Method for manufacturing optical connector ferrule and optical connector ferrule

Abstract

This method for manufacturing an optical connector ferrule comprises preparing a mold for injection molding in which a groove is provided at a position that becomes the furthest downstream part of a resin in a space for forming the optical connector ferrule, forming a burr by discharging gas in the space from the groove and allowing a part of the resin to enter the groove when the resin is injected into the space, and removing the burr.

Description

Optical connector ferrule manufacturing method and optical connector ferrule

[0001] The present invention relates to a method for manufacturing an optical connector ferrule and an optical connector ferrule.This application claims priority to Japanese Patent Application No. 2024-146177, filed on August 28, 2024, the contents of which are incorporated herein by reference.

[0002] Optical connectors typically have a ferrule for positioning an optical fiber. The ferrule may be formed by injection molding. Patent Document 1 discloses a technology for an injection molding device for such optical components, in which the degree of vacuum within a heating barrel is set within a predetermined range to prevent gas from being compressed within the mold, thereby suppressing gas burns and other problems on the optical components.

[0003] Japanese Patent Application Publication No. 2010-105373

[0004] Adjusting the degree of vacuum as in Patent Document 1 makes the injection molding apparatus complicated. The inventors of the present application discovered that instead of adjusting the degree of vacuum, gas compression inside the mold can be prevented by devising the shape of the ferrule.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a method for manufacturing an optical connector ferrule that can suppress gas compression inside a mold during injection molding, and an optical connector ferrule.

[0006] In order to solve the above problem, a method for manufacturing an optical connector ferrule according to aspect 1 of the present invention includes preparing an injection molding mold having a space for forming the optical connector ferrule and having a groove at a position that is the most downstream part of the resin in the space, and when injecting the resin into the space, discharging gas in the space from the groove, and allowing a portion of the resin to enter the groove to form a burr, and then removing the burr.

[0007] The optical connector ferrule according to aspect 2 of the present invention may comprise a fiber hole through which an optical fiber is inserted, a connection end face into which the fiber hole opens, and a recess arranged along the outer periphery of the connection end face.

[0008] A third aspect of the present invention is the optical connector ferrule according to the second aspect, wherein the width of the recess may be 10 μm or more.

[0009] A fourth aspect of the present invention is the optical connector ferrule according to the second or third aspect, wherein the width of the recessed portion may be 500 μm or less.

[0010] A fourth aspect of the present invention is the optical connector ferrule according to any one of the second to fourth aspects, wherein the number of the recesses may be two or more.

[0011] According to the above aspects of the present invention, it is possible to provide an optical connector ferrule manufacturing method and an optical connector ferrule that can suppress gas compression inside a mold during injection molding.

[0012] 1 is a diagram showing an example of an optical connector equipped with a ferrule of the present embodiment. FIG. 2 is a cross-sectional view showing the structure of a mold for injection molding the ferrule of FIG. 1. FIG. 3 is a perspective view of the first member of FIG. 2. FIG. 4 is a view of a molded product molded by the mold of FIG. 1 as seen from the longitudinal direction. FIG. 5 is a view of the molded product of FIG. 4 as seen in the direction of an arrow V. FIG. 6 is a view of a ferrule obtained by removing burrs from the molded product of FIG. 4. FIG. 7 is a view of the ferrule of FIG. 6 as seen in the direction of an arrow VII.

[0013] An optical connector ferrule and a manufacturing method thereof according to the present embodiment will be described below with reference to the drawings. As shown in FIG. 1, an optical connector ferrule (hereinafter simply referred to as a ferrule 10) is used as a component of an optical connector 1. The optical connector 1 includes the ferrule 10, a housing 40, a boot 50, and a plurality of optical fibers F. The ferrule 10 has a plurality of fiber holes 11 and two positioning holes 12 formed therein. In this embodiment, the plurality of fiber holes 11 are arranged in a single row. However, the fiber holes 11 may also be arranged in multiple rows. Alternatively, the ferrule 10 may have only one fiber hole 11.

[0014] As shown in Figure 1, the ferrule 10 has a connection end face 10a. Fiber holes 11 and positioning holes 12 are opened in the connection end face 10a. An optical fiber F is inserted into each of the fiber holes 11. However, it is not necessary for an optical fiber F to be inserted into some of the fiber holes 11. In other words, the number of optical fibers F may be less than the number of fiber holes 11. The optical fibers F are exposed at the connection end face 10a. The connection end face of another connector to be connected can be abutted against the connection end face 10a, thereby optically connecting the optical connector 1 to the other connector.

[0015] (Direction Definition) In this specification, the direction in which the multiple fiber holes 11 extend is referred to as the longitudinal direction Z. The side of the connection end face 10a in the longitudinal direction Z (+Z side) is referred to as the front or tip side. The opposite side (-Z side) is referred to as the rear or base side. The direction in which the two positioning holes 12 are lined up is referred to as the first direction X. The first direction X is perpendicular to the longitudinal direction Z. One side in the first direction X is referred to as the +X side, and the other side is referred to as the -X side. The direction perpendicular to both the first direction X and the longitudinal direction Z is referred to as the second direction Y or the orthogonal direction. One side in the second direction Y is referred to as the +Y side, and the other side is referred to as the -Y side.

[0016] The two positioning holes 12 are arranged to sandwich the plurality of fiber holes 11 therebetween in the first direction X. The optical connector 1 of this embodiment is a male connector and has a positioning pin 17. The relative positions of the optical connector 1 and the other connector are determined by inserting the positioning pin 17 into the positioning hole of the other connector.

[0017] A portion of the ferrule 10 and a biasing member (not shown) are housed inside the housing 40. The tip end (the end on the +Z side) of the ferrule 10 protrudes from the housing 40. The ferrule 10 is biased toward the +Z side by the biasing member located inside the housing 40.

[0018] The ferrule 10 is made of resin and manufactured by injection molding. Fig. 2 is a schematic cross-sectional view of a mold 100 used for injection molding the ferrule 10. As shown in Fig. 2, the mold 100 has a first member 110, a second member 120, a third member 130, a fourth member 140, and an ejector pin EP. The mold 100 also has a plurality of pins (not shown) for forming the fiber holes 11 and the positioning holes 12.

[0019] The first member 110, the second member 120, the third member 130, and the fourth member 140 form a space S that corresponds to the outer shape of the ferrule 10. Molten resin flows into this space S, thereby injection-molding the ferrule 10.

[0020] The third member 130 has a slope 131. The slope 131 is a portion corresponding to the connecting end face 10a of the ferrule 10. The slope 131 is inclined toward the +Z side as it approaches the +Y side. Therefore, the connecting end face 10a is also inclined in the same manner.

[0021] As shown in Fig. 3, the first member 110 has an abutment surface 112, a main body forming surface 113, and a recess 114. The abutment surface 112 abuts against a sloped surface 131 of the third member 130. The abutment surface 112 is inclined like the sloped surface 131. A plurality of grooves 112a are formed in the abutment surface 112. The plurality of grooves 112a are arranged side by side in the first direction X. The recess 114 is recessed from the rear end of the main body forming surface 113. The recess 114 is a portion that forms the flange portion 14 of the main body of the ferrule 10 shown in Fig. 7.

[0022] (Manufacturing Method) Next, a method for manufacturing the ferrule 10 will be described. The manufacturing method of this embodiment includes a mold preparation step, a gas discharge step, a burr formation step, and a burr removal step. In the mold preparation step, a mold 100 is prepared. Note that the structure of the mold 100 shown in FIG. 2 is merely an example. The structure of the mold 100 may be changed as long as the groove 112a for discharging gas is provided.

[0023] Next, a gas discharge process is performed. In this gas discharge process, molten resin is poured into the space S. The resin inlet into the space S is located, for example, at the end on the -Z side of the space S. At this time, the resin flows in the +Z direction. That is, the vicinity of the connecting end face 10a is the most downstream portion of the resin flow. Here, the grooves 112a of the first member 110 are positioned at a position that corresponds to the most downstream portion of the resin. In this embodiment, the vicinity of the connecting end face 10a is the most downstream portion. More specifically, the grooves 112a are arranged side by side at positions corresponding to the outer periphery of the connecting end face 10a. Therefore, when the resin flows into the space S, the gas present in the space S passes through the grooves 112a and is discharged to the outside of the mold 100. That is, the grooves 112a are used as a gas discharge path.

[0024] In this way, by providing a gas exhaust path at the most downstream part of the resin, it is possible to prevent the gas from being compressed in the space S. This makes it possible to prevent problems that occur due to gas compression, such as gas burning and filling defects.

[0025] Next, a burr formation process is performed. In this burr formation process, burrs 15 are formed on the end surface 13 of the molded product 10', as shown in Figures 4 and 5. The burrs 15 are formed when the resin enters the grooves 112a of the mold 100. Therefore, the position, shape, number, etc. of the burrs 15 correspond to the grooves 112a. In this embodiment, the grooves 112a are formed on the abutment surface 112 that abuts against the inclined surface 131. Furthermore, the inclined surface 131 is a portion of the mold 100 that corresponds to the connecting end surface 10a of the ferrule 10. Therefore, the burrs 15 are arranged along the outer periphery of the connecting end surface 10a.

[0026] The width W of the burrs 15 in the first direction X shown in Fig. 4 is equal to the width W of the groove 112a shown in Fig. 3. The thickness T of the burrs 15 shown in Fig. 5 is equal to the depth of the groove 112a (the depth of the recess from the contact surface 112) shown in Fig. 3. The burrs 15 are formed side by side in the first direction X so as to follow the contour of the -Y side of the connecting end face 10a. The burrs 15 also protrude from the connecting end face 10a toward the -Y side.

[0027] In this embodiment, even after the space S is filled with resin, the resin continues to be injected into the space S. As a result, some of the resin enters the groove 112a, forming a burr 15. This ensures that the resin flows into the most downstream portion of the space S, stabilizing the flatness of the connection end face 10a. After the resin injection is complete, the resin is cooled and hardened. After the resin has hardened, the first member 110 is moved to the +Y side. At this time, the molded product 10' (see Figures 4 and 5) that will become the ferrule 10 is held by the fourth member 140.

[0028] Next, the ejector pin EP is protruded toward the +Y side relative to the fourth member 140. This removes the molded article 10' from the fourth member 140. The position of the burr 15 is preferably on the downstream side in the protruding direction of the ejector pin EP. If the burr 15 is located upstream in the protruding direction of the ejector pin EP (the -Y side in FIG. 2), the burr 15 is likely to break off and remain in the mold 100 when the molded article 10' is pressed. In this embodiment, the burr 15 is formed downstream in the protruding direction of the ejector pin EP (the +Y side). This prevents the burr 15 from breaking off and remaining in the mold 100.

[0029] Next, a burr removal process is performed. In the burr removal process, burrs 15 are removed from the molded product 10'. This results in the ferrule 10. As shown in Figures 6 and 7, multiple recesses 16 are formed in the ferrule 10. These recesses 16 are formed when the burrs 15 on the molded product 10' are removed, and some of the resin on the body side of the ferrule 10 peels off along with the base of the burr 15. Therefore, the position, number, and shape of the recesses 16 correspond to the position, number, and shape of the burrs 15. Specifically, the width W' of the recesses 16 in the first direction X is approximately equal to the width W of the burrs 15. The width T' of the recesses 16 in the longitudinal direction Z is approximately equal to the thickness T of the burrs 15.

[0030] The method for removing the burrs 15 is not particularly limited, but ultrasonic cleaning using water may be employed, for example. In this case, it is possible to remove the burrs 15 at the same time as removing impurities adhering to the molded product 10'. However, the burrs 15 may also be removed by methods other than cleaning, such as cutting or polishing.

[0031] Here, preferred dimensions of the groove 112a and the like will be described. The larger the cross-sectional area of ​​the groove 112a in the resin flow direction, the more reliably the gas in the space S can be discharged. However, the larger the dimensions of the groove 112a, the larger the burrs 15 on the molded product 10' and the recess 16 on the ferrule 10. If the recess 16 is too large, it may affect the appearance of the ferrule 10 and the connection performance of the optical connector 1 via the connection end face 10a. It is also possible to remove the recess 16 by a process such as polishing, but if the dimensions of the recess 16 are large, the polishing process takes time, leading to increased manufacturing costs.

[0032] In view of the above, it is preferable that the depth of the groove 112a, the thickness T of the burr 15, and the width T' of the recess 16 are 10 μm or more. Under these conditions, gas in the space S can be efficiently discharged. It is also preferable that the depth of the groove 112a, the thickness T of the burr 15, and the width T' of the recess 16 are 500 μm or less. Under these conditions, it is possible to remove the burr 15 by ultrasonic cleaning.

[0033] Furthermore, it is more preferable that the depth of the groove 112a, the thickness T of the burr 15, and the width T' of the recess 16 are 50 μm or less. Under these conditions, the burr 15 can be removed more easily and the influence of the recess 16 on the appearance can be suppressed. If the width T' of the recess 16 is 50 μm or less, the recess 16 can be removed in a short time by polishing the ferrule 10.

[0034] The width W of the groove 112a is not particularly limited, but is preferably 100 μm or more, for example. Under this condition, the groove 112a can be easily formed by cutting the first member 110, for example.

[0035] As described above, the manufacturing method for an optical connector ferrule according to this embodiment includes a mold preparation step, a gas discharge step, a burr formation step, and a burr removal step. In the mold preparation step, an injection molding mold 100 is prepared, which has a space S for forming the ferrule 10 and has a groove 112a formed at a position that corresponds to the most downstream portion of the resin in the space S. In the gas discharge step, gas within the space S is discharged from the groove 112a when resin is injected into the space S. In the burr formation step, a burr 15 is formed by allowing part of the resin to enter the groove 112a. In the burr removal step, the burr 15 is removed.

[0036] According to the manufacturing method of this embodiment, it is possible to suppress the compression of the gas within the space S of the mold 100. Therefore, it is possible to avoid the occurrence of gas burns, etc. Furthermore, compared to when the space S is evacuated, it is possible to simplify the device.

[0037] The optical connector ferrule of this embodiment comprises a fiber hole 11 through which an optical fiber F is inserted, a connection end face 10a into which the fiber hole 11 opens, and a recess 16 arranged along the outer periphery of the connection end face 10a.

[0038] The width T' of the recess may be 10 μm or more. In this case, by making the depth of the groove 112a in the mold 100 10 μm or more, gas within the space S of the mold 100 can be efficiently discharged.

[0039] The width T' of the recess may be 500 μm or less. In this case, since the thickness T of the burr 15 in the molded product 10′ is 500 μm or less, the burr 15 can be easily removed by, for example, ultrasonic cleaning.

[0040] The number of recesses 16 may be two or more. In this case, the mold 100 has a plurality of grooves 112a, which allows gas within the space S to be more reliably discharged.

[0041] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0042] For example, in the above embodiment, there are a plurality of grooves 112a in the mold 100, a plurality of flashes 15 in the molded product 10′, and a plurality of recesses 16 in the ferrule 10. However, the number of these may be one. As long as there is even one groove 112a, the effect of preventing gas burning can be obtained by discharging gas from the groove 112a.

[0043] The positions of the groove 112a, the burr 15, and the recess 16 may be changed. Even if the groove 112a is located in a place other than the outer periphery of the connecting end face 10a, the effect can be obtained as long as the groove 112a is located in the most downstream portion in the resin flow direction.

[0044] In addition, it is possible to replace the components in the above-described embodiments with well-known components as appropriate, and the above-described embodiments and variations may be combined as appropriate, without departing from the spirit of the present invention.

[0045] According to the above aspects of the present invention, it is possible to provide an optical connector ferrule manufacturing method and an optical connector ferrule that can suppress gas compression inside a mold during injection molding.

[0046] REFERENCE SIGNS LIST 1... Optical connector 10... Ferrule 10a... Connection end face 11... Fiber hole 15... Burr 16... Recess 100... Mold 112a... Groove F... Optical fiber

Claims

1. A method for manufacturing an optical connector ferrule, comprising: preparing an injection molding die having a space for forming an optical connector ferrule, the die having a groove formed at a position that will be the most downstream part of the resin in the space; discharging gas within the space from the groove when injecting the resin into the space; forming a burr by allowing part of the resin to enter the groove; and removing the burr.

2. An optical connector ferrule comprising: a fiber hole through which an optical fiber is inserted; a connection end face into which the fiber hole opens; and a recessed portion arranged along the outer periphery of the connection end face.

3. The optical connector ferrule according to claim 2, wherein the width of said recess is 10 μm or more.

4. An optical connector ferrule according to claim 2 or 3, wherein the width of the recess is 500 μm or less.

5. An optical connector ferrule according to any one of claims 2 to 4, wherein the number of said recesses is two or more.

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