JPH06211536A - Glass fiber manufacturing method - Google Patents

Abstract

(57) [Summary] [Object] To provide a method of manufacturing a glass fiber, which can eliminate the influence of various disturbances and stabilize the glass fiber by converging it to a constant diameter in a short time. [Structure] The glass member 3 is sent into the electric furnace 11 by the sending-out mechanism portion 13, and the glass member 3 which is melted in the electric furnace 11 and hangs downward from the opening 1103 is pulled out vertically downward by the pulling-out mechanism portion 14. When forming the glass fiber 5, the wire diameter of the formed glass fiber 5 is measured by the wire diameter measuring unit 17, and is drawn out based on the difference between the measured wire diameter of the glass fiber 5 and a predetermined reference wire diameter. Glass member 3 melted by mechanism section 14
When the difference between the drawing speed and the predetermined reference speed is out of a predetermined range, the drawing speed of the glass member 3 is fed by the sending mechanism section 13 together with the drawing speed of the glass member 3. The speed is increased or decreased under the control of the control unit 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass fiber manufacturing method for obtaining a glass fiber from a molten glass member.

[0002]

2. Description of the Related Art Generally, a glass fiber is formed by feeding a glass member into a melting furnace, heating and melting the glass member, and pulling out a lower portion of the melted glass member vertically downward from the melting furnace. Then, in forming the glass fiber in the above-mentioned step, conventionally, in order to keep the wire diameter of the glass fiber constant, the wire diameter of the glass fiber formed by the drawer is measured, and the value is a predetermined reference value. The speed of drawing the lower part of the glass member downward in the vertical direction from the melting furnace was controlled to be increased or decreased according to the difference between the two values.

[0003]

However, if it is attempted to keep the diameter of the glass fiber constant by controlling only the speed at which the lower part of the glass member is drawn vertically downward from the melting furnace, the fluctuation range of the drawing speed becomes large. Has become
The time required for the glass fiber to converge to a constant diameter and stabilize becomes long. In addition to this, in the control that only changes a single element of the drawing speed, the time required for the glass fiber to converge to a constant wire diameter and stabilize is dependent on the ambient conditions other than the drawing speed, that is, , It will be greatly affected by various disturbances. Therefore, the production time of the glass fiber varies depending on the degree of increase or decrease of the drawing speed and various disturbances, and when the glass fibers are mass-produced by operating a plurality of devices, the production time of each device varies. There was a problem that it became big.

Further, in keeping the wire diameter of the glass fiber constant by controlling the drawing speed, when the drawing speed is changed by reacting sensitively to the change in the measured wire diameter of the glass fiber, the various disturbances are caused. Will be easily affected by. Therefore, conventionally, in order to eliminate the influence of various disturbances, a method of calculating the average value of the wire diameter of the glass fiber at regular time intervals and controlling the drawing speed according to the average value has been taken. .

In this case, the longer the fixed time, the less likely it is to be affected by the disturbance. However, on the other hand, the reaction of the change in the diameter of the glass fiber with respect to the control of the drawing speed becomes poor, and it takes a long time until the glass fiber converges to a constant diameter and becomes stable. It causes a problem. Therefore, it is very difficult to set the width of the constant time so that the time required for the glass fiber to converge to a constant wire diameter and stabilize can be shortened and the influence of the disturbance can be reduced. It was very difficult.

Further, in performing control for keeping the wire diameter of the glass fiber constant, conventionally, when the wire diameter of the glass fiber exceeds a predetermined reference wire diameter, control is performed to reduce the wire diameter of the glass fiber. On the contrary, when the wire diameter of the glass fiber falls below a predetermined reference wire diameter, control is performed to increase the wire diameter of the glass fiber. However, for example, when the wire diameter of the glass fiber exceeds the predetermined reference wire diameter, but the difference between the two is decreasing with time,
If the simple control of reducing the diameter of the glass fiber is performed, it is spurred to the extent that the difference between the diameter of the glass fiber and the predetermined reference diameter is reduced. Even after the difference between the reference wire diameter and the reference wire diameter disappeared, the control to reduce the wire diameter of the glass fiber was sometimes continued for a while.

If the control for reducing the wire diameter of the glass fiber is continued for a while even after the difference between the both is eliminated, the wire diameter of the glass fiber becomes smaller than a predetermined reference wire diameter, and the difference between the two increases. However, this time, the reverse control had to be performed, and there was a problem that it took a long time for the glass fiber to converge to a certain diameter and stabilize. Then, the longer the control for decreasing the wire diameter of the glass fiber is continued for a while, the greater the difference between the wire diameter of the glass fiber and the predetermined reference wire diameter becomes, and the more the glass fiber becomes constant. It took longer to reach the wire diameter.

Further, when the wire diameter of the glass fiber is below a predetermined reference wire diameter, but the difference between the two is decreasing with time, a simple control of increasing the wire diameter of the glass fiber was performed. Also in the case, similarly to the above, control for increasing the wire diameter of the glass fiber is performed for a while after the difference between the two disappears, and the glass fiber turns to a direction in which the difference between the two increases, and the glass fiber has a constant line. There was a problem that it took a long time to converge on the diameter and stabilize.

In order to prevent the above-mentioned problems from occurring, an operator determines the diameter of the glass fiber and the situation such as the difference between the diameter and the reference diameter, and undershoots or overshoots. It is necessary to control the diameter of the glass fiber so as not to be in a state, which increases the burden on the operator and sets the condition of how to increase or decrease the diameter of the glass fiber according to the situation. There was a problem that it was difficult to do.

The present invention has been made in view of the above problems, and its first object is to eliminate the influence of various disturbances when performing control for keeping the diameter of a glass fiber constant. In order to provide a glass fiber manufacturing method capable of converging and stabilizing the glass fiber to a constant diameter in a short time, the second object is to provide a glass fiber having a diameter equal to that of the glass fiber. An object of the present invention is to provide a glass fiber manufacturing method capable of preventing an undershoot or an overshoot from occurring during control and more efficiently converging and stabilizing the glass fiber to a constant wire diameter.

[0011]

In order to achieve the first object, the present invention according to claim 1 sends a glass member into a melting furnace, heats and melts the glass member, and melts in the melting furnace. When forming the glass fiber by pulling the lower part of the glass member downward in the vertical direction from the melting furnace, the wire diameter of the glass fiber formed is measured, and the wire diameter of the measured glass fiber and a predetermined reference line. Calculate the difference with the diameter, based on the difference in the calculated wire diameter, increase and decrease control the pulling speed of the lower portion of the lower portion of the molten glass member in the vertical direction, and measure the pulling speed,
The difference between the measured drawing speed and a predetermined reference speed is calculated, and when the difference between the calculated speeds is out of a predetermined range, the pulling speed increase / decrease control is performed in the melting furnace of the glass member. It is characterized in that the feeding speed to and from is controlled to be increased or decreased.

In order to achieve the above-mentioned second object, the present invention according to claim 2 is to send the glass member into a melting furnace to heat and melt the glass member, and to melt the glass member in the melting furnace. When forming the glass fiber by pulling the lower part downward in the vertical direction from the melting furnace, the wire diameter of the formed glass fiber is measured, and the difference between the measured wire diameter of the glass fiber and a predetermined reference wire diameter. The difference between the calculated wire diameters is out of a predetermined range, and when the measured wire diameter of the glass fiber is larger than the reference wire diameter, the difference in the wire diameters is calculated. The first control for proportionally reducing the wire diameter of the glass fiber is performed, the difference between the calculated wire diameters is outside a predetermined range, and the measured wire diameter of the glass fiber is the reference. If it is smaller than the wire diameter, the wire diameter The second control for increasing the wire diameter of the glass fiber in proportion to the amount of the difference is performed, and the difference between the calculated wire diameters is within a predetermined range, and the measured wire of the glass fiber is When the amount of change in diameter per unit time is positive, the third control for reducing the wire diameter of the glass fiber is performed, and the calculated difference in wire diameter is within a predetermined range, and A fourth control for increasing the wire diameter of the glass fiber is performed when the amount of change in the wire diameter of the measured glass fiber per unit time is negative. Furthermore, in the present invention according to claim 3, in the first and third controls, the lowering speed of the lower portion of the molten glass member in the vertical direction is increased, and in the second and fourth controls. The withdrawal speed was reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a glass fiber manufacturing apparatus to which the method of the present invention is applied.

In FIG. 1, a glass fiber manufacturing apparatus indicated by the general reference numeral 1 is an electric furnace 11 and an electric furnace 11.
A feeding mechanism 13 for feeding the glass member 3 having a triple structure of a core, a clad, and an acid-soluble glass, and a glass fiber 5 obtained by stretching the glass member 3 melted in the electric furnace 11 is drawn downward. Drawer mechanism section 14
And a gas burner 16 for cutting the glass fiber 5 drawn downward by the drawing mechanism portion 14 into a predetermined length.

Further, the glass fiber manufacturing apparatus 1 is
Wire diameter measuring unit 17 for measuring the wire diameter of the glass fiber 5
Based on the wire diameter of the glass fiber 5 measured by the wire diameter measuring unit 17, the downward pulling speed of the glass fiber 5 by the pulling mechanism unit 14 is controlled, and based on the pulling speed. Further, there is further provided a control unit 19 for controlling the feeding speed of the glass member 3 into the electric furnace 11 by the feeding mechanism unit 13.

The electric furnace 11 has a heating section 1101 therein, and the glass member 3 fed by the feeding mechanism section 13 is heated and melted by the heating section 1101. Further, the electric furnace 11 is provided with an opening 1103 in the lower part thereof, and the glass member 3 heated and melted by the heating unit 1101 hangs down from the opening 1103 to the lower side of the electric furnace 11.

The feeding mechanism section 13 is composed of a cylinder 1301 such as a hydraulic cylinder or a solenoid, and the electric furnace 11
Is disposed above. The cylinder 1301 is provided with a retractable rod 1303, the tip of which extends downward and is applied to the upper end of the glass member 3. Therefore,
When the rod 1303 of the cylinder 1301 extends downward, its tip comes into contact with the upper end of the glass member 3 and presses the glass member 3 downward, whereby the glass member 3 is fed into the electric furnace 11. The extension speed of the rod 1303 is changed by the control of the control unit 19.

The pull-out mechanism section 14 includes a pair of rollers 140.
1 and a motor 1403 for rotating one of the rollers 1401 in the direction of arrow X in FIG.
It is arranged below 1. The opening 1103 of the electric furnace 11
The glass member 3 hanging down from the above is sandwiched by the pair of rollers 1401, and one roller 1401 is rotated in the arrow X direction by the rotation of the motor 1403, and the glass member 3 is sandwiched by the pair of rollers 1401. When the glass member 3 is pulled out downward in the vertical direction as it is, the glass member 3 that has hung down is stretched above the pair of rollers 1401 to form the glass fiber 5.

After that, the glass fiber 5 is pulled out in the vertical direction by the rotation of the motor 1403 and the pair of rollers 1401, and by this pulling out, the hanging glass member 3 is continuously drawn.
The rotation speed of the motor 1403 is changed by the control of the control unit 19.

The gas burner 16 includes a pair of rollers 1401.
The glass fiber 5 that is pulled out vertically downward by sandwiching and rotating is cut into a predetermined length, and is disposed below the pair of rollers 1401 in a position facing the pulling path of the glass fiber 5. The ignition timing of the gas burner 16 is controlled by the controller 19.

The wire diameter measuring unit 17 measures the wire diameter of the glass fiber 5 mechanically or electrically, and is arranged below the electric furnace 11 and above the drawing mechanism unit 14. The wire diameter of the glass fiber 5 obtained by stretching the glass member 3 hanging from the opening 1103 of the electric furnace 11 is measured here, and the measurement result is the control unit 19
Transferred to.

The control unit 19 is composed of, for example, a microcomputer, and controls the rotation speed of the motor 1403 of the drawing mechanism unit 14 according to the wire diameter of the glass fiber 5 measured by the wire diameter measuring unit 17. In addition, the control unit 19
Controls the rotation speed of the motor 1403, and at the same time always grasps the current speed of the motor 1403.
Of the feed mechanism unit 13 depending on the rotation speed of the
Control the extension rate of 03. Further, the control unit 19 controls the ignition timing of the gas burner 16 according to the rotation speed of the motor 1403.

Next, the operation of the glass fiber manufacturing apparatus 1 having the above configuration will be described. The glass member 3 is set in the electric furnace 11, and the cylinder 13 of the feeding mechanism unit 13 is set.
When the No. 01 rod 1303 is extended downward by the control of the control unit 19, the glass member 3 is fed into the electric furnace 11 at a speed of, for example, about 2 mm / min, and heated and melted by the heating unit 1101. The molten glass member 3 is an electric furnace 11
Although it does not appear in FIG. 1 though it hangs down from the opening 1103, it reaches the drawer mechanism unit 14.

The glass member 3 which has reached the drawer mechanism section 14
1 is sandwiched by a pair of rollers 1401 rotating in the direction of the arrow in FIG. 1 and pulled out vertically downward, whereby the glass member 3 is stretched above the sandwiched portion by the pair of rollers 1401. Then, after that, the pair of rollers 1401
With the rotation of, the upper glass fiber 5 is sequentially sandwiched by the pair of rollers 1401 and drawn downward, and the drawing operation is continuously repeated.
For example, the glass fiber 5 has a wire diameter of about 300 μ.

If the glass fiber 5 has a predetermined wire diameter by controlling the rotational speed of the motor 1403 of the pulling mechanism section 14 and the extension speed of the rod 1303 of the feeding mechanism section 13 by the control section 19 described later, the gas burner 16 Perform cutting work. This cutting operation is for making the glass fiber 5 into a predetermined length suitable for producing an optical fiber bundle by a device (not shown) in the next stage, and is performed as follows.

A pair of rollers 140 of the drawer mechanism unit 14
1 rotates while sandwiching the glass fiber 5, the glass fiber 5 is pulled out below the pair of rollers 1401, and its tip passes by the side of the gas burner 16 and further moves downward by a predetermined length, at that point. The gas burner 16
Is ignited, and the glass fiber 5 is cut by the fire of the gas burner 16. The cutting of the glass fiber 5 by the gas burner 16 is repeated every time the glass fiber 5 is pulled downward by a predetermined length as the pair of rollers 1401 rotate.

The glass fiber 5 after cutting naturally falls by its own weight and is aligned by a receiving tray (not shown) below. The cut and arranged glass fibers 5 are cut off at both end portions including the portion sandwiched by the sandwiching portion 1519, and then bundled into a unit of tens of thousands by the device (not shown) at the next stage, and then heated and melted again. , And drawn to form a desired optical fiber bundle.

When the pair of rollers 1401 starts drawing the glass fiber 5 downward, the wire diameter of the glass fiber 5 is measured by the wire diameter measuring unit 17 above the pair of rollers 1401. The measurement result is transferred to the control unit 19. The control unit 19 uses the wire diameter measuring unit 1 in order to make the glass fiber 5 have a predetermined wire diameter.
The rotation speed of the motor 1403 of the pullout mechanism unit 14 is controlled according to the wire diameter of the glass fiber 5 measured by No. 7, and at the same time, the rod 1303 of the feeding mechanism unit 13 of the rotation speed of the motor 1403 is controlled. The extension speed is controlled.

Therefore, the control performed by the control unit 19 will be described. First, a case will be described in which the rotation speed of the motor 1403 of the drawing mechanism unit 14 is controlled according to the wire diameter of the glass fiber 5 measured by the wire diameter measuring unit 17.
In controlling the rotation speed of the motor 1403 of the drawing mechanism unit 14, the control unit 19 performs different control depending on whether or not the wire diameter of the glass fiber 5 is within a certain allowable error range, and the glass fiber 5 Even when the wire diameter is within the allowable error range, different control is performed depending on whether the change amount of the wire diameter per unit time is positive or negative.

Then, the control pattern of the rotation speed of the motor 1403 by the control unit 19 will be described with reference to FIG. 2 showing an example of the change over time of the wire diameter of the glass fiber 5 measured by the wire diameter measuring unit 17. In Figure 2, the horizontal axis is time,
The vertical axis represents the wire diameter value of the glass fiber 5. Also,
In FIG. 2, a solid line S is a predetermined reference wire diameter of the glass fiber 5, and a dashed line A above and below the solid line S
1, A2 are the upper limit and the lower limit of the allowable error range.
Both of these values are held in the control unit 19 as data.

As shown in FIG. 2, the wire diameter of the glass fiber 5 measured by the wire diameter measuring unit 17 fluctuates in a substantially sinusoidal shape with the passage of time. Then, the range R in FIG.
In each of the regions R1, R2 and R5, the wire diameter of the glass fiber 5 exceeds the reference wire diameter, but is below the upper limit of the allowable error range, and in each of the regions R3 and R4, the wire of the glass fiber 5 The diameter is below the standard wire diameter, but above the lower limit of the allowable error range. In the area of the range R6, the wire diameter of the glass fiber 5 exceeds the upper limit of the allowable error range.

On the other hand, in each of the regions R1, R4 and R5 among the regions R1 to R5 within the allowable error range, the change amount of the wire diameter of the glass fiber 5 per unit time is positive. In each area of R2, R3,
The amount of change in the diameter of the glass fiber 5 per unit time is negative.

Then, in the region of the range R6 in which the wire diameter of the glass fiber 5 exceeds the upper limit of the allowable error range, the control unit 19 causes the wire diameter of the glass fiber 5 to become thin, and the control wire 19 and the reference wire diameter. In order to reduce the difference, the first control is performed in which the rotation speed of the motor 1403 is increased and the drawing speed of the glass fiber 5 is increased in proportion to the amount of the difference. Although not shown in FIG. 2, the glass fiber 5
In a region in which the wire diameter is less than the lower limit of the allowable error range, the control unit 19 adjusts the amount of the difference such that the wire diameter of the glass fiber 5 becomes thick and the difference between this and the reference wire diameter decreases. A second control is performed in proportion to which the rotation speed of the motor 1403 is decreased and the drawing speed of the glass fiber 5 is decreased.

Next, in each of the ranges R1, R4, and R5 in which the wire diameter of the glass fiber 5 is within the allowable error range and the amount of change in the wire diameter per unit time is positive, The portion 19 performs the third control for increasing the rotation speed of the motor 1403 and increasing the drawing speed of the glass fiber 5 so that the degree of increase in the diameter of the glass fiber 5 becomes dull. In addition, in each of the regions R2 and R3 in which the wire diameter of the glass fiber 5 is within the allowable error range and the amount of change in the wire diameter per unit time is negative,
The control unit 19 reduces the rotation speed of the motor 1403 and reduces the pulling speed of the glass fiber 5 so that the degree to which the diameter of the glass fiber 5 decreases becomes dull.
Control.

By the above-mentioned first to fourth controls,
While the control unit 19 controls the rotation speed of the motor 1403 to increase or decrease, the control unit 19 determines that the rotation speed of the motor 1403 is within the allowable error range of the rotation speed of the motor 1403 stored as data in the control unit 19. It is determined whether or not. When it is determined that the rotation speed of the motor 1403 is out of the allowable range of the rotation speed, the control unit 1
In addition to the increase / decrease control of the rotation speed of the motor 1403 by the first to third controls, 9 indicates the rod 1303 of the feeding mechanism unit 13 so that the rotation speed of the motor 1403 falls within the allowable error range of the rotation speed. Increase / decrease the extension speed.

When the rotational speed of the motor 1403 exceeds the permissible error range of the rotational speed, the control unit 19 controls to reduce the extension speed of the rod 1303, and conversely, the rotational speed of the motor 1403 rotates. When the speed falls below the allowable error range, the control unit 19 controls the rod 13
Control for increasing the extension speed of 03.

As described above, in the method of manufacturing the glass fiber 5 shown in this embodiment, in order to keep the diameter of the glass fiber 5 constant, the pulling mechanism 14 controls the pulling speed of the glass fiber 5 downward. In addition, the feeding speed of the glass member 3 into the electric furnace 11 is controlled by the feeding mechanism 13 when the drawing speed is out of the predetermined allowable error range. Therefore, compared with the conventional method in which only the drawing speed is controlled, until the glass fiber converges to a constant diameter and stabilizes due to ambient conditions other than the drawing speed, that is, under the influence of various disturbances. It is possible to prevent the time required for the operation from fluctuating greatly, and also to prevent the drawing speed from fluctuating greatly.

Therefore, it is possible to prevent the production time of the glass fiber from varying due to the degree of increase or decrease of the drawing speed and various disturbances, and when a plurality of devices are operated to mass produce the glass fiber, It is possible to eliminate variations in production time for each device and to stabilize the glass fiber by converging it to a constant diameter in a short time.

Furthermore, in the method of manufacturing the glass fiber 5 shown in this embodiment, even when the diameter of the glass fiber 5 is within the above-mentioned allowable error range, the change amount of the wire diameter per unit time is positive. Control to increase or decrease the downward drawing speed of the glass fiber 5 by the drawing mechanism unit 14 is performed so that the degree to which the diameter of the glass fiber 5 increases or decreases depending on whether it is negative or negative. I decided to do it. For this reason, under the control of increasing or decreasing the downward pulling speed of the glass fiber 5 by the pulling mechanism section 14, undershoot and overshoot are prevented from occurring, and the wire diameter of the glass fiber 5 is kept constant. It is possible to more efficiently control the drawing speed for maintaining the above, and it is possible to stabilize the glass fiber by converging it to a constant wire diameter in a shorter time.

The glass fiber manufacturing apparatus for carrying out the method of the present invention is not limited to the one having the structure shown in this embodiment. For example, in this embodiment, the glass member 3 is fed into the electric furnace 11 by the rod 130 of the cylinder 1301.
3 has been described, but the upper end of the glass member 3 may be pressed by sliding the pressing plate downward in the vertical direction by the rotation of the motor, and the glass member 3 may be fed into the electric furnace 11. In this case, the rotation speed of the motor for moving the pressing plate downward is controlled according to the drawing speed of the glass fiber.

Further, in this embodiment, the drawer mechanism unit 14
The case where the pair of rollers 1401 rotates while holding the glass fiber 5 and pulls the glass fiber 5 downward in the vertical direction has been described.
The glass fiber 5 may be pulled out in the vertical direction by holding a part of the above with a chuck and moving the chuck downward.

Furthermore, in the present embodiment, the case where the pulling speed of the glass fiber 5 to the lower side by the pulling mechanism portion 14 is controlled in order to keep the wire diameter of the glass fiber 5 constant has been described. Alternatively, the heating temperature of the glass member 3 in the heating unit 1101 of the electric furnace 11 may be controlled up and down. Needless to say, the method of the present invention can be applied not only to the production of glass fibers that form an optical fiber bundle, but also to the production of glass fibers that are individual finished products.

[0043]

As described above, according to the present invention, the glass member is fed into the melting furnace to be heated and melted, and the lower portion of the glass member melted in the melting furnace is vertically downward from the melting furnace. When forming a glass fiber by drawing into, to measure the wire diameter of the formed glass fiber, calculate the difference between the wire diameter of the measured glass fiber and a predetermined reference wire diameter, the calculated line Based on the difference in diameter, while increasing or decreasing the vertical pulling speed of the lower portion of the molten glass member, the pulling speed is measured, between the measured pulling speed and a predetermined reference speed. The difference is calculated, and when the calculated difference in speed is out of a predetermined range, the pulling speed is increased / decreased and the feeding speed of the glass member into the melting furnace is increased / decreased. It was. Therefore, when performing control for keeping the wire diameter of the glass fiber constant, the influence of various disturbances can be eliminated and the glass fiber can be converged to a constant wire diameter and stabilized in a short time.

Further, according to the present invention, the glass member is fed into the melting furnace to be heated and melted, and the lower portion of the glass member melted in the melting furnace is pulled out downward from the melting furnace in the vertical direction. When forming a fiber, the wire diameter of the formed glass fiber is measured, the difference between the wire diameter of the measured glass fiber and a predetermined reference wire diameter is calculated, and the difference between the calculated wire diameters is Outside the specified range,
And when the measured wire diameter of the glass fiber is larger than the reference wire diameter, the first control is performed to reduce the wire diameter of the glass fiber in proportion to the amount of the difference between the wire diameters, and the calculation is performed. The difference in the wire diameters is outside the specified range,
Further, when the measured wire diameter of the glass fiber is smaller than the reference wire diameter, the second control for increasing the wire diameter of the glass fiber in proportion to the amount of the difference in the wire diameter is performed, and the calculation is performed. The difference between the wire diameters is within the specified range,
Further, when the amount of change in the measured wire diameter of the glass fiber per unit time is positive, the third control for reducing the wire diameter of the glass fiber is performed, and the difference between the calculated wire diameters is performed. Is within a predetermined range and the amount of change in the measured wire diameter of the glass fiber per unit time is negative, a fourth control for increasing the wire diameter of the glass fiber is performed. I chose Therefore, when controlling the wire diameter of the glass fiber, it is possible to prevent undershoot and overshoot from occurring, and to more efficiently converge and stabilize the glass fiber to a constant wire diameter.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a glass fiber manufacturing apparatus to which the method of the present invention is applied.

FIG. 2 is an explanatory diagram showing an example of a change over time in the wire diameter of the glass fiber measured by the wire diameter measuring unit shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass fiber manufacturing apparatus 11 Electric furnace 1101 Heating part 13 Feeding mechanism part 1303 Cylinder rod 14 Drawing mechanism part 1403 Drawing mechanism part Motor 17 Wire diameter measuring part 19 Control part 3 Glass member 5 Glass fiber

Claims (3)

[Claims] 1. When a glass member is fed into a melting furnace to be heated and melted, and a lower portion of the glass member melted in the melting furnace is pulled out vertically downward from the melting furnace to form a glass fiber, The wire diameter of the formed glass fiber is measured, the difference between the wire diameter of the measured glass fiber and a predetermined reference wire diameter is calculated, and based on the difference between the calculated wire diameters, the melted While controlling the pulling speed of the lower part of the glass member downward in the vertical direction, the pulling speed is measured, the difference between the measured pulling speed and a predetermined reference speed is calculated, and the calculated speed is calculated. When the difference between the two is out of a predetermined range, the feeding speed of the glass member into the melting furnace is controlled to be increased / decreased together with the increase / decrease control of the drawing speed. Method of manufacturing a Sufaiba. 2. When a glass member is fed into a melting furnace to be heated and melted, and a lower portion of the glass member melted in the melting furnace is pulled out vertically downward from the melting furnace to form a glass fiber, The wire diameter of the formed glass fiber is measured, the difference between the wire diameter of the measured glass fiber and a predetermined reference wire diameter is calculated, and the difference between the calculated wire diameters is outside a predetermined range. And, when the wire diameter of the measured glass fiber is larger than the reference wire diameter, a first control is performed to reduce the wire diameter of the glass fiber in proportion to the amount of the difference in wire diameter, When the calculated wire diameter difference is outside a predetermined range, and when the measured glass fiber wire diameter is smaller than the reference wire diameter, the wire diameter difference is proportional to the amount. To increase the diameter of glass fiber Control, the difference in the calculated wire diameter is within a predetermined range, and, when the amount of change per unit time of the measured wire diameter of the glass fiber is positive, While performing the third control for reducing the wire diameter, the calculated difference in wire diameter is within a predetermined range, and the amount of change in the measured wire diameter of the glass fiber per unit time is negative. At this time, the fourth control for increasing the wire diameter of the glass fiber is performed. 3. The pulling speed of the lower portion of the melted glass member in the vertically downward direction is increased in the first and third controls, and the pulling speed is decreased in the second and fourth controls. The method for manufacturing a glass fiber according to claim 2, wherein.