JPH0952258A - Mold device for injection molding and manufacture of cylindrical molding having slender through hole by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection mold capable of improving the inserting accuracy of a core pin to form a slender through hole of a molding and preventing the damage of the pin and a method for manufacturing the molding by using the same. SOLUTION: A sleeve pin 5 capable of being axially reciprocated is provided in the insert block 4 of a movable side mold plate 1. A core pin 6 is so contained in the piston 5 as to be able to axially move in the piston 5. The end of the needle 61 of the pin is held in the end pore of the protruding rod block 62 of the piston 5. At the time of clamping the mold, the end of the needle 61 is inserted into the guide protrusion 32 of a stationary side mold plate 3. The piston 5 is retracted in this state to form a cavity, and resin is filled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device for injection-molding a cylindrical molded body having a fine through hole and a method for producing a cylindrical molded body having a fine through hole using the same. A specific example of a cylindrical molded body having a thin through hole is a ferrule that guides an optical fiber used in optical communication to an optical connector.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 04-041215 discloses a technique for molding a ferrule by holding a core pin on a stationary mold plate. However, as far as the inventors of the present invention have investigated, the ferrule manufactured based on this technique is not commercially available. Further, the technique has the following problems.

1. Since the distance from the support point of the core pin to the tip of the core pin is long, the insertion of the tip into the movable mold plate becomes unstable. In order to carry out this stably, it is necessary to secure a large clearance at the insertion portion, and in this case, the molding accuracy of the molded body deteriorates. This is because the distance from the support point of the core pin to the tip end of the core pin becomes longer, so that the bending of the core pin due to its own weight increases. 2. When the molded body is ejected from the mold after the molding is completed, it is necessary to open the PL surface largely so that the core pin and the molded body do not come into contact with each other. 3. The core pin projects from the fixed-side template, so the handleability of the core pin is poor. This is because the core pin is very thin and easily broken. 4. At the moment when the fixed side mold plate and the movable side mold plate are opened, if there is a slight deviation, the core pin will break. This is also because the core pin is very thin and easily broken.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an injection molding die apparatus capable of solving the above-mentioned problems and a method for producing a cylindrical molded body having a fine through hole using the same. Especially.

[0005]

Means for Solving the Problems The inventors of the present invention have made earnest studies to achieve the above-mentioned object, and as a result, after accurately positioning the fixed-side mold plate and the movable-side mold plate during mold clamping, The core pin held by the plate is moved toward the fixed-side mold plate, and the tip of the needle part is inserted into the guide hole of the guide protrusion of the fixed-side mold plate to stably hold the needle part and perform resin injection. At the same time, they have found that it is sufficient to hold the tip of the needle portion at a fixed position in the cavity even during the protruding operation of the molded body, and complete the present invention.

That is, an injection molding die apparatus for injection molding a cylindrical molded body having a thin through hole according to the present invention,
A fixed-side mold plate (3) having a resin injection port (34) and a movable-side mold plate (1) that can be moved toward and away from the fixed-side mold plate (3) in the axial direction are provided. A taper surface (311) is provided on one of the fixed-side mold plate (3) and the movable-side mold plate (1) so as to ensure accurate positioning of the fixed-side mold plate (3) and the movable-side mold plate (1). A convex part (31) having is formed, and the other has a tapered surface (111) corresponding to the convex part.
And a movable side template (1) in which a recess (110) having
A sleeve piston (5), which is axially movable, is housed in a nesting block (4) fixed inside the sleeve.
At the tip of the sleeve piston (5), the fixed side template (3)
A protruding rod portion (51) is formed which is inserted into the cavity forming hole (40) formed in the nesting block (4) so as to open toward the inner side of the sleeve block (4).
A core pin (6) that can be moved in the axial direction is accommodated,
The leading rod portion (61) of the core pin (6) is inserted into the central hole of the protruding rod portion (51) of the sleeve piston (5), and the needle portion (62) is provided at the tip of the leading rod portion (61). The needle portion (62) is formed, and the tip of the needle portion (62) is inserted into the pore of the tip of the protruding rod portion (51) of the sleeve piston, and the core pin (6) is inserted in the sleeve piston (5).
Is moved toward the fixed side template (3), the needle (6
The tip of 2) is the tip pore (5) of the protruding rod portion (51).
2) through the parting surface (PL1) of the movable side mold plate, and the fixed side mold plate (3) has a protruding rod portion (5) of the sleeve piston (5) at the time of mold clamping. A guide convex portion (32) having a guide hole (321) for receiving the tip of the needle portion (62) of the core pin (6) protruding from the parting surface (PL1) of the movable side template through the tip fine hole (52) of 51). ) Is provided, the movable side mold plate (1), the sleeve piston (5),
A drive mechanism that allows the core pin (6) and the ejector pin (10) to reciprocate individually toward the fixed-side mold plate (3) and a control device for the drive mechanism are provided. After advancing toward the fixed-side mold plate (3) and inserting the tip of the needle portion (62) into the guide hole (321) of the guide convex portion (32) of the fixed-side mold plate (3), that state When the sleeve piston (5) is retracted for a predetermined distance while maintaining the above condition, the protruding rod portion (51) of the sleeve piston (5) is retracted within the cavity forming hole (40) of the nesting block (4) for a predetermined distance. Cavity (41) is formed by the above, resin is injected in the state where the needle portion (62) of the core pin (6) is present in the cavity (41), and after the resin is cured, the core pin (6) is Of the needle part (61) The end is pulled out from the guide hole (321) of the guide convex portion (32) of the fixed side template (3) and is retracted until it returns to near the parting surface (PL1) of the movable side template, and the mold is opened. , The ejector pin (10) and the sleeve piston (5) are moved toward the stationary mold plate (3) to project the molded body (41 ′), so that the thin needle portion (62) of the core pin (6) is It is characterized in that a cylindrical molded body having a through hole having an inner diameter equal to the diameter is obtained. In addition,
The numbers in parentheses indicate the reference numbers in the figure of each component in the illustrated embodiment.

The present invention also relates to a method for producing a cylindrical molded body having a narrow through hole by using the above-mentioned injection molding die device, in which the movable side mold plate (1) is directed to the fixed side mold plate (3). The movable side mold plate (1) while fitting the positioning convex portion (31) and the concave portion (110) provided on the both sides.
And a small clearance (C) between the fixed side template (3)
And the core pin (6) is advanced toward the fixed mold plate (3) so that the tip of the needle portion (62) guides the fixed mold plate (3). Convex part (3
2) The step of performing the second mold clamping into the guide hole (321), and the sleeve piston (5) is retracted by a predetermined distance, and the cavity forming hole (4) of the nesting block (4) is formed.
0) in which the protruding rod portion (51) of the sleeve piston (5) is retracted by a predetermined distance to form the cavity (41), and the sleeve piston (5) is appropriately reciprocated to move the cavity (41) The step of injecting the resin into the cavity (41) while keeping the internal pressure constant, the step of curing the injected resin, and the step of curing the resin after the core pin (6) is fixed to the needle portion (6
The tip of 1) is the guide convex portion (32) of the fixed side template (3).
Of the movable side mold plate (1) is pulled out from the guide hole (321) of the movable side mold plate and returned to near the parting surface (PL1) of the movable side mold plate, and the movable side mold plate (1) is separated from the fixed side mold plate (3) to open the mold. Step and ejector pin (1
0) and the sleeve piston (5) are moved toward the fixed-side mold plate (3) to eject the molded body (41 ′).

An example of the cylindrical molded body having the thin through hole is a ferrule for an optical fiber, in which case the diameter of the thin needle portion (62) of the core pin is 20.
It is recommended that the thickness be 0 μm or less.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a state immediately after a molded body is ejected from a mold in an embodiment of an injection molding mold device according to the present invention. The sleeve piston 5 and the ejector pin 10 provided on the movable mold plate 1 are in a state of being pushed out to the front of the mold. The sleeve piston 5 is pushed out by a hydraulic cylinder (not shown).

FIG. 2 is a cross-sectional view of the mold device in the first mold clamped state. The movable side mold plate 1 is pushed out by the receiving plate 2 and the parting surface (PL1 surface) is tightened. Tapered surfaces 311 and 111 are formed on the convex portion 31 of the fixed-side mold plate 3 and the concave portion 110 of the movable-side mold plate 1, respectively, and are formed on the fixed-side mold plate 3 and the movable-side mold plate 1 simultaneously with the first mold clamping. The positioning with the nesting block 4 fitted therein is performed accurately. If the first mold clamping is performed without performing the positioning using the taper, the positioning accuracy between the fixed-side mold plate 3 and the nesting block 4 fitted in the movable-side mold plate 1 cannot be obtained. The core pin may be damaged during insertion.
Further, if the core pin is to be inserted without the accuracy being obtained, it is necessary to make the hole diameter of the fine hole 52 large, and the coaxial accuracy cannot be obtained. Simultaneously with the first mold clamping, the sleeve piston 5 is pushed backward by the distance Y by the slide adjusting pin 33 provided so as to project from the fixed mold plate 3. Further, there is a clearance C between the parting surfaces (PL1 surfaces) of the fixed mold plate 3 and the movable mold plate 1, and only the tapered surfaces 311 and 111 are contact surfaces.
A coil spring 8 is provided between the movable side mold plate 1 and the receiving plate 2.
Since a is arranged, the parting surfaces (PL2 surfaces) of the movable side mold plate 1 and the receiving plate 2 are not clamped at this stage of mold clamping (shown in FIG. 1). In this state, the tip end of the needle portion 62 of the core pin 6 is in a state of being inserted and held in the pore 52 (enlarged and shown in FIG. 6) of the tip end of the protruding rod portion 51 of the sleeve piston 5, Fixed side template 3
Has not reached the guide protrusion 32.

FIG. 3 is a cross-sectional view of the mold device in the second clamped state. At this stage, the receiving plate 2 is the movable mold plate 1
The parting surface (shown as PL2 in FIG. 1) is tightened by moving a distance X toward and pressing. By this operation, the core pin 6 is pushed out by the distance X, and the tip of the needle portion 62 of the core pin is inserted into the guide hole 321 (enlarged and shown in FIG. 6) of the guide convex portion 32 of the fixed side template 3. . At that time, since the needle portion 62 of the core pin 6 is held by the tip end hole of the protruding rod portion 51 of the sleeve piston 5, the tip portion of the needle portion 62 is accurately inserted without bending. Then, the resin inflow space (cavity) 41 is formed by retracting only the sleeve piston 5 by a hydraulic cylinder (not shown) by a distance Z (see FIGS. 4, 5 and FIG. 6 which is an enlarged view thereof). It

FIG. 4 is a sectional view of the mold apparatus in a state after completion of injection. Resin is injected from the resin injection port 34 of the fixed-side mold plate 3, and at the same time when the resin is injected, the internal pressure in the cavity 41 is kept constant by the cylinder via the sleeve piston 5. At the same time when the injection of the resin is completed and the resin is filled in the cavity 41, the sleeve piston 5 is pushed out by the hydraulic cylinder at a constant pressure. By this operation, the internal pressure of the tree cavity 41 can be kept constant. Further, it becomes possible to reduce the shrinkage of the resin in the cavity 41, and it is possible to improve the accuracy of cylindricity and coaxiality of the molded body 41 '. Examples of the resin used for ferrule production include polyethersulfone PE
S, polyetheretherketone PEEK, polyphenylene sulfide PPS, liquid crystal polymer, and the like.

FIG. 5 is a sectional view of the mold apparatus in a state where the second mold clamping is released. FIG. 6 is an enlarged cross-sectional view of an essential part showing the configuration of each part centering on the resin injection part, and FIG. 7 shows the state of the tip of the needle portion and the molded body during the conventional protruding operation of the molded body. It is explanatory drawing compared with that of invention. After the resin is cured, the receiving plate 2 retracts, the parting surface (PL2 surface) opens, and at the same time, the core pin 6 retracts due to the restoring force of the coil spring 8b. At this time, the tip end of the needle portion 62 of the core pin is pulled out from the guide convex portion 32 of the fixed-side template 3 and is retracted to the end face position of the nesting block 4 or slightly inside thereof. After that, the receiving plate 2 is further retracted, the parting surfaces (PL1 surfaces) of the fixed mold plate 3 and the movable mold plate 1 are opened (shown in FIG. 1), and the first mold clamping is released. Next, the sleeve piston 5 and the ejector pin 10 are simultaneously advanced to eject the molded body 41 'from the mold.

When the molded body 41 'is ejected, the tip of the needle portion 62 may be bent due to the weight of the protruding molded body 41' as shown in FIG. 7 (A). There were many. On the other hand, in the present invention, as shown in FIG. 7 (B), since the tip of the needle portion 62 does not protrude from the end surface of the nesting block 4, the molded body 4 that is ejected.
The tip of the needle portion 62 is not bent by the weight of 1 '. Furthermore, in the present invention, the molded body 41 ′ is simultaneously projected not only by the ejector pin 10 but also by the projecting rod portion 51 of the sleeve piston 5,
At this time, the needle portion 62 is stably held in the projecting rod portion 51, and the tip of the needle portion 62 is held in the tip pore of the projecting rod portion 51. It is not affected at all, and the tip of the needle portion 62 is not bent or damaged.

[0015]

EXAMPLE FIG. 8 is a diagram showing the change over time in the cavity internal pressure when injection molding a cylindrical molded body having a thin through hole using the injection molding die apparatus according to the present invention. Polyphenylene sulfide PPS was used as the resin.
The molding temperature was 330 ° C. and the molding pressure was 70 kg / cm ² . The sleeve piston 5 is axially reciprocated by a hydraulic cylinder (not shown). During molding, the servo valve controls the hydraulic pressure in multiple stages to directly control the cavity internal pressure. The change over time in the cavity internal pressure due to the conventional molding method is shown by the broken line, and the change over time in the cavity internal pressure of the present invention is shown by the solid line. In the present invention, the pressure inside the cavity is made uniform, and the cylindricity of the molded product is improved. Further, in the present invention, the peak pressure of the cavity internal pressure is prevented, and the concentricity of the molded product is improved. According to the present invention, it is possible to mold a molded body having a diameter of a maximum of 200 μm in a cylindrical molded body having a thin through hole.

[0016]

By using the mold device of the present invention, (1) the handling of the core pin is improved, (2) the core pin insertion accuracy is improved, and (3) the weight of the molded body is not applied to the core pin. So the core pin will not break,
(4) Many effects can be expected, such as the possibility that the core pin will not be broken even if a slight deviation occurs at the moment when the fixed-side template and the movable-side template are opened. The cylindrical molded body having a thin through hole manufactured by the manufacturing method of the present invention has, for example, a diameter of 5
mm x length 12 mm, pore diameter at the center of the cylinder is 127 μm
And the tolerance can be manufactured on the order of microns. Further, according to the mold apparatus and the manufacturing method of the present invention, it is possible to provide a molded product that can sufficiently withstand severe conditions in the field of optical communication.

It should be noted that the present invention is not limited to the above-described embodiments, but encompasses all modified embodiments that can be easily conceived by those skilled in the art from the above description within the scope of the present invention. It is.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state immediately after a molded body is ejected from a mold in an embodiment of an injection molding mold device according to the present invention.

FIG. 2 is a cross-sectional view of the mold device in a first clamped state.

FIG. 3 is a cross-sectional view of the mold device in the second clamped state.

FIG. 4 is a cross-sectional view of the mold device in a state after completion of injection.

FIG. 5 is a cross-sectional view of the mold device in a state after the second mold clamping is released.

FIG. 6 is an enlarged cross-sectional view of an essential part showing the configuration of each part centering on a resin injection part.

FIG. 7 is an explanatory view for comparing the state of the tip of the needle portion and the molded body during the conventional protruding operation of the molded body with that of the present invention.

FIG. 8 is a diagram showing changes with time in cavity internal pressure during injection molding of a cylindrical molded body having a thin through hole.

[Explanation of symbols]

 1 Movable side mold plate 2 Receiving plate 3 Fixed side mold plate 31 Convex part 311 Tapered surface 32 Guide convex part 321 Guide guide 33 Slide adjustment pin 4 Nesting block 40 Cavity forming hole 41 Cavity 41 'Molded body 5 Sleeve piston 51 Projecting rod part 52 Tip hole 6 Core pin 61 Lead rod part 62 Needle part 7 Ball slider 8a, 8b Coil spring 9 Guide pin 10 Ejector pin 110 Recessed part 111 Tapered surface PL1,2 Parting surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hagiwara ▲ Taku ▼ 2-1, 1-1 Tangodori, Minami-ku, Aichi Prefecture Nagoya Mitsui Toatsu Chemical Co., Ltd.

Claims (4)

[Claims] 1. A mold apparatus for injection molding for injection molding a cylindrical molded body having a thin through hole, wherein a fixed side template (3) having a resin injection port (34) and a fixed side template (3). ) And a movable side mold plate (1) that can be moved toward and away from each other in the axial direction so as to ensure accurate positioning of the fixed side mold plate (3) and the movable side mold plate (1) during mold clamping. As described above, the convex portion (31) having the tapered surface (311) is formed on one of the fixed side mold plate (3) and the movable side mold plate (1), and the tapered surface (111) corresponding to the convex part is formed on the other side. ) Having a recessed portion (110) formed therein, the nesting block (4) fixed in the movable side template (1).
A sleeve piston (5) that can be moved in the axial direction is accommodated therein, and the stationary side template (3) is provided at the tip of the sleeve piston (5).
A protruding rod portion (51) is formed which is inserted into the cavity forming hole (40) formed in the nesting block (4) so as to face the opening and is moved in the sleeve piston (5) in the axial direction. The core pin (6) is accommodated, the leading rod portion (61) of the core pin (6) is inserted into the center hole of the protruding rod portion (51) of the sleeve piston (5), and the tip end of the leading rod portion (61) is inserted. A needle portion (62) is formed in the sleeve, and the tip of the needle portion (62) is inserted into the pore of the tip of the protruding rod portion (51) of the sleeve piston, and the core pin (6) is inserted in the sleeve piston (5).
Is moved toward the fixed side template (3), the needle (6
The tip of 2) is the tip pore (5) of the protruding rod portion (51).
2) is configured to project from the parting surface (PL1) of the movable side mold plate by a predetermined length, and the fixed side mold plate (3) has a protruding rod portion (5) of the sleeve piston (5) at the time of mold clamping. A guide convex portion (32) having a guide hole (321) for receiving the tip of the needle portion (62) of the core pin (6) protruding from the parting surface (PL1) of the movable side template through the tip fine hole (52) of 51). ) Is provided, and the movable side mold plate (1), the sleeve piston (5), the core pin (6) and the ejector pin (10) can be individually reciprocated toward the fixed side mold plate (3). A mechanism and a control device therefor are provided, and in the mold clamping state, the core pin (6) is advanced toward the fixed-side mold plate (3), and the tip of the needle portion (62) is fixed-side mold plate (3). The above-mentioned guide protrusion (32) Guide holes (3
21) and then retracting the sleeve piston (5) for a predetermined distance while maintaining that state, the protruding rod portion (5) of the sleeve piston (5) is moved within the cavity forming hole (40) of the nesting block (4). 51) retreats a predetermined distance,
Thereby, a cavity (41) is formed, resin is injected in a state where the needle portion (62) of the core pin (6) is present in the cavity (41), and after the resin is cured,
The tip of the needle portion (61) of the core pin (6) is pulled out from the guide hole (321) of the guide convex portion (32) of the fixed side mold plate (3) and near the parting surface (PL1) of the movable side mold plate. Retreat until it returns to, and open the mold,
The ejector pin (10) and the sleeve piston (5) are moved toward the stationary mold plate (3) to form the molded body (41 ').
And a cylindrical molded body having a through hole having an inner diameter equal to the diameter of the thin needle portion (62) of the core pin (6). . 2. A thin needle portion (6) of the core pin (6).
The mold apparatus for injection molding according to claim 1, wherein the diameter of 2) is 200 μm or less. 3. A method for producing a cylindrical molded body having a thin through hole by using the injection molding die apparatus according to claim 1, wherein the movable side mold plate (1) is fixed to the fixed side mold plate (3). And the positioning projections (31) and the recesses (11) provided on both of them.
0) are fitted and the first mold clamping is performed so that a slight clearance (C) is formed between the movable side mold plate (1) and the fixed side mold plate (3), and the core pin (6). ) Toward the fixed-side template (3),
The step of inserting the second end of the needle portion (62) into the guide hole (321) of the guide protrusion (32) of the fixed-side die plate (3), and the sleeve piston (5) are retracted by a predetermined distance. Forming a cavity (41) by retracting the protruding rod portion (51) of the sleeve piston (5) within the cavity forming hole (40) of the nesting block (4) by a predetermined distance. ) Is appropriately moved back and forth to inject the resin into the cavity (41) while keeping the internal pressure of the cavity (41) constant, to cure the injected resin, and after the resin is cured, the core pin ( 6) the needle part (61)
The front end of the movable side mold plate (3) is pulled out from the guide hole (321) of the guide protrusion (32) of the fixed side mold plate (3) and returned to near the parting surface (PL1) of the movable side mold plate, and A step of separating the plate (1) from the stationary mold plate (3) to open the mold, and moving the ejector pin (10) and the sleeve piston (5) toward the stationary mold plate (3) to form a molded body ( 41 ')
A method for manufacturing a cylindrical molded body having a thin through hole, characterized in that: 4. The method for producing a cylindrical molded body having a thin through hole according to claim 3, wherein the cylindrical molded body is a ferrule for an optical fiber.