JPH0938993A - Ferrule molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ferrule molding method which can mass-produce stably a highly accurate ferrule capable of restraining the connecting loss of an optical connector small, and minimize deterioration of a molding pin. SOLUTION: This ferrule molding method molds ferrule with resin for optical fiber connector having a pin hole and a fiber hole by positioning the first core for forming the pin hole and the second core for forming a fiber hole in a mold having an upper mold 12 and a lower mold 11 and tightening them. Each of the upper mold and the lower mold is constituted of the first mold 12a for tightening the first core and the second mold 12b for tightening the second core. While adjusting the tightening pressure of the first and second molds to their proper values respectively, ferrule is molded.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a ferrule molding method by resin molding.

[0002]

2. Description of the Related Art Ferrules for optical fiber connectors are
Since it is necessary to position the optical connectors when they are butt-connected to each other, for example, like the ferrule 1 shown in FIG. 3, pin holes 1a and 1a for inserting the fitting pins to position the ferrules and the optical fiber are inserted. And a plurality of fiber holes 1b that are fixed by adhesion.

The ferrule 1 is processed into an optical connector, and the pin hole 1 is used for the purpose of suppressing the connection loss when it is butt-connected to another optical connector as much as possible.
The molding accuracy in the positional relationship of a and fiber hole 1b is
It is required in the submicron order of 1 μm or less. In order to manufacture a ferrule that meets such requirements, for example, in Japanese Unexamined Patent Publication No. 6-167638, a plurality of V grooves formed in a lower mold according to the diameter of a molding pin (core pin) to be arranged is shown in FIG. Each of the pin holes 1a, 1a shown in FIG. 3 and the molding pins for molding the plurality of fiber holes 1b are positioned to clamp the lower mold and the upper mold, and each of the plurality of molding pins is formed by the upper mold. A technique of pressing a V groove to form a resin is disclosed.

[0004]

By the way, the plurality of molding pins have different diameters because the pin holes and the fiber holes to be molded have different diameters. For this reason, in the upper mold and the lower mold, it is difficult to obtain the molding accuracy at the same level on the molding pin side that molds the pin hole and the molding pin side that molds the fiber hole. Could not be pressed.

When molding the ferrule with resin, the upper mold and the lower mold are exposed to high temperature in order to melt the resin. Therefore, when the upper die is pressed to the lower die by the pressing member driven by the air cylinder, smooth operation of the air cylinder is hindered due to air leakage or seizure of the cylinder due to high temperature, and a predetermined mold clamping force cannot be obtained. There was an occasion.

When such a situation occurs, the positioning accuracy of the pin hole or the fiber hole formed by the plurality of forming pins decreases. As a result, not only the yield of the molded ferrules that are non-defective but also the connection loss of the optical connector using this ferrule increases. Moreover, since the pressing force of the plurality of molding pins by the upper mold is not uniform, the pressing force becomes excessive on the molding pin side for molding the pin hole or the molding pin side for molding the fiber hole, and the deterioration of the molding pin is quick. Another problem was that the molding pins had to be replaced frequently.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a ferrule molding method capable of stably mass-producing a highly accurate ferrule which suppresses a connection loss of an optical connector and reducing deterioration of a molding pin. It is an issue.

[0008]

According to the present invention, in order to achieve the above object, a ferrule for an optical fiber connector having a pin hole and a fiber hole is provided with a first core for molding the pin hole. A ferrule molding method in which a second core for molding the fiber hole is resin-molded while being positioned and tightened in a molding die having an upper die and a lower die, wherein an upper die and a lower die of the molding die are provided. One is composed of a first mold for tightening the first core and a second mold for tightening the second core, and the tightening pressure of the first and second molds is The ferrule is molded while adjusting each individually.

Preferably, the tightening pressure is 3 Kg · G / c.
Set within the range of m ² or more and 5 Kg · G / cm ² or less. By molding the ferrule while individually adjusting the tightening pressures of the first and second molds, the ferrule can be mass-produced stably with high accuracy. At this time, when the tightening pressures of the first and second molds are set in the range of 3 to 5 kg · G / cm ² , the deterioration of the molding pin is suppressed.

If this tightening pressure is less than 3 Kg · G / cm ^2, it is not preferable because the pressing member which will be described later loses the molding resin pressure and cannot press the molding pin, and the molding pin cannot be accurately positioned. . On the other hand, when the tightening pressure exceeds 5 Kg · G / cm ² , the molding pin is easily deformed, and the deterioration cycle becomes short.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 shows a schematic configuration of a molding apparatus 10 for transfer molding a ferrule with a synthetic resin using the method of the present invention.
Includes a lower mold 11, an upper mold 12, and a pressing mechanism 20.

The lower mold 11 is formed with a cavity (not shown) for molding the ferrule 1 inside the upper mold 12 when clamped as shown in the drawing, and is formed on both sides in the width direction as shown in FIG. Four second V-grooves 11b thinner than the first V-groove 11a are formed in parallel between the formed first V-grooves 11a and 11a at a predetermined pitch. Each first V groove 11a positions the molding pin 5 that molds the pin hole 1a of the ferrule 1.
In addition, each second V-groove 11b positions each molding pin 6 that molds the plurality of fiber holes 1b of the ferrule 1.

The upper mold 12 includes first blocks 12a and 12a.
And a second block 12b, each of which has a runner (not shown) for molding the ferrule 1 in the cavity, for example, for injecting a synthetic resin such as an epoxy resin. There is. First block 1
As shown in FIG. 2, 2a are arranged on both sides of the lower mold 11 in the width direction, and have flat trapezoidal grooves formed on the lower surface. The trapezoidal grooves 2a house the molding pins 5 for molding the pin holes 1a of the ferrule 1. Then, the lower mold 11 is pressed with the first V groove 11a. The second block 12b presses the molding pin 6 for molding the fiber hole 1b of the ferrule 1 and tightens the second V groove 11b of the lower mold 11.

The pressing mechanism 20 includes the first blocks 12a, 1
The tightening pressures of the second block 12a and the second block 12b are individually adjusted. As shown in FIG. 1, the pressing member 21, the lever 22, the support shaft 23, the pressing spring 24, and the adjusting cam 25 are provided. Here, the pressing member 21 and the lever 2
2, the pressing spring 24 and the adjustment cam 25 are provided for each block, but in FIG. 1, in order to prevent each member from being complicated and difficult to see, and to display the drawing easily, Only each member that presses one block 12a is shown.

The pressing member 21 has curved portions 21a, 21a for pressing both sides of the upper surface of the first block 12a or the second block 12b in an inverted T-shaped member, and one end of a lever 22 is connected to the upper portion. . The lever 22 is the support shaft 2.
The circular flange 22 is supported by 3 and presses each block by the lever principle, and the pressing spring 24 abuts on the other end.
a is formed. The push spring 24 has a flange 22a.
And the adjustment cam 25, and applies a pressing force to the pressing member 21 via the lever 22. The adjusting cam 25 is formed so that the radius of the outer peripheral surface thereof expands in a spiral shape around the rotating shaft 25a, and is rotated by an adjusting knob 25b provided at the end of the rotating shaft 25a, so that the pressing spring 24 is rotated. Adjust the spring coefficient and thus the spring force to any value.

In the ferrule molding method of the present invention, the ferrule 1 is molded using the molding device 10 as follows. First, the molding apparatus 10 is opened, and each first mold of the lower mold 11 is opened.
The molding pin 5 is positioned in the V groove 11a, and the molding pin 6 is positioned in each second V groove 11b. Next, the upper die 12 is clamped to the lower die 11, and the respective pressing members 21 press the corresponding blocks of the first block 12a, 12a and the second block 12b.

At this time, in the pressing mechanism 20, the adjusting knob 25b appropriately rotates the adjusting cam 25 in the direction shown by the arrow in the drawing to change the spring coefficient of the pressing spring 24 and press the lever 22 through the lever 22. adjusting the pressing force of the block to be transmitted to the member 21 to any value in the range of ^{3Kg · G / cm 2 ~5Kg ·} G / cm 2. Therefore, by using the pressing mechanism 20, the pressing force for pressing the corresponding blocks of the first block 12a, 12a and the second block 12b, in other words, the tightening pressure for tightening the molding pin 5 or the molding pin 6 by each block is applied. The ferrule 1 can be molded by adjusting each individually.

The first block 1 is formed by each pressing member 21.
2a, 12a and the corresponding blocks of the second block 12b are pressed from the runner of the upper die 12 to the lower die 1
The ferrule 1 is molded by injecting a synthetic resin into the cavity formed between the upper mold 12 and the upper mold 12. After the injected synthetic resin has cooled, the upper die 12 is opened with respect to the lower die 11 and the molding pin 5 and the molding pin 6 are pulled out from the solidified synthetic resin, whereby the ferrule 1 is obtained.

At this time, 1000 ferrules 1 molded by the method of the present invention described above and 1000 ferrules 1 molded by the above-mentioned conventional method were prepared, and optical fibers were inserted into a plurality of fiber holes 1b and bonded. The optical connector was processed into an optical connector and the optical connector processed by the same method was butt-connected and the connection loss was measured. as a result,
The ferrule molded by the method of the present invention has less dimensional variation than the ferrule molded by the conventional method, and the yield of non-defective products is improved. Moreover, in the optical connector using the ferrule molded by the method of the present invention, the average value of the connection loss was considerably smaller than that of the optical connector using the ferrule molded by the conventional method.

By the way, in the conventional case where the pressing member is driven by the air cylinder, the smooth operation of the air cylinder may be hindered due to air leakage or seizure of the cylinder due to high temperature, and a predetermined mold clamping force may not be obtained. There is.
However, the pressing mechanism 2 as in the above-described embodiment of the present invention.
When 0 is used, there is no such concern and a stable mold clamping force can always be obtained.

[0021]

As is apparent from the above description, according to the ferrule molding method of the present invention, it is possible to stably mass-produce a highly accurate ferrule that suppresses the connection loss of an optical connector. At this time, the tightening pressures of the first and second molds are set in the range of 3 Kg · G / cm ² or more and 5 Kg · G / cm ² or less, so that deterioration of the molding pin can be suppressed to a small extent for a long period of time. You can try.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a molding apparatus for transfer molding a ferrule with a synthetic resin using the method of the present invention.

FIG. 2 is a cross-sectional view showing a molding pin positioned by a lower mold and an upper mold.

FIG. 3 is a perspective view of a ferrule molded by the conventional method and the method of the present invention.

[Explanation of symbols]

 1 Ferrule 1a Pin Hole 1b Fiber Hole 5 Molding Pin (First Core) 6 Molding Pin (Second Core) 10 Molding Device 11 Lower Mold 11a First V Groove 11b Second V Groove 12 Upper Mold 12a First Block 12b Second block 20 Pressing mechanism 21 Pressing member 22 Lever 23 Spindle 24 Pushing spring 25 Adjusting cam

Claims (2)

[Claims] 1. A ferrule for an optical fiber connector having a pin hole and a fiber hole, an upper mold having a first core for molding the pin hole and a second core for molding the fiber hole. In a ferrule molding method in which resin molding is performed while positioning and tightening in a molding die having a lower die, one of the upper die and the lower die of the molding die is a first die for fastening the first core. A ferrule characterized by comprising a mold and a second mold for tightening the second core, and molding the ferrule while individually adjusting the tightening pressures of the first and second molds. Molding method. 2. The tightening pressure is 3 Kg · G / cm ² or more, 5
The ferrule molding method according to claim 1, which has a Kg · G / cm ² or less.