JPS61117509A - Production of optical fiber connector - Google Patents

Abstract

PURPOSE:To improve the production efficiency and reliability of a connector by producing a stepped hollow part by a die constituted by inserting the small- diameter top end of a core without support to the center in a cavity part provided successively to a cavity then cutting away the part of the cavity provided successively with said part. CONSTITUTION:The top end of the core 1 is inserted without support to the center in the cavity part 12 provided successively to the cavity 7 and therefore a molten resin is molded without the deficient inflow at the terminal of the resin flow or without having dimensional instability, by which the end face in the large-diameter part of the stepped hollow molding 15 is molded with high accuracy. The durability in the aperture at the insertion port of an optical fiber strand is improved by cutting a small-diameter part 16. The large diameter part and small diameter part 5 of the core 1 are molded concentrically by the self-aligning effect occuring in the fluidity and orientability of the molten resin. The connector which is a final product is simply required to cut away the small-diameter part 16. The production efficiency and reliability of the connector are thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a plastic optical fiber connector.

(Prior art and its problems) In general, optical fiber connectors are manufactured by inserting the optical fiber end portions of the optical fiber core wires to be connected together into a connector by removing the sheathing from the end portions to be connected. By abutting each other and connecting them with a sleeve, the optical fiber strands are abutted against each other in a straight line and mechanically connected. In this type of optical fiber connector, the optical fiber strands and core wire insertion holes of the connector must be precisely processed with an eccentricity of 2 μm or less. When mass-producing such high-precision connectors using plastic, it is first necessary to manufacture connector molds with high precision. Conventionally, this connector is manufactured by manufacturing a cavity insert a, a cavity mold, a stripper C, and a core d using a high-precision machine tool, for example, as shown in FIGS. As shown in the figure, an electroforming master mold θ is manufactured and placed in an electroforming bath consisting of an electroforming bath f, a nickel electrode g, and a power source to form an electroformed body 1. After that, the electroforming master mold e is The electroforming master j was manufactured by processing the outer periphery of the removed electroformed body 1. However, in the former case by machining, the cavity insert a fits into the cavity mold without any gaps when the mold is assembled, and the escape hole of the cavity insert a has very little misalignment with the cavity mold, and the core Since it is necessary to fit and support the small diameter part of the tip of d without any gaps, it requires considerable precision and operator skill, making it difficult to manufacture molds with stable precision. Met. In addition, in the latter case by electroforming, the misalignment between the inner diameter of the electroforming master j and the embedded core t can be minimized depending on the precision of the electroforming master mold θ, but when inserting the optical fiber during plastic molding, Since the hole cannot be made to penetrate, it is necessary to make the hole through by machining after plastic molding, making it unsuitable for mass production. In either case, the connecting end of the connector is molded at the flowing end of the resin, which not only makes it impossible to finish the connecting end of the connector with high precision and a clean appearance, but also prevents the optical fiber element of the connector from being finished. The problem was that the durability of the hole into which it was inserted was poor.

(Object of the Invention) In order to solve the above-mentioned conventional problems, the present invention utilizes the fluidity and orientation of the resin to self-align to the center of the cavity mold without supporting the small-diameter tip of the core. This was created with a focus on the ability to place the connector, and while using a mold that does not require as much precision and is easy to manufacture compared to the conventional core tip insertion support type, it is possible to accurately form the connecting end of the connector. The purpose is to provide a clean appearance and improve the durability of the hole into which the optical fiber element of the connector is inserted.

(Structure of the Invention) The present invention uses a mold in which a small-diameter tip of a core supported and fixed in a cantilever shape inside a cavity is inserted without support into the center of a cavity connected to the cavity. , after producing a stepped hollow molded product by injection molding or the like, the cavity continuous casting portion of the molded product is cut and removed.

(Example) Hereinafter, a mold used for carrying out the present invention will be explained with reference to FIGS. 1 and 2.

In the figure, 1 is a core, in which a large diameter part 2 for forming an optical fiber insertion hole and a small diameter part 3 for forming an optical fiber insertion hole are connected to the same window via a tapered part 4. are doing.

This core 1 is fixedly supported by a movable platen 8 in a cantilever shape so as to be located at the center of a cavity 7 composed of a split 5 and a stripper 6, and the tip of the small diameter portion 3 of the core is It protrudes outside of cavity 7.

9 is a cavity mold, lO is a cavity insert, which is attached to the fixed platen 11, and the cavity 7 is formed by the cavity mold 9 and the cavity insert 10.
A cavity 12 is formed which is connected to the cavity. This cavity part 12 is provided on the same straight line as the core 1, and has a diameter larger than the core small diameter part 3 and smaller than the outer diameter of the cavity 7.
For example, the length is approximately twice as long as the length of the core protruding from the cavity 7.

The present invention utilizes the above-mentioned mold to integrally configure the cavity 7 and the cavity part 12 by bringing the split 5 and the cavity mold 9 into contact with each other through a mold clamping operation, and the cavity part 1
With the tip of the small diameter portion 3 of the core 1 inserted into the cavity 7 without support, molten resin is injected and filled into the cavity 7 from a sprue bush (not shown) through the runner 13 and the gate 14, as shown in FIG. After molding the stepped hollow molded product 15, a small diameter portion I6 formed in the hollow portion 12 of the molded product 15 is formed.
is cut and removed flush with the end surface of the large diameter portion 17 formed in the cavity 7, thereby manufacturing the connector 18 shown in FIG.

(Function) The core 1 is placed in the center of the cavity 12 connected to the cavity 7.
Since the distal end of the core is inserted without support, the molten resin flows from the inside of the cavity 7 into the cavity 12 and flows toward the distal end of the small diameter core portion 3 during molding. A uniform and sufficient flow of resin can be obtained up to the connection surface between the cavity 7 side end face and the core small diameter part 3.
Unlike conventional methods, the end face of the large diameter part of the stepped hollow molded product 150 is molded accurately and neatly without insufficient inflow or unstable dimensions at the end of the resin flow, and the optical fiber insertion hole is formed by cutting. The durability of the part of the molded product 15 that becomes the opening is improved.

In addition, the small diameter portion 3 of the core 1 is held at the center of the cavity 12 and cooled and solidified due to the self-aligning effect due to the fluidity and orientation of the molten resin. The eccentricity is kept well below the allowable limit.

In addition, the final connector, which is the final product, can be produced by simply cutting and removing the small diameter part 16 of the molded product formed by the cavity part 12, which can be done with high accuracy without using a high-precision machine tool, and as described above. It is sufficient to cut it flush with the end face of the large diameter part of the molded product with good precision.

Therefore, a highly reliable connector 18 can be manufactured easily and efficiently.

(Effects of the Invention) As described above, according to the present invention, while using a mold that is simpler and easier to manufacture than in the past, the connection end can be finished accurately and neatly, and the opening of the optical fiber insertion hole can be made durable. To easily and efficiently manufacture a highly reliable connector with greatly improved performance.

[Brief explanation of drawings]

FIGS. 1 and 2 are a sectional view and an enlarged sectional view of essential parts of a mold for carrying out the method of the present invention. FIG. 3 shows a stepped hollow molded product manufactured by the method of the present invention, and FIG. 4 shows the same connector. FIGS. 5 and 6 are a sectional view and an enlarged sectional view of a main part of a mold for carrying out the conventional method, and an off view is a schematic diagram showing a conventional method of manufacturing a mold by electroforming. 1...Core, 2...Large diameter part, 3...Small diameter part, 4...
...Tapered portion, 5...Split, 6...Stripper, 7...Cavity, 8...Movable platen, 9...
...Cavity type, 10...Cavity insert,
11...Fixed platen, 12...Cavity part, 15...
- Stepped hollow molded product, 16... Small diameter part, 17... Large diameter part, 18... Connector. U) −”===ko

Claims (1)

[Claims] A stepped hollow molded product is produced by injection molding, etc. using a mold in which the small-diameter tip of a core supported and fixed in a cantilevered manner is inserted into the center of a cavity connected to the cavity. A method for manufacturing an optical fiber connector, comprising cutting and removing the cavity connecting portion of the molded product after manufacturing.