JP2870548B2 - Manufacturing method of preform - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing an optical fiber, and more particularly to a method for manufacturing an optical fiber suitable for increasing the size of a preform.

[Conventional technology]

The optical fiber is usually drawn, for example, by pulling in one direction while heating one end of a so-called preform in a heating furnace with a glass rod previously formed into a substantially cylindrical shape, thereby drawing an optical fiber having a constant outer diameter. An element wire is formed, and then a predetermined resin is applied to the outer peripheral surface, and then wound around a bobbin or the like.

By the way, as a method for manufacturing the preform, for example, as shown in FIG. 3, a soot 102 is attached to an outer peripheral surface of a dummy rod 101 which is arranged in a horizontal direction and both ends of which are rotatably supported by a chuck 100. A method of forming by depositing is known, and after forming into a predetermined size, one end side is cut into a shape as shown in FIG. 4 by a burner 103 or the like.

[Problem to be solved]

By the way, as a method of manufacturing such a preform, a dummy bar is generally turned sideways as described above,
That is, they are arranged in the horizontal direction, and therefore, when a large-sized product is formed, it may be bent by its own weight and a distorted one may be formed.

In addition, if the cutting is performed in such a state where the preform is cut sideways, there is a risk that the large-sized one having a heavy weight cannot be supported by only one of the chucks immediately after the cutting, and may be dropped. I have.

In view of the above-mentioned conventional drawbacks, the present invention provides a method of manufacturing and processing a preform which is particularly suitable for upsizing and which can reliably form a predetermined shape without distortion. It is intended for.

[Means for solving the problem]

That is, the present invention forms a preform by adhering and depositing soot on its outer peripheral surface while rotating a dummy rod supporting both ends by a chuck, and forming one end of the preform into a shape suitable for drawing. In the method of manufacturing and processing a preform to be cut and processed, the dummy rod is disposed in a vertical direction in which gravity acts, and after forming the preform in this state, the lower end of the preform is formed into a spindle shape. Cutting and processing.

[Action]

In the method for manufacturing and processing a preform of the present invention, by arranging the dummy rods forming the preform in the vertical direction in which gravity acts, for example, the right and left shapes are large even if they are gravitationally heavy and large. Deformation into distortion can be prevented.

Further, according to the method of manufacturing and processing a preform of the present invention, even if the lower end of the preform is cut, it can be supported by the upper chuck, thereby making it heavy and large. Even if there is, the lower end of the preform can be reliably cut and processed.

〔Example〕

Hereinafter, the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a method for manufacturing a preform according to the present invention. In this manufacturing method, the dummy rod 3 shown in FIG. The method includes a first step 1 for forming the reform 5 and a second step 2 for processing and cutting the lower end of the formed preform 5.

In the first step 1, soot of quartz glass is placed on the outer peripheral surface of the rotating dummy rod 3 by a predetermined method such as a CVD method (chemical vapor deposition method) or a VAD method (gas phase attachment method). After being deposited and deposited to a predetermined thickness and a predetermined length, it is heated to a specific temperature to form a transparent quartz glass.

The above-mentioned dummy rod (quartz tube rod) 3 has both ends rotated at the same angular velocity by a driving motor 6 via a pair of chucks 4 arranged vertically in a vertical direction. The lower motor 6 is fixed to the casing 7, and the casing 7 moves the lower end of the dummy rod 3 downward when the lower end of the preform 5 is heated and cut by the burner 10 in the second step 2. To be pulled downward by the motor 9 via the wire 8.

In the second step 2, the preform 5 is placed in the direction in which the preform 5 was formed in the first step 1, that is, in the vertical direction, and while being rotated at a constant speed from both ends by the motor 6, While lowering the lower end by the driving force of the motor 9, the burner 10
Thus, the lower end is heated so as to be cut into a spindle shape which is easy to draw.

The specific means of the rotation drive mechanism and the tension mechanism of the dummy rod 3 are not limited to those of this embodiment, but may be any as long as they have the same effect.

〔effect〕

As described above, according to the method for manufacturing and processing a preform according to the present invention, the dummy rods are arranged in the vertical direction in which gravity acts, so that even a large preform having a large weight can have its own weight. Therefore, the left and right sides are not deformed to be deformed in shape, and a large or small shape can be always formed without distortion.

Further, according to the method for manufacturing and processing a preform according to the present invention, the lower end side is cut in a state where the preform is arranged in the vertical direction, and the upper end of the preform immediately after the cutting is used to hold the preform. Can be held in
Cutting can be performed even for a large-sized heavy one, which is suitable for manufacturing a large-sized preform.

[Brief description of the drawings]

FIG. 1 is a step diagram showing a preform manufacturing method according to the present invention, FIG. 2 is a configuration diagram showing a preform manufacturing method using the manufacturing method according to the present invention, and FIG. FIG. 4 is an explanatory view showing a preform manufacturing method, and FIG. 4 is an explanatory view showing a cut preform. 4 ... Chuck, 3 ... Dummy stick, 5 ... Preform.

Claims (1)

(57) [Claims] 1. A preform (5) is formed by depositing and depositing soot on its outer peripheral surface while rotating a dummy bar (3) whose both ends are supported by a chuck (4). In the method of manufacturing and processing a preform (5) in which one end of (5) is cut and processed into a shape suitable for drawing, the dummy bar (3) is disposed in a vertical direction where gravity acts. Forming a preform (5) in step (1), and then cutting and processing the lower end side of the preform (5) into a spindle shape.