JPH02307840A - Method for spinning optical fiber - Google Patents

Abstract

PURPOSE:To operate a receiving machine almost at its high-limit capacity by detecting the receiving velocity of the receiving machine and controlling the delivery velocity so that the detection value is held at a set velocity. CONSTITUTION:An optical fiber preform 1 is delivered at a low speed by a feeder 2, the tip is heated by a heating furnace 3 and melted, and the preform is spun out into an optical fiber having a specified diameter by the receiving machine 4. The diameter of the optical fiber 5 received by the machine 4 is measured by an outer diameter measuring machine 6 and inputted to a receiving machine controller 7, and the receiving velocity V2 of the machine 4 is increased or decreased so that the diameter of the optical fiber 5 is fixed. In this case, the receiving velocity V2 of the machine 4 is detected, and the detected receiving velocity V2 is fed back to the feeder 2 through a computing element 8. The delivery velocity V1 of the preform 1 is controlled so that the receiving velocity V2 is kept close to the set receiving velocity.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical fiber spinning method.

[Prior Art] A conventional optical fiber spinning method will be explained with reference to FIG. 3. A cylindrical optical fiber preform 1 with an outer diameter of, for example, around 4.0 mm is fed out at a constant speed by a feeding device 2. 1, the tip is heated and melted in a heating furnace 3, collected by a pulling machine 4, and stretched to a predetermined diameter.
In this way, the optical fiber 5 is spun. In order to keep the diameter of the optical fiber to be taken constant, the diameter of the optical fiber 5 is measured by an outer diameter measuring device 6 during the taking, and a taking machine control device 7 performs control based on the measured value. The take-up speed ■2 of the take-up machine 4 is varied. That is, when the measured optical fiber diameter is larger than the target value, the take-up speed (2) is increased, and when it is smaller, it is decreased so that the optical fiber diameter falls within the allowable range.

[Problems to be Solved by the Invention] By the way, the diameter of an optical fiber base material (hereinafter abbreviated as base material) is not usually constant over the entire length of each individual base material, and the diameter varies depending on the position in the length direction, for example, 35 mm. m m
It varies widely, such as in the range of +7 mm to 45 mmφ.

Therefore, in the conventional spinning method described above, in which the feeding speed V1 of the base material 1 is kept constant and the variation in the diameter of the base material 1 is responded to only by the take-up speed V2, the take-up speed V2 becomes large and fluctuates over a wide range. . Therefore, if you try to operate the pulling machine 4 near the upper limit of its capacity, when the diameter of the base material 1 reaches its maximum, it will exceed the capacity (maximum pulling speed) of the pulling machine 4 and keep the optical fiber diameter constant. Conventionally, the take-up machine 4 was used at a location considerably lower than the upper limit of its capacity.

The present invention has been made in order to solve the above problems, and aims to provide an optical fiber spinning method that allows a pulling machine to be operated near the upper limit of its pulling capacity and enables high-speed operation. .

[Means for Solving the Problems] The optical fiber spinning method of the present invention that solves the above problems includes:
The present invention is characterized in that the take-off speed (2) of the take-off machine is detected, and the delivery speed (V) of the optical fiber preform is controlled so that the take-off speed (2) is maintained near the set take-off speed.

[Function] In the spinning method described above, the diameter of the optical fiber is kept constant by varying the take-up speed (2) of the take-off machine in accordance with the measured diameter of the optical fiber. If this take-off speed ■2 is close to the set take-off speed, the feed speed of the optical fiber base material ■1
However, if the take-off speed V2 deviates from the vicinity of the set take-off speed, this take-off speed V2 is fed back to the optical fiber preform delivery device and the optical fiber preform delivery speed Vl is maintained as it is. is done later or earlier,
As a result, the take-off speed V2 required to keep the optical fiber diameter constant is maintained close to the set take-off speed again. In this way, the take-off speed (2) is always maintained close to the set take-off speed, regardless of variations in the optical fiber diameter. Thereby, there is no need to leave a large amount of surplus capacity in the capacity of the taking machine, and it becomes possible to operate the taking machine near the upper limit of its capacity.

[Example] Hereinafter, a first example of the optical fiber spinning method of the present invention will be described.
This will be explained with reference to FIGS.

In FIG. 1, parts common to the conventional one are designated by the same reference numerals. An optical fiber preform 1 is fed out at a low speed of, for example, about 3 mm/min by a feeding device 2, and its tip end is transferred to a heating furnace 3. The optical fiber is heated and melted, and taken out by a pulling machine 4 and stretched thinly into an optical fiber having a predetermined diameter. The diameter of the optical fiber 5 taken up by the take-off machine 4 is measured by an outer diameter measuring device 6, and the measured value is input to the take-off machine control device 7. In this pulling machine control section 7, proportional control, integral control, and differential control are performed based on the diameter of the optical fiber measured by the outer diameter measuring device 6, and the pulling machine 4 is controlled so that the diameter of the optical fiber is constant. Increase/decrease the take-up speed ■2.

The above is the same as the conventional one, but in the present invention, the take-up speed ■2 of the take-up machine 4 is detected, and the detected take-up speed ■2 is fed back to the sending device 2 side via the computing device 8.
The feed-out speed (1) of the base material is controlled so that the take-up speed (2) is maintained near the set take-up speed.

A specific example of control by this computer 8 is shown in No. 21121(a).
.

To explain with reference to (b), Fig. 2 (a) shows the collection 1f.
The change in the take-up speed ■2 of i4 (the vertical axis is the take-up speed ■2, the horizontal axis is time), and the figure (b) shows the change in the feed-out speed ■1 of the feed-out device 2 (the Mi-axis is the feed-out speed V1, the horizontal axis is the time). time)
This indicates that the take-up speed ■2 is sampled at a sampling time S such as every 2 minutes, and when the take-up speed ■2 at the time of sampling is within the range of the dead zone A, the base material 1
The feed rate ■ is kept the same. Note that the dead zone A is a take-up speed target area that has a certain width above and below the set take-up speed. When the sampled take-up speed V2 exceeds the dead zone A, the part indicated by the arrow (A)), the feeding speed V1 of the base material 1 is changed by one step Δ■, for example.
lower the height. This is repeated until the take-up speed ■2 reaches the dead zone A (in the illustrated example, the dead zone A is set in two stages).
If the sampled take-up speed v2 is below the lower limit of the dead zone A (the part indicated by the arrow (b)), then, contrary to the above, the feed-out speed V is increased by one step Δ. ■Increase by 1 and retract this so that take-up speed ■2 falls within dead zone A. In this way, by controlling the feed speed V1, even if the diameter of the base material 1 varies greatly, the take-off machine 4 always operates within the range of the dead zone A centered on the set take-up speed, that is, in the vicinity of the set take-off speed. Optical fibers can be collected at Thereby, the take-off machine 4 can always be operated near the upper limit of its capacity, thus enabling high-speed operation.

In addition, although the feeding speed is changed in steps in the embodiment, it is also possible to control the feeding speed to be changed continuously. Furthermore, in the embodiment, the delivery speed is controlled by sampling the take-up speed at predetermined time intervals;
It is also possible to control the delivery speed by continuously detecting the take-up speed. In addition, the control of the sending speed in the present invention is performed so as not to affect the control of the outer diameter of the optical fiber.
The period must be sufficiently long compared to this optical fiber outer diameter control.

[Effects of the Invention] As explained above, according to the present invention, the take-off speed of the take-off machine is detected, and the delivery speed of the optical fiber preform is controlled so that this take-off speed is maintained near the set take-off speed. Therefore, even if the diameter of the optical fiber base material changes greatly, it will not exceed the capacity of the pulling machine, and the pulling speed must always be within the capacity of the pulling machine to accommodate changes in the diameter of the optical fiber base material. I can do it. Therefore, the take-up machine can be operated near the upper limit of its capacity, which enables high-speed operation and improves productivity.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the optical fiber spinning method of the present invention;
Fig. 2 explains an example of the feeding speed control according to the present invention.
) is a diagram showing changes in the sending speed (2), and FIG. 3 is a diagram explaining a conventional optical fiber spinning method. 1... Optical fiber base material, 2... Feeding device, 3...
... Heating furnace, 4... Taking machine, 5... Optical fiber, 6
... Outer diameter measuring device, 7... Taking machine control device, 8...
computing machine.

Claims (1)

[Scope of Claims] When spinning an optical fiber by sending out an optical fiber preform at a predetermined sending speed V_1 by a sending device, melting the tip of this optical fiber preform in a heating furnace, and taking it away by a pulling machine, the above-mentioned A light that measures the diameter of the optical fiber to be picked up by a pulling machine and changes the pulling speed V_2 of the pulling machine in accordance with the measured diameter of the optical fiber so that the diameter of the optical fiber to be pulled is kept constant. In the fiber spinning method, a take-up speed V_2 of the take-off machine is detected, and this take-off speed V_2 is detected.
1. An optical fiber spinning method characterized by controlling the delivery speed V_1 of the optical fiber preform so that the take-up speed V_2 is maintained near a set take-up speed.