸方法、および
(4)前記外径測定値ｄと外径設定値Ｄの差（ｄ−Ｄ）に
応じた送り込み速度の変化量が、引き取り速度の変化量
より大きいことを特徴とする上記(3) 記載の光ファイバ
用母材の延伸方法、である。SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems is as follows: (1) When the outer diameter of the drawn-down portion is reduced when the outer diameter is reduced by sequentially heating and softening from the end of the glass base material for optical fiber. Measure the outer diameter of the part that changes in a tapered shape with an outer diameter measuring device,
In the method of stretching while controlling the measured outer diameter value to be equal to the preset outer diameter value, when the outer diameter measured value is d and the outer diameter set value is D, d−D> 0 In the case of d-D <0, move the heating source in the direction opposite to the direction in which the heating source is moved, and keep the distance between the outer diameter measuring device and the heating source constant at all times. (2) controlling the feeding speed of the glass preform for optical fiber according to the difference (d−D) between the measured outer diameter d and the set outer diameter D (d). The method of stretching the optical fiber preform according to the above (1), wherein
(3) When reducing the outer diameter by sequentially heating and softening from the end of the glass base material for optical fiber, measure the outer diameter of the part where the outer diameter of the drawn part changes in a tapered shape with an outer diameter measuring device In the method of stretching while controlling the measured outer diameter value to be equal to a preset outer diameter value, when the outer diameter measured value is d and the outer diameter set value is D, d−D> 0 In the case of, the feeding speed of the optical fiber preform and the drawing speed of the stretched body are simultaneously reduced, and if d−D <0, the feeding speed of the optical fiber preform and the drawing speed of the stretched body are simultaneously increased, and The method of stretching the optical fiber preform, characterized in that the distance between the outer diameter measuring device and the heating source is always kept constant, and
(4) The amount of change in the feeding speed according to the difference (d−D) between the measured outer diameter d and the set outer diameter D is larger than the change in the take-off speed. A method for stretching a preform for an optical fiber.
【００１１】仕上がり径の精度を上げるためには、引落
部のうち外径測定器による測定位置をより仕上がり外径
に近い部分とする必要がある。しかし、仕上がり外径に
近い位置による外径制御は、加熱部と外径測定部の間隔
が離れるので応答時間が遅くなり、外径制御により所定
の外径に調整することが困難になる問題があった。本発
明者らは、上記課題を解決するために、測定外径と予め
設定した外径との差に応じて加熱源を上下に移動するこ
と、このとき加熱源と外径測定部の距離は常に一定に保
持しておくことを考えついた。In order to improve the accuracy of the finished diameter, it is necessary to make the position of the drawn-out portion measured by the outer diameter measuring device closer to the finished outer diameter. However, the control of the outer diameter at a position close to the finished outer diameter has a problem that the interval between the heating unit and the outer diameter measuring unit is long, so that the response time is slow, and it is difficult to adjust the outer diameter to a predetermined outer diameter by the outer diameter control. there were. The present inventors, in order to solve the above problems, to move the heating source up and down according to the difference between the measured outer diameter and a preset outer diameter, at this time the distance between the heating source and the outer diameter measuring unit is I always wanted to keep it constant.
【００１２】本発明に到達した経緯から説明する。すな
わち、従来の外径制御方法は、測定外径と設定外径との
差に応じて延伸体の引き取り速度を制御するもので、測
定外径が設定外径より大きくなった時は引取速度を増加
させ、逆に測定外径が設定外径より小さくなったときに
は引き取り速度を減少させる方法であった。この方法で
は、例えば、測定外径が大きくなって引き取り速度を増
加させるとこれに伴って引落部の長さが長くなってしま
い、その過程で引落部の下部は位置が下がることにな
る。引落部はテーパ状になっているので、図４の(a) の
状態から(c) の破線に示すように引落部が下がった状態
となると、引き取り速度増加によって現実には縮径して
いるのに、外径測定値では外径が増加していることにな
り、外径制御の応答が遅くなるものと考えられる。ま
た、図４の(b) の破線で示すように引落部が上方に移動
した状態では、現実には増径しているのに外径測定値は
やはり対応が遅れることがわかる。A description will be given of how the present invention has been achieved. That is, the conventional outer diameter control method controls the take-up speed of the stretched body in accordance with the difference between the measured outer diameter and the set outer diameter.When the measured outer diameter becomes larger than the set outer diameter, the take-up speed is increased. In this method, when the measured outer diameter is smaller than the set outer diameter, the take-off speed is decreased. In this method, for example, when the take-out speed is increased due to an increase in the measured outer diameter, the length of the drawn-down portion is correspondingly increased, and the lower part of the drawn-down portion is lowered in the process. Since the withdrawn portion is tapered, when the withdrawn portion is lowered from the state shown in FIG. 4A to the broken line in FIG. 4C, the diameter is actually reduced by the increase in the take-up speed. However, it is considered that the outer diameter is increased in the measured outer diameter, and the response of the outer diameter control is slowed. Also, in the state where the withdrawn portion moves upward as shown by the broken line in FIG. 4B, it can be seen that the measured value of the outer diameter is still delayed even though the diameter actually increases.
【００１３】上記のような考察から、本発明の第一の方
法は、仕上がり外径に近い部分、より具体的には引落部
のテーパが終わり一定径の延伸体となる部分に近い部分
で外径測定し、しかも外径制御の応答時間をより短くす
るために、外径測定値をｄとし、外径設定値をＤとする
ときの両者の差（ｄ−Ｄ）に応じて加熱源そのものを上
下に移動させるものである。その際、加熱源と外径測定
器との間隔は一定に保ったまま移動させる。すなわち、
外径測定値ｄが外径設定値Ｄより大きい場合（ｄ−Ｄ＞
０）は加熱源を下降させて縮径が進んだ部分をさらに加
熱縮径させることで仕上がり外径を小さくし、逆に外径
測定値が外径設定値Ｄより小さい場合（ｄ−Ｄ＜０）は
加熱源を上昇させて、縮径が進んだ部分から加熱源を遠
ざけ、縮径を停止させることで仕上がり外径を大きくす
る。加熱源の移動により前記仕上がり外径変化に加え
て、テーパ部の外径を測定している外径測定器も同時に
移動するので、外径測定値への応答は敏感になる。From the above considerations, the first method of the present invention provides a method in which the outer diameter is approximated at a portion close to the finished outer diameter, more specifically, at a portion close to a portion where the tapered portion of the drawn down portion ends to become a stretched body having a constant diameter. In order to measure the diameter and further shorten the response time of the outer diameter control, the heating source itself is determined in accordance with the difference (d-D) between the measured outer diameter as d and the set outer diameter as D. Is moved up and down. At this time, the heating source and the outer diameter measuring device are moved while being kept constant. That is,
When the measured outer diameter d is larger than the set outer diameter D (d−D>
0) is to reduce the finished outer diameter by lowering the heating source to further reduce the diameter of the portion whose diameter has been advanced, and conversely, when the measured outer diameter is smaller than the outer diameter set value D (d−D < 0) raises the heating source, moves the heating source away from the part where the diameter reduction has progressed, and stops the diameter reduction to increase the finished outer diameter. In addition to the change in the finished outer diameter, the outer diameter measuring device that measures the outer diameter of the tapered portion also moves by the movement of the heating source, so that the response to the outer diameter measured value becomes more sensitive.
【００１４】なお、ネックダウン部は「加熱源によって
加熱され温度が最も高くなって外径が急激に変化してい
る部分」と「温度が下がりつつある領域で外径の変化量
が次第に小さくなっていく部分」の二つに分けて考えら
れ、後者の部分を「縮径が進んだ部分」という。従って
本願発明における「縮径が進んだ部分」には、加熱源領
域を通過した直後の領域から外径が一定になる直前の領
域までを含む。The neck-down portion includes "a portion where the outer diameter is rapidly changed due to being heated by the heating source and having the highest temperature" and "a portion where the outer diameter changes gradually in a region where the temperature is decreasing." The latter part is called the "part with reduced diameter". Therefore, the “portion in which the diameter is reduced” in the present invention includes a region immediately after passing through the heating source region to a region immediately before the outer diameter becomes constant.
【００１５】また、加熱源への母材の送り込み速度を、
外径測定値ｄと外径設定値Ｄの差に応じて制御する方法
も採用できる。この場合、外径測定値ｄが外径設定値Ｄ
より大きくなったとき（ｄ−Ｄ＞０）には、送り込み速
度を減少させ、逆に小さくなったとき（ｄ−Ｄ＜０）に
は、送り込み速度を増加させるように制御する。このよ
うにすると、例えば測定外径が太くなった場合、送り込
み速度が減少するので引落部が上部に長くなると考えら
れる。したがって、引落部下部の外径測定部のテーパ部
は上下に殆ど動かないため、送り込み速度変化による縮
径効果がそのまま外径測定値に現れる。よって引き取り
速度を制御する方法より送り込み速度を制御する方法の
ほうが応答時間は短い。The feeding speed of the base material to the heating source is
A method of controlling according to the difference between the measured outer diameter d and the set outer diameter D can also be employed. In this case, the measured outer diameter d is equal to the set outer diameter D.
When it becomes larger (d−D> 0), the feeding speed is reduced, and when it becomes smaller (d−D <0), the feeding speed is increased. In this case, for example, when the measured outer diameter is increased, the feeding speed is reduced, and the drawn-down portion is considered to be longer at the upper portion. Therefore, since the tapered portion of the outer diameter measuring portion below the pulling portion hardly moves up and down, the diameter reducing effect due to the change in the feeding speed appears in the outer diameter measured value as it is. Therefore, the response time is shorter in the method of controlling the feeding speed than in the method of controlling the take-up speed.
【００１６】図１は本発明の一実施態様を示す概略図で
あり、図１において、光ファイバ用母材３はその上下端
に取り付けたダミー棒２，７を介して、送り込み用チャ
ック１および引き取り用チャック８に把持され、加熱炉
４中に保持されている。加熱炉４のヒータ５の下部に
は、引落部１７の外径を測定するために外径測定器１６
が設けてあり、引落部の下部で延伸体６の仕上がり径に
近い部分を測定できるようにしてある。また、加熱炉４
は炉体移動用ボールねじ１３で炉体移動用モータ１１に
より上下方向に移動可能である。送り込み用チャックは
送り込み用チャック移動用ボールねじ９に取り付けられ
送り込み用チャック移動用モータにより上下方向に移動
可能である。また、引き取り用チャック８も引き取り用
チャック移動用ボールねじ１５に取り付けられ引き取り
用チャック移動用モータ１４により上下方向に移動可能
である。本発明においては、外径測定器からの測定信号
は制御装置１２に送られ、ここで演算された外径設定値
とのずれに応じた制御信号を炉体移動用モータ１１に送
り、加熱炉４を移動させる。移動のさせ方はすでに述べ
たとおりである。さらに制御装置１２の制御信号に応じ
て送り込み用チャック移動用モータ１０および／または
引き取り用チャック移動用モータ１４の速度を制御でき
る。FIG. 1 is a schematic view showing an embodiment of the present invention. In FIG. 1, a preform 3 for an optical fiber has a feed chuck 1 and a feed chuck 1 through dummy rods 2 and 7 attached to upper and lower ends thereof. It is gripped by a pick-up chuck 8 and held in the heating furnace 4. Below the heater 5 of the heating furnace 4, an outer diameter measuring device 16 for measuring the outer diameter of the withdrawn portion 17 is provided.
Is provided so that a portion close to the finished diameter of the stretched body 6 can be measured below the drawn-down portion. In addition, heating furnace 4
Is a ball screw 13 for moving the furnace body and can be moved vertically by a motor 11 for moving the furnace body. The feeding chuck is attached to the feeding chuck moving ball screw 9 and is vertically movable by a feeding chuck moving motor. The picking chuck 8 is also attached to the picking chuck moving ball screw 15 and can be moved up and down by the picking chuck moving motor 14. In the present invention, a measurement signal from the outer diameter measuring device is sent to the control device 12, and a control signal corresponding to a deviation from the outer diameter set value calculated here is sent to the furnace body moving motor 11, and the heating furnace Move 4. The method of moving is as described above. Further, the speed of the feed chuck moving motor 10 and / or the pick-up chuck moving motor 14 can be controlled according to the control signal of the control device 12.
【００１７】以上述べてきたように、本発明によれば従
来より外径制御における応答を敏感にすることができる
ので、外径測定器を加熱源から離れた位置に設置しても
十分安定な外径制御が可能になる。従って、外径測定器
を仕上がり外径に近い部分に設置することができ、結果
的に外径が高精度の延伸体を得ることができる。なお本
発明は、従来技術では外径測定器を仕上がり外径に近い
部分に設置できなかった、例えば加熱源が電気炉で引落
部の長さが長くなってしまうような場合に適用すると特
に有利な効果があるが、加熱源がバーナであっても適用
可能である。また縦型と横型のいずれの延伸装置にも適
用できる。さらに、本発明は従来の制御方法に組み合わ
せても適用可能である。すなわち、外径測定値ｄと外径
設定値Ｄの差に応じて、母材の送り込み速度を制御する
と同時に炉体の移動も制御してもよい。または、測定外
径と設定外径の差に応じて、引き取り速度を制御すると
同時に炉体の移動も制御してもよい。ただし、上述のよ
うに、引き取り速度の制御の組み合わせるよりは送り込
み速度の制御と組み合わせるほうが外径制御の応答が敏
感である点でより望ましい。As described above, according to the present invention, the response in the outer diameter control can be made more sensitive than before, so that even if the outer diameter measuring device is installed at a position away from the heating source, it is sufficiently stable. Outer diameter control becomes possible. Therefore, the outer diameter measuring device can be installed at a portion close to the finished outer diameter, and as a result, a stretched body having a highly accurate outer diameter can be obtained. In addition, the present invention is particularly advantageous when applied to a case where the outer diameter measuring device cannot be installed in a portion close to the finished outer diameter in the prior art, for example, in a case where the length of the drawn-down portion becomes long in a heating source in an electric furnace. However, the present invention is applicable even if the heating source is a burner. Further, the present invention can be applied to both vertical and horizontal stretching apparatuses. Further, the present invention is applicable even when combined with a conventional control method. That is, according to the difference between the measured outer diameter value d and the set outer diameter value D, the movement of the furnace body may be controlled simultaneously with controlling the feeding speed of the base material. Alternatively, according to the difference between the measured outer diameter and the set outer diameter, the movement of the furnace body may be controlled at the same time as the take-off speed is controlled. However, as described above, it is more desirable to combine with the control of the feeding speed than the combination of the control of the take-up speed in that the response of the outer diameter control is sensitive.
【００１８】以上述べてきたように、外径測定値により
加熱源の移動を制御する本発明の延伸方法は、従来困難
であった仕上がり外径に近い部分での外径測定とその結
果得られた外径測定値による制御性の両立を可能にする
ものであるが、加熱源が電気炉の場合は大型になるため
移動が困難になる場合がある。そのような場合、本発明
の第二の方法によれば、加熱源（炉体）は停止のままで
且つ加熱源と引落部外径測定器との間隔も一定のまま
で、送り込み速度と引き取り速度を同時に増加または同
時に減少させることで、引落部外径測定位置と加熱源の
相対的な位置関係を、前記した炉体移動の場合と等価に
できるため、同様の効果を得ることができる。As described above, the stretching method of the present invention, in which the movement of the heating source is controlled by the measured outer diameter value, measures the outer diameter at a portion close to the finished outer diameter, which has been conventionally difficult, and obtains the result. Although it is possible to achieve both controllability based on the measured outer diameter, when the heating source is an electric furnace, it may be difficult to move due to the large size of the heating source. In such a case, according to the second method of the present invention, while the heating source (furnace body) is stopped and the distance between the heating source and the pull-out portion outer diameter measuring device is also kept constant, the feeding speed and the take-off are taken. By simultaneously increasing or decreasing the speed, the relative positional relationship between the pull-out portion outer diameter measurement position and the heating source can be equivalent to the case of the furnace body movement described above, and the same effect can be obtained.
【００１９】すなわち、外径測定値が外径設定値より大
きくなった場合、送り込み速度と引き取り速度を同時に
減少させ、外径測定値が外径設定値より小さくなった場
合、送り込み速度と引き取り速度を同時に増加させる。
このように両速度を同時に変化させることで相対的に炉
体が移動したのと同じ効果を得ることができる。なお、
送り込み速度と引き取り速度の両方を同時に増加または
減少させる際、減少させる量は必ずしも同じ量である必
要はなく、送り込み速度を引き取り速度より大きく変化
させてもよく、逆でもよい。ただし、先に説明した理由
から送り込み速度を引き取り速度より多く変化させるほ
うが望ましい。That is, when the measured outer diameter becomes larger than the set outer diameter, the feeding speed and the take-off speed are simultaneously reduced, and when the measured outer diameter becomes smaller than the set outer diameter, the feeding speed and the pick-up speed are reduced. At the same time.
As described above, by simultaneously changing both speeds, the same effect as the relative movement of the furnace body can be obtained. In addition,
When simultaneously increasing or decreasing both the feed speed and the take-up speed, the amount of decrease is not necessarily the same, and the feed speed may be changed to be larger than the take-up speed, or vice versa. However, it is desirable to change the feeding speed more than the take-up speed for the reason explained above.
【００２０】（実施例１）外径８０ｍｍの光フアイバ用
母材（３）を３０ｍｍに延伸するため、鉛直方向に貫通
口を有する加熱炉（４）に母材を挿入し、母材の両端に
それぞれ一体化されたダミー棒（２，７）を介してチャ
ック（１，８）で把持し、母材の下端から上端にかけて
順次加熱軟化させつつ、延伸を行った。その際、引落部
（１７）の一部の外径を外径測定器（１６）で測定し、
得られた測定値をもとに、下記の条件でチャック速度と
炉体速度を制御した。なお、各速度は正の値が下降方向
を示す。 上チャック速度＝（上チャック速度設定値）−K1×（外
径測定値−外径設定値） 下チャック速度＝ 下チャック速度設定値 炉体移動速度＝K3×（外径測定値−外径設定値） 上チャック速度設定値＝１０ｍｍ／分 下チャック速度設定値＝７１ｍｍ／分 K1 ＝２０分-1 K3 ＝ ５分-1 外径設定値＝３０．５ｍｍ 上記条件で延伸を実施した結果、得られた（６）の外径
は３０．０±０．１ｍｍと良好で、図１のグラフに示す
ように延伸中の外径測定値は設定値とほぼ一致してい
た。Example 1 In order to stretch an optical fiber base material (3) having an outer diameter of 80 mm to 30 mm, the base material was inserted into a heating furnace (4) having a through hole in the vertical direction, and both ends of the base material were inserted. Each of the base materials was gripped by chucks (1, 8) via dummy rods (2, 7) integrated with the base material, and stretched while being sequentially heated and softened from the lower end to the upper end of the base material. At that time, the outer diameter of a part of the withdrawn portion (17) is measured with an outer diameter measuring device (16),
On the basis of the obtained measured values, the chuck speed and the furnace body speed were controlled under the following conditions. Each speed has a positive value indicating a descending direction. Upper chuck rate = (upper chuck speed setpoint) -K 1 × (outer size measurements - outer axis length set value) lower chuck rate = lower chuck speed setpoint furnace body moving speed = K 3 × (outer size measurements - outer implementing the stretched axis length set value) upper chuck speed setpoint = 10 mm / min lower chuck speed setting = 71 mm / min K 1 = 20 min -1 K 3 = 5 min -1 outer axis length set value = 30.5 mm above conditions As a result, the obtained outer diameter of (6) was as good as 30.0 ± 0.1 mm, and as shown in the graph of FIG. 1, the measured outer diameter during stretching almost coincided with the set value.
【００２１】（実施例２）外径８０ｍｍの光フアイバ用
母材（３）を３０ｍｍに延伸するため、鉛直方向に貫通
口を有する加熱炉（４）に母材を挿入し、母材の両端に
それぞれ一体化されたダミー棒（２，７）を介してチャ
ック（１，８）で把持し、母材の下端から上端にかけて
順次加熱軟化させつつ、延伸を行った。その際、引落部
（１７）の一部の外径を外径測定器（１６）で測定し、
得られた測定値をもとに、炉体（４）を固定して下記の
条件でチャック速度を制御した。なお、各速度は正の値
が下降方向を示す。 上チャック速度＝（上チャック速度設定値）−K1×（外
径測定値−外径設定値） 下チャック速度＝（下チャック速度設定値）−K2×（外
径測定値−外径設定値） 上チャック速度設定値＝１０ｍｍ／分 下チャック速度設定値＝７１ｍｍ／分 K1 ＝２０分-1 K2 ＝１０分-1 外径設定値＝３０．５ｍｍ 上記条件で延伸を実施した結果、得られた（６）の外径
は３０．０±０．１ｍｍと良好であった。(Example 2) In order to stretch an optical fiber base material (3) having an outer diameter of 80 mm to 30 mm, the base material was inserted into a heating furnace (4) having a through hole in the vertical direction, and both ends of the base material were inserted. Each of the base materials was gripped by chucks (1, 8) via dummy rods (2, 7) integrated with the base material, and stretched while being sequentially heated and softened from the lower end to the upper end of the base material. At that time, the outer diameter of a part of the withdrawn portion (17) is measured with an outer diameter measuring device (16),
Based on the obtained measured values, the furnace body (4) was fixed and the chuck speed was controlled under the following conditions. Each speed has a positive value indicating a descending direction. Upper chuck rate = (upper chuck speed setpoint) -K 1 × (outer size measurements - outer axis length set value) lower chuck speed = (lower chuck speed setpoint) -K 2 × (outer size measurements - outer diameter set value) upper chuck speed setpoint = 10 mm / min lower chuck speed setting = 71 mm / min K 1 = 20 min -1 K 2 = 10 min -1 outer axis length set value = 30.5 mm result of the stretching under the above conditions The outer diameter of the obtained (6) was as good as 30.0 ± 0.1 mm.
【００２２】（実施例３）外径８０ｍｍの光フアイバ用
母材（３）を３０ｍｍに延伸するため、鉛直方向に貫通
口を有する加熱炉（４）に母材を挿入し、母材の両端に
それぞれ一体化されたダミー棒（２，７）を介してチャ
ック（１，８）で把持し、母材の下端から上端にかけて
順次加熱軟化させつつ、延伸を行った。その際、引落部
（１７）の一部の外径を外径測定器（１６）で測定し、
得られた測定値をもとに、下記の条件でチャック速度と
炉体速度を制御した。なお、各速度は正の値が下降方向
を示す。 上チャック速度＝１０ｍｍ／分 下チャック速度＝７１ｍｍ／分 炉体移動速度＝K3×（外径測定値−外径設定値） K3 ＝５０分-1 外径設定値＝３０．５ｍｍ 上記条件で延伸を実施した結果、得られた（６）の外径
は３０．０±０．１ｍｍと良好で、図１のグラフに示す
ように延伸中の外径測定値は設定値とほぼ一致してい
た。Example 3 In order to stretch an optical fiber base material (3) having an outer diameter of 80 mm to 30 mm, the base material was inserted into a heating furnace (4) having a through hole in a vertical direction, and both ends of the base material were inserted. Each of the base materials was gripped by chucks (1, 8) via dummy rods (2, 7) integrated with the base material, and stretched while being sequentially heated and softened from the lower end to the upper end of the base material. At that time, the outer diameter of a part of the withdrawn portion (17) is measured with an outer diameter measuring device (16),
On the basis of the obtained measured values, the chuck speed and the furnace body speed were controlled under the following conditions. Each speed has a positive value indicating a descending direction. Upper chuck speed = 10 mm / min lower chuck speed = 71 mm / min furnace body moving speed = K 3 × (outer size measurements - outer axis length set value) K 3 = 50 min -1 outer axis length set value = 30.5 mm above conditions As a result, the outer diameter of the obtained (6) was as good as 30.0 ± 0.1 mm, and as shown in the graph of FIG. 1, the measured outer diameter during the stretching almost coincided with the set value. I was
【００２３】（比較例）上記実施例 の条件を下記の条
件に変え、同様の延伸を行ったところ、得られた延伸体
の外径は３０．０±３．０ｍｍと外径が不安定な結果と
なった。また、延伸中の外径測定値は図３に示したよう
に外径設定値と一致せず、不安定な状態であった。 上チャック速度＝ 上チャック速度設定値 下チャック速度＝（下チャック速度設定値）＋K2×（外
径測定値−外径設定値） 上チャック速度設定値＝１０ｍｍ／分 下チャック速度設定値＝７１ｍｍ／分 K2 ＝１０分-1 外径設定値＝３０．５ｍｍ(Comparative Example) When the same stretching was performed by changing the conditions of the above example to the following conditions, the outer diameter of the obtained stretched body was 30.0 ± 3.0 mm, and the outer diameter was unstable. The result was. Further, the measured outer diameter during stretching did not match the set outer diameter as shown in FIG. 3 and was in an unstable state. Upper chuck speed = upper chuck speed setting value under the chuck speed = (lower chuck speed setting value) + K 2 × (outer size measurements - outer axis length set value) upper chuck speed setpoint = 10 mm / min lower chuck speed setting = 71 mm / Min K 2 = 10 min- 1 Outer diameter set value = 30.5 mm
【００２４】[0024]
【発明の効果】以上説明したように、本発明によれば延
伸体の設定値からのずれへの応答を従来より敏速に、し
かも適切に対応して加熱延伸できるので、得られる光フ
ァイバ用ガラス母材の寸法精度の向上に大いに有効であ
る。As described above, according to the present invention, the response to the deviation from the set value of the stretched body can be heated and stretched more promptly and more appropriately than in the prior art. It is very effective for improving the dimensional accuracy of the base material.
【図１】 本発明の一実施態様を説明する概略図であ
る。FIG. 1 is a schematic diagram illustrating an embodiment of the present invention.
【図２】 本発明の実施例における外径設定値と外径測
定値のデータを示すグラフである。FIG. 2 is a graph showing data of an outer diameter set value and an outer diameter measured value in an example of the present invention.
【図３】 本発明の比較例における外径設定値と外径測
定値のデータを示すグラフである。FIG. 3 is a graph showing data of an outer diameter set value and an outer diameter measured value in a comparative example of the present invention.
【図４】 引落部の移動状態による外径測定値のずれを
説明する図であり、縦軸は外径（ｍｍ）、横軸は時間
（分）を表す。FIG. 4 is a diagram for explaining a deviation of an outer diameter measurement value according to a moving state of a withdrawn part, wherein a vertical axis represents an outer diameter (mm), and a horizontal axis represents time (minute).
【図５】 従来の延伸方法を説明する概略図である。FIG. 5 is a schematic diagram illustrating a conventional stretching method.
【図６】 従来の延伸方法を説明する概略図である。FIG. 6 is a schematic diagram illustrating a conventional stretching method.
１ 送り込み用チャック、 ２ ダミー棒、 ３
光ファイバ用母材、４ 加熱炉、 ５
ヒータ、 ６ 延伸体、７ ダミー棒、
８ 引き取り用チャック、９ 送り込み用チャ
ック移動用ボールねじ、１０ 送り込み用チャック移動
用モータ、１１ 炉体移動用モータ、 １２ 制御装
置、１３ 炉体移動用ボールねじ、１４ 引き取り用チ
ャック移動用モータ、１５ 引き取り用チャック移動用
ボールねじ、１６ 外径測定器、 １７ 引落
部。1 chuck for feeding, 2 dummy bar, 3
Preform for optical fiber, 4 heating furnace, 5
Heater, 6 stretched body, 7 dummy bar,
Reference Signs List 8 pick-up chuck, 9 feed chuck moving ball screw, 10 feed chuck moving motor, 11 furnace body moving motor, 12 controller, 13 furnace body moving ball screw, 14 pick-up chuck moving motor, 15 Ball screw for pick-up chuck movement, 16 outer diameter measuring instrument, 17 drop-down part.
Claims (4)
加熱軟化させて外径を縮径する際、引落部の外径がテー
パ状に変化している部分の外径を外径測定器により測定
し、該外径測定値が予め設定した外径値と一致するよう
に制御しながら延伸する方法において、該外径測定値を
ｄとし外径設定値をＤとするとき、ｄ−Ｄ＞０の場合に
は加熱源を引き取り方向に、ｄ−Ｄ＜０の場合には加熱
源を引き取り方向とは反対方向にそれぞれ移動させ、且
つ外径測定器と加熱源の間隔は常に一定に保っておくこ
とを特徴とする光ファイバ用母材の延伸方法。1. An outer diameter measuring device for reducing the outer diameter of an optical fiber glass preform by sequentially heating and softening the end from an end thereof, wherein the outer diameter of a drawn-down portion is tapered. In the method of stretching while controlling the measured outer diameter to match the preset outer diameter value, when the measured outer diameter is d and the set outer diameter is D, d−D If> 0, the heating source is moved in the take-off direction; if d−D <0, the heating source is moved in the direction opposite to the take-off direction, and the distance between the outer diameter measuring device and the heat source is always constant. A method of stretching a preform for an optical fiber, characterized in that the preform is kept.
（ｄ−Ｄ）に応じて、光ファイバ用ガラス母材の送り込
み速度も制御することを特徴とする請求項１記載の光フ
ァイバ用母材の延伸方法。2. The feeding speed of the glass preform for an optical fiber is controlled according to a difference (d−D) between the measured outer diameter value d and the set outer diameter value D. A method for stretching a preform for an optical fiber.
加熱軟化させて外径を縮径する際、引落部の外径がテー
パ状に変化している部分の外径を外径測定器により測定
し、該外径測定値が予め設定した外径値と一致するよう
に制御しながら延伸する方法において、該外径測定値を
ｄとし外径設定値をＤとするとき、ｄ−Ｄ＞０の場合に
は光ファイバ母材の送り込み速度と延伸体の引き取り速
度を同時に減少させ、ｄ−Ｄ＜０の場合には光ファイバ
母材の送り込み速度と延伸体の引き取り速度を同時に増
加させ、且つ外径測定器と加熱源の間隔は常に一定に保
っておくことを特徴とする光ファイバ用母材の延伸方
法。3. When the outer diameter of the glass base material for an optical fiber is gradually reduced by heating and softening sequentially from the end portion, the outer diameter of the portion where the outer diameter of the drawn-down portion changes in a tapered shape is measured with an outer diameter measuring device. In the method of stretching while controlling the measured outer diameter to match the preset outer diameter value, when the measured outer diameter is d and the set outer diameter is D, d−D If> 0, the feeding speed of the optical fiber preform and the drawing speed of the drawn body are simultaneously reduced, and if d−D <0, the feeding speed of the optical fiber preform and the drawing speed of the drawn body are simultaneously increased. And a method of stretching a preform for an optical fiber, wherein the distance between the outer diameter measuring device and the heating source is always kept constant.
−Ｄ）に応じた送り込み速度の変化量が、引き取り速度
の変化量より大きいことを特徴とする請求項３記載の光
ファイバ用母材の延伸方法。4. The difference (d) between the measured outer diameter d and the set outer diameter D.
4. The method of drawing an optical fiber preform according to claim 3, wherein a change amount of the feeding speed according to -D) is larger than a change amount of the take-up speed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34540998A JP2000169171A (en) | 1998-12-04 | 1998-12-04 | Method for drawing optical fiber preform |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP34540998A JP2000169171A (en) | 1998-12-04 | 1998-12-04 | Method for drawing optical fiber preform |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000169171A true JP2000169171A (en) | 2000-06-20 |
Family
ID=18376409
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP34540998A Pending JP2000169171A (en) | 1998-12-04 | 1998-12-04 | Method for drawing optical fiber preform |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000169171A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1559691A1 (en) * | 2002-06-19 | 2005-08-03 | Sumitomo Electric Industries, Ltd. | Method for drawing glass parent material and drawing machine for use therein |
| CN111153589A (en) * | 2020-03-18 | 2020-05-15 | 上海昱品通信科技股份有限公司 | Traction equipment for extending special optical fiber preform and drawing capillary tube |
-
1998
- 1998-12-04 JP JP34540998A patent/JP2000169171A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1559691A1 (en) * | 2002-06-19 | 2005-08-03 | Sumitomo Electric Industries, Ltd. | Method for drawing glass parent material and drawing machine for use therein |
| EP1559691A4 (en) * | 2002-06-19 | 2006-03-01 | Sumitomo Electric Industries | Method for drawing glass parent material and drawing machine for use therein |
| US7886561B2 (en) | 2002-06-19 | 2011-02-15 | Sumitomo Electric Industries, Ltd. | Method for drawing glass parent material and drawing machine for use therein |
| CN111153589A (en) * | 2020-03-18 | 2020-05-15 | 上海昱品通信科技股份有限公司 | Traction equipment for extending special optical fiber preform and drawing capillary tube |
| CN111153589B (en) * | 2020-03-18 | 2024-02-06 | 上海昱品通信科技股份有限公司 | Traction equipment for extension and capillary drawing of special optical fiber preform |
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