JPS62147409A - Manufacture of optical connector ferrule - Google Patents

Abstract

PURPOSE:To attain mass-production by metallic mold formation by carrying out resin molding while the tip of a main shaft rod is set in a reinforcing pipe at an interval from the thin-diameter pin part of a fixed pin and then extracting the main shaft rod and fixed pin, and working a hole so that the main shaft rod hole and thin-diameter pin part hole communicate with each other. CONSTITUTION:A positioning member 4 which has a thin hole 41 in the center is set in the lower part of an elastic sleeve 2 by being fitted, the fixed pin 6 having the thin-diameter pin part 61 is provided to the lower part of this positioning member 4 by running the thin-diameter pin part 61 in the thin hole 41, and the lower flange part of the positioning member 4 and the fixed pin 6 are clamped by the lower metallic mold 13 of a metallic mold 1. The main shaft rod 5 and fixed pin 6 are extracted after molding and the hole formed by the thin-diameter pin part 61 of the fixed pin 6 and the hole formed by the main shaft rod 6 are linked with each other by using a drill, etc., to form the insertion hole for an optical fiber core and an optical fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing an optical connector ferrule having a reinforcing pipe on the outer periphery used for positioning and coupling at the end of an optical fiber.

(Prior art) A low-cost optical connector using a plastic-molded optical connector ferrule has already been developed. Generally, a molding shrinkage of .3% to 1% (approximately 7.5 μm to 25 μm at an outer diameter of 2.5 μm) occurs. For this purpose, the outer diameter tolerance, which can be used for single mode optical fibers, is ±0.5 μm, and the eccentricity is 0.5 μm.
It has been extremely difficult to manufacture plastic molded optical connector ferrules with ultra-high precision of micrometers or less.

In response, we have developed an optical connector ferrule in which a reinforcing pipe made of metal or ceramic whose outer diameter has been machined with high precision is set in a mold in advance, and then this is insert-molded to provide a reinforcing pipe on the outer periphery. It has been done.

FIG. 3 is a schematic vertical cross-sectional view of a mold for manufacturing such an optical connector ferrule having a reinforcing pipe on its outer periphery.

In the drawing, (1) is the mold, the mold body is 00, the upper mold (
IZ and a lower mold (1'J). A metal or ceramic positioning member (A) having a pore (41) is set at the bottom of the mold body OD, and the upper mold A reinforcing pipe (3) made of metal or ceramic whose outer diameter has been machined with high precision is set inside the mold body oD, and the reinforcing pipe (3) also has a small diameter part (51) at its tip.
The molded pin (5') that has a small diameter part (51') at the tip
) is inserted into the pore (41) of the positioning member (2). In this state, resin is injected from the sprue Qr3 of the mold and molded, and then the molded pin (5') is pulled out to obtain an optical connector ferrule having a reinforcing pipe (3) on its outer periphery.

(Problem to be solved) Regarding the outer diameter accuracy, by using a reinforcing pipe with an outer diameter tolerance of ±0.5 μm, the problems of conventional plastic molded optical connector ferrules are solved, and mass productivity is high (and high precision is achieved). This made it possible to manufacture optical connectors with high performance.

However, it has never been easy to suppress the eccentricity of the optical fiber guide hole or the optical fiber itself to 0.5 μm or less with respect to the outer diameter. This is because a clearance of 1 μm or more is usually required to insert the reinforcing pipe into the mold, and in reality, due to the eccentricity caused by this clearance, it is extremely difficult to suppress the final eccentricity to 0.5 μm or less. It was difficult. Furthermore, although a positioning member having a small hole for positioning the forming pin or the tip of the optical fiber is set at the bottom of the mold, eccentricity has also occurred due to the fitting between this positioning member and the mold.

The above factors also affect optical connector ferrules manufactured by insert molding reinforcing pipes, resulting in zero
．． It has been extremely difficult to mass-produce optical connector ferrules with an eccentricity of 5 μm or less by mold molding.

(Means for Solving the Problems) The present invention overcomes the above-mentioned problems and provides a method for manufacturing optical connector ferrules that can manufacture highly accurate optical connector ferrules with high mass productivity.The present invention has the following characteristics: A mold is equipped with an elastic sleeve having a split in the length direction on its inner surface, and a positioning member in which a small-diameter pin portion of a fixing pin is inserted through a central hole is attached to one end of the elastic sleeve, and a reinforcing pipe is attached to the other end. Then, resin molding is performed with the main spindle rod set in the reinforcing pipe with its tip kept spaced from the small diameter pin part of the fixing pin, and then the main spindle rod and the fixing pin are pulled out and the main spindle The purpose is to machine the hole so that the rod hole and the small diameter pin hole communicate with each other.

(Example) Fig. 1 is a schematic vertical sectional view of a mold in the manufacturing method of the present invention, Fig. 2 is a perspective view of an elastic sleeve used in the present invention, and the same symbols as in Fig. 3 represent the same parts. ing.

The manufacturing method of the present invention basically consists of insert molding a reinforcing pipe such as a metal pipe or ceramic pipe whose outer diameter has been machined with high precision, similar to the method shown in FIG. The difference from the method shown in Fig. 3 is that an elastic sleeve with longitudinal slots is provided on the inner surface of the mold.

A metal elastic sleeve (2) with longitudinal splits (2 summers) as shown in FIG. 2 is attached to the inner surface of the mold body GD. This elastic sleeve (■) is clamped between the middle plate 041 of the mold (1) and the lower flange of the positioning member (4), which will be described later, so that it appears as if it were built into the mold (1). There is no possibility that it will come out when the molded product is released.

A positioning member (2) having a small hole (41) in the center is fitted into the lower part of the elastic sleeve (2), and the lower part of this positioning member (4) has a small diameter pin part (
61) is provided by inserting the small diameter pin part (81) into the above small diameter (4K), and the lower flange part of the positioning member (4) and the fixing pin (6) are attached to the mold ( 1)
It is clamped by the lower mold (13). Also, a reinforcing pipe (3) such as a metal pipe or ceramic pipe is inserted and set in the upper part of the elastic sleeve (2) using its elasticity. By doing so, conventional 1
Reinforcement pipes (3) and molds (1) that were required for micrometers or more
It has become possible to reduce the clearance with the inner surface to zero. In addition, conventional fitting problems have arisen regarding the fixation of the positioning member (4) in the mold, but in the present invention, the positioning member (Φ) is fixed by the elastic sleeve (■), so the clearance here is also zero. be able to.

A main shaft rod (■) is set in the center of the reinforcing pipe (3) with its tip maintained at a distance from the tip of the small diameter pin part (81) of the fixing pin (■), and in this state, resin is applied from the sprue GSI. Inject and mold.

After molding, pull out the main shaft (■) and the fixing pin (■), and then use a drill or the like to connect the hole formed by the small diameter pin part (811) of the fixing pin (■) with the hole made by the main shaft (■) to form the optical fiber core. An optical connector ferrule is obtained in which an insertion hole for an optical fiber is formed and a reinforcing pipe (2) is provided on a part of the outer periphery.

(Prototype example) A ceramic positioning member (2) with a total length of 5 m, an outer diameter of 2.499±Q, 0001 mm, an eccentricity of 0.2 μm or less, and a pore of 129 ZZmφ in the center is installed at the total length of 1
It was attached to one end of an elastic sleeve (2) with a lengthwise split of about 0.5 inches (0.3 inches thick). At the bottom of the positioning member (4), there is a fixing pin (6) with a small diameter pin part (6I) of 128 μmφ at the tip.
The positioning member (1) is inserted through the small hole (4 holes) of Φ, and the lower flange part of the positioning member (4) and the lower part of the fixing pin 0 are clamped by the lower mold q3. The tip of the small diameter pin part (81) is connected to the positioning member (2).
) stands out by about 2 points.

Successfully, a stainless steel pipe (2) with a length of IOO12 and an outer diameter of 2.499±0.0001 (2) was inserted into the other end of the elastic sleeve (2) and set in the mold (1) in such a state. As shown in FIG. 1, this stainless steel pipe (3) is designed to be embedded approximately 211 times into the flange of the ferrule.

A spindle rod ■ with a diameter of 1 wsmφ is set in the center of this stainless steel pipe ■ so that its tip maintains a distance from the tip of the small diameter pin part (81), and in this state, molding is performed using epoxy resin at a temperature of 175°C. , molding pressure 50 kg/cm”
Molded with. After forming, pull out the main shaft ■ and fixing pin ■,
The hole formed by the main shaft rod and the small diameter pin part of the fixing pin is drilled using a drill to communicate with each other to form an insertion hole for the optical fiber core and the optical fiber, and a stainless steel pipe is attached to a part of the outer periphery. We obtained an optical connector ferrule with a ferrule.

The resulting optical connector ferrule has a part of its outer circumference made of stainless steel pipe, and the tip is made of resin. It protrudes in a tapered shape of 10 degrees, and the diameter of the tip is approximately 0.8 mm.

This is because a groove is provided in the positioning member so that there is no need to grind the stainless steel pipe during grinding. The outer diameter of the obtained optical connector ferrule is naturally 2.499±0.
．． 0001■-, and the eccentricity was n = tGo, average 0.32 μm, maximum OJ μmz, minimum 0.1 μm or less.

(Effects of the Invention) The method for manufacturing an optical connector ferrule of the present invention described above provides the following effects.

■In the conventional pipe insert method, the eccentricity caused by the clearance when inserting the pipe into the mold is significantly reduced in the present invention by attaching an elastic sleeve to the inner surface of the mold, and the fixed clearance between the positioning member and the mold is reduced. It was also possible to significantly reduce the eccentricity caused by this.

■ Conventionally, the inner surface machining accuracy of the mold needed to be ±1 μm, but in the present invention, an elastic sleeve is attached to the inner surface of the mold, so ±10 μm is sufficient, making the mold easy to manufacture at a low cost. It became possible to create.

■Insertion of the reinforcing pipe into the mold and removal of the molded product are done through the elastic sleeve, making it extremely easy.

■Previously, there was the problem of thermal deformation of the mold, and it was necessary to determine the inner diameter by taking the molding temperature into consideration, but since ceramic is used for the positioning member and an elastic sleeve is used, it is possible to prevent thermal deformation. It is relatively stable and enables high-precision molding.

■Since the inner surface of the mold is made of an elastic sleeve, there is extremely little effect on eccentricity due to inner wear, and the mold can be reused by simply replacing the elastic sleeve, making it extremely easy to mass-produce and maintain. .

In the above-mentioned prototype example, a stainless steel pipe was used as the reinforcing pipe, but of course a ceramic pipe could also be used, and an epoxy resin was used as the molding resin, but it goes without saying that other resins can be used.

[Brief explanation of drawings]

Fig. 1 is a schematic longitudinal sectional view of a mold in the manufacturing method of the present invention, Fig. 2 is an explanatory diagram of an elastic sleeve used in the present invention, and Fig. 3
The figure shows a schematic vertical cross-sectional view of a mold in a conventional manufacturing method. DESCRIPTION OF SYMBOLS 1... Mold, 2... Elastic sleeve, 3... Reinforcement pipe, 4... Positioning member, 4... Pore, 5...
Main shaft rod, 6... Fixed pin, 81... Small diameter pin part. Figure 1

Claims (1)

[Claims] (1) A mold with an elastic sleeve split in the length direction attached to the inner surface. A positioning member is inserted into one end of the elastic sleeve and the small diameter pin part of the fixing pin is inserted into the central hole, and the other end is reinforced. After setting the pipe, resin molding is performed with the main shaft rod set in the reinforcing pipe with its tip kept spaced from the small diameter pin part of the fixed pin, and then the main shaft rod and the fixed pin are pulled out. A method for manufacturing an optical connector ferrule, characterized by drilling a hole so that a main shaft rod hole and a small diameter pin hole communicate with each other.