JPH0899305A - Mold device for injection compression molding of ferrule - Google Patents

Abstract

PURPOSE: To improve dimensional accuracy, by a method wherein an effect of a compression process is made reliable when the ferrule is injection- compression-molded of ceramic powder containing a binder. CONSTITUTION: A movable retainer plate 66 has a hole part 71 forming the outer circumferential surface of a ferrule. A compression core pin 74 forming a tip surface of the ferrule is fitted slidably freely in an axial direction of the ferrule in a through hole 73 of a core insert 72 connecting with the hole part 71. A stationary mold 41 has a cavity pin 56 forming an end face of the opposite side and the inner circumferential surface of the ferrule. A ferrule forming surface 76 of the core pin 74 is in a planar state meeting at right angles with an axial direction of the ferrule and is equal with the whole of a projection of the axial direction of the ferrule. Hereby, an effect of compression is made to exhibit to the maximum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferrule injection compression molding die device for molding a ferrule molded body from a ceramic powder containing a binder.

[0002]

2. Description of the Related Art FIG. 6 shows a ferrule 1 used for holding and fixing an optical fiber in a plug. This ferrule 1 has a substantially cylindrical shape,
A tapered surface 3 is provided on the outer peripheral portion of the tip surface 2. Further, the through hole 4 in the ferrule 1 is a central needle hole, and the distal end portion is a small diameter portion 6 via a tapered portion 5.

The ferrule 1 is made of ceramics. In manufacturing the ceramic powder, a ceramic powder containing a binder is first injection-compressed and then the molded body is sintered.
At this time, the binder is removed. Then, if necessary, post-processing such as cutting is performed to improve accuracy.

An example (not known) of a conventional injection compression molding die apparatus used for manufacturing the ferrule 1 will be described with reference to FIG. In the figure, 11 is a fixed type and 12 is a movable type.
Move to the left and right in the figure to open and close each other, and when the mold is closed,
A cavity 13 in the shape of the ferrule 1 and a ring gate 14 leading to this cavity 13 are formed between each other. The fixed mold 11 includes a cavity pin 17 which forms one end surface and an inner peripheral surface of the ferrule 1 on a fixed side mold plate 16.
Is incorporated so that it can slide in the left-right direction. On the other hand, the movable die 12 has a movable side mold plate 22 having a hole portion 21 forming the outer peripheral surface of the ferrule 1, and the movable side mold plate 22 and the movable side receiving plate 23 fixed to the back surface thereof. The core insert 24 is fixed in between. The core insert 24 is provided for improving accuracy, and has a tapered surface 25 forming the tapered surface 2 of the ferrule 1 and a through hole 26 facing the tapered surface 25. And, in this through hole 26,
A core pin 27 forming the front end surface 2 of the ferrule 1 is fitted so as to be slidable in the left-right direction. In addition, this core pin 27
An insertion hole 28 into which the tip portion of the cavity pin 17 of the fixed mold 11 is inserted when the mold is closed is formed in this. The core insert 24 is also for improving gas venting, and has a slit for gas venting on the surface.

At the time of molding, a ceramic powder (hereinafter referred to as a molding material) containing a binder melted by heating is filled from the gate 14 into the cavity 13 in a mold closed state (filling step). After that, the core pin 27 located at the position shown by the solid line moves to the position shown by the chain line by t. As a result, the molding material in the cavity 13 is compressed (compression step). This compression step is for improving the dimensional accuracy of the ferrule 1. The compression allowance t is the ferrule 1
The total length is about 20 mm, while it is about 0.5 to 1 mm. Further, after the molding material in the cavity 13 is sufficiently solidified by cooling, the mold is opened. When the mold is opened, the cavity pin 17 first comes out of the through hole 4 of the ferrule (molded body) 1 in which the cavity pin 17 is molded. Then, the fixed mold plate 16 is separated from the molding material including the movable mold plate 22 and the ferrule 1 stopped on the movable mold 12 side. Further, the ferrule 1 is projected by the core pin 27 and comes out from the hole portion 21 of the movable side mold plate 22.

[0006]

However, the above-mentioned conventional mold device has a problem that sufficient dimensional accuracy cannot be ensured for the ferrule 1 at the molding stage. This is partly because the effect of the compression process is not sufficiently exerted. That is, the core pin 27 pushes only the front end surface 2 orthogonal to the axial direction of the ferrule 1, but there is a taper surface 3 on the outer peripheral side of the front end surface 2, and the front end surface 2 is the shaft of the ferrule 1. It only occupies part of the directional projection. Therefore, the compression effect by the core pin 27 is not sufficiently exerted. Moreover, since the through hole 4 of the ferrule 1 has the small diameter portion 6 on the core pin 27 side via the tapered portion 5, the compression effect by the core pin 27 is reduced by the resistance to the flow of the molding material. It stops around and does not reach the entire ferrule 1. Therefore, the molded ferrule 1
As shown in FIG. 5, the outer peripheral surface has a recessed shape around the tapered portion 5. As a result, the cylindricity D on the tip side of the outer peripheral surface of the ferrule 1 was about 10 μm, which was not satisfactory. In addition, the concentricity of the inner and outer peripheries of the ferrule 1 was not sufficient. As a result, post-processing such as cutting is required to ensure accuracy, but if high-accuracy post-processing is performed, the number of man-hours increases and productivity decreases.

Attempts have been made to increase the compression allowance t of the core pin 27 from 0.5 mm to 1 mm, but the effect was poor.

The present invention is intended to solve such a problem and provides a ferrule injection compression molding die device which can make the compression process effective and can improve the dimensional accuracy of the ferrule to be molded. The purpose is to provide.

[0009]

In order to achieve the above object, the present invention provides a ferrule injection compression molding die apparatus for molding a substantially cylindrical ferrule from a ceramic powder containing a binder. The mold member includes a plurality of mold members that open and close to form a cavity between the mold members when the mold is closed, and the mold member has a gate that communicates with one end of the cavity. A compression pin that forms an end face on the opposite side and is movable in the axial direction of the ferrule with respect to another mold member is provided, and the compression pin has a planar ferrule forming surface that is orthogonal to the axial direction of the ferrule, This ferrule forming surface is equal to the entire projection of the ferrule in the axial direction.

According to a second aspect of the invention, in the ferrule injection compression molding die device according to the first aspect of the invention, the through hole on the inner periphery of the ferrule has a distal end portion on the compression pin side having a diameter larger than that of other portions. It is small.

[0011]

In the ferrule injection compression molding die device of the present invention, at the time of molding, a ceramic powder containing a binder from a gate is formed in a cavity formed between a plurality of mold members closed. Material) and then a compression pin, which is a mold member forming an end surface of the ferrule opposite to the gate, is moved toward the gate in the axial direction of the ferrule to compress the molding material in the cavity. Further, after the molding material, that is, the ferrule in the cavity is sufficiently solidified, the mold is opened and the molded ferrule is taken out. In the compression pin, the planar ferrule forming surface orthogonal to the axial direction of the ferrule forms the end surface of the ferrule in the entire projection in the axial direction of the ferrule. Therefore, the effect of compression by the compression pin is maximized.

When the tip of the compression pin side of the through hole of the ferrule is smaller than the diameter of the other part in the ferrule injection compression molding die apparatus of the second aspect of the invention, As for the flow of the molding material from the compression pin side to the opposite side, the resistance increases at the large diameter part of the through hole, but as described above, the plane ferrule forming surface orthogonal to the ferrule axial direction is in the axial direction of the ferrule. By pushing the molding material over the entire projection, the effect of compression is obtained against said resistance.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a ferrule injection compression molding die apparatus of the present invention will be described below with reference to FIGS. FIG. 3 shows a ferrule (molded body) 31 to be molded. The ferrule 31 has a substantially cylindrical shape, and the tip surface 32 of the ferrule 31 has a ferrule 31.
It is orthogonal to the axial direction of and is equal to the entire projection of the ferrule 31 in the axial direction. Further, the through hole 34 in the ferrule 31 has a large diameter portion 35 on one end side and a small diameter portion 36 having a smaller diameter at the tip portion. Are connected by a tapered portion 37.

As shown in FIGS. 1 and 2, the mold apparatus comprises a fixed mold 41 and a movable mold 42 which move in the left-right direction in the drawing to open and close each other. These fixed type 41 and movable type 42
When the mold is closed, a pair of cavities 43 in the shape of the ferrule 31 (only one is shown), a ring gate 44 leading to one end (left end in the figure) of these cavities 43, and a runner 45 leading to these ring gates 44 are mutually connected. It is formed between them. The axial direction of the cavity 43, that is, the ferrule
The axial direction of 31 is the left-right direction, which coincides with the mold opening / closing direction.

The stationary die 41 has a stationary side mounting plate 52 which is mounted on a stationary side platen of an injection molding machine on the rear surface (left side in the drawing) of a stationary side mold plate 51 which is a mold member. The fixed side template 51 and the fixed side mounting plate 52 are
They move in the left-right direction and open and close each other. And, to these fixed side template 51 and fixed side mounting plate 52,
A sprue bush 53, to which the nozzle of the injection molding machine is connected, penetrates. The inside of the sprue bush 53 is a sprue 54 that communicates with the runner 45. And
The sprue bush 53 is fixed to the fixed side mounting plate 52 by a locate ring 55 fixed to the back side of the fixed side mounting plate 52. Further, the fixed die 41 is provided with a cavity pin 56 which is a die member. The cavity pin 56 is fixed to the fixed-side mounting plate 52 by sandwiching the flange portion 57 at one end thereof between the fixed-side mounting plate 52 and the locate ring 55. It can slide in any direction. Then, the cavity pin 56 has a step surface 58 that forms one end surface of the ferrule 31.
And a needle portion 59 forming the inner peripheral surface of the ferrule 31. This needle part 59 has a taper part 60 at the tip.
It has a small diameter portion 61 through.

In the movable die 42, a first movable side receiving plate 67 is fixed to the back surface (right side in the drawing) of a movable side die plate 66 which is a die member. Further, the second movable side receiving plate 68 is fixed to the rear side of the movable side receiving plate 67 via a spacer block 68, and the movable side platen of the injection molding machine is attached to the rear side of the second movable side receiving plate 68. The movable side mounting plate 70 that is mounted on is fixed. The movable-side template 66 has a hole 71 that forms the outer peripheral surface of the ferrule 31. A core insert 72, which is a mold member, is embedded on the back side of the movable side mold plate 66, and is pressed and fixed by the movable side receiving plate 67. The core insert 72 has a through hole 73 coaxially connected to the hole 71. Then, the core pin 74 as a compression pin penetrating the movable side receiving plate 67 is replaced with the core insert 72.
It is fitted in the through hole 73 of the so as to be slidable in the left-right direction. The core pin 74 forms the right end surface 32 of the ferrule 31, and has an insertion hole 75 formed in the front end portion into which the small diameter portion 61 of the cavity pin 56 is inserted when the mold is closed.
Then, the core pin 74 that forms the distal end surface 32 of the ferrule 31.
The ferrule forming surface 76 has a plane shape orthogonal to the axial direction of the ferrule 31, and is equal to the entire projection of the ferrule 31 in the axial direction.

Further, between the movable side receiving plates 67 and 69,
The protruding plate 81 is supported so as to be movable in the left-right direction.
To the protruding plate 81, protruding pins 82 and 83 are fixed, which penetrate the first movable side receiving plate 67 and the movable side mold plate 66 and have their tips facing the runner 45 or the sprue 54. Further, the return pin 84 also fixed to the protruding plate 81 penetrates the first movable side receiving plate 67 and the movable side mold plate 66. The return pin 84 has its tip abutted against the fixed-side mold plate 51 when the mold is closed. Further, a spring 85 is provided between the first movable side receiving plate 67 and the protruding plate 81 so as to surround the return pin 84.
The protruding plate 81 is biased by the direction 85 away from the first movable side receiving plate 67. Further, the core pin 74 is
Although penetrating the protruding plate 81, it is urged to the right side with respect to the protruding plate 81 by a spring 87 provided between the flange portion 86 formed at the right end of the core pin 74 and the protruding plate 81. There is.

A relay plate 91 is provided so as to penetrate the second movable side receiving plate 69. The relay plate 91 has a flange portion 92 at the left end, and when the mold is closed, the flange portion 92 can move in the left-right direction between the second movable-side receiving plate 69 and the protruding plate 81 as much as allowed. It has become. In addition,
The relay plate 91 is retained by the bolt 93 with respect to the protruding plate 81. Further, a hydraulic cylinder 94 is provided in the movable side mounting plate 70. This hydraulic cylinder
The piston rod 95 of 94 moves in the left-right direction and pushes the relay plate 91 to the left. The second movable side receiving plate
The stroke T of the piston rod 95 is restricted by the stopper 96 fixed to the back surface of the 69. A receiving pin 97 fixed to the protruding plate 81 penetrates the relay plate 91 and the piston rod 95. The receiving pin 97 is pushed by an ejection rod 98 provided in the injection molding machine.

Next, the operation of the above configuration will be described. At the time of molding, the mold is first closed as shown by the solid line in FIGS. In this state, the fixed mold plate 51, the cavity pin 56, the movable mold plate 66, the core insert 72 and the core pin.
Cavity 43 is formed between 74 and fixed side template
A runner 45 and a ring gate 44 are formed between the 51 and the movable side template 66. Then, the ceramic powder (hereinafter referred to as a molding material) containing the binder melted by heating is injected into the sprue 54 from the nozzle of the injection molding machine. Molding material flows from the gate 44 through the runner 45 to the cavity
It is filled in 43 (filling process).

After this filling step, the piston rod 95 of the hydraulic cylinder 94 moves to the left, that is, toward the fixed die 41.
Pushed by the piston rod 95, the relay plate 91 and the core pin 74 also move with respect to the movable receiving plates 67 and 69 and the ejecting plate 81. The relay plate 91 moves until it abuts against the ejection plate 81, and therefore the core pin 74 also moves to a predetermined position with respect to the movable side mold plate 66 and the core insert 72, as shown by the chain line in FIG. Thus, the tip surface of ferrule 31
The molding material in the cavity 43 is compressed by the core pin 74 forming 32 moving in the axial direction of the ferrule 31 toward the gate 44 by the compression margin T (compression step).

Further, after the molding material in the cavity 43, that is, the ferrule 31 is sufficiently solidified by cooling, the mold is opened. When the mold is opened, first, the first parting line PL1 between the fixed side mounting plate 52 and the fixed side mold plate 51 is opened. As a result, the cavity pin 56 is completely removed from the through hole 34 of the molded ferrule 31. Next, the second parting line PL2 between the fixed-side mold plate 51 and the movable-side mold plate 66 is opened.
Along with this, the molding material solidified in the sprue 54, the runner 45, and the ring gate 44 separates from the fixed-side template 51.
Next, when the ejecting rod 98 pushes the receiving pin 97, the ejecting plate 81 moves, and the ejecting pins 82 and 82 eject the molding material solidified in the sprue 54, the runner 45 and the ring gate 44 to move the movable side mold plate. Release from 66. Along with this, the relay plate 91 and the core pin 74 also move integrally with the protruding plate 81, and are pushed by the core pin 74, and the ferrule 31 is pulled out from the hole portion 71 of the movable side mold plate 66.
Further, the molding material solidified in the sprue 54 and the ferrule 31 are taken out.

Thereafter, the mold is closed again, and the above molding cycle is repeated. When closing the mold, together with the spring 85,
The fixed-side mold plate 51 pushes the protruding plate 81 via the return pin 84, whereby the protruding plate 81 returns to the position shown in FIG. Further, the piston rod 95 of the hydraulic cylinder 94 moves in the direction away from the fixed die 41, and
When pushed by 87, the core pin 74 and the relay plate 91 also move in the same direction. The relay plate 91 moves until its flange portion 92 abuts on the second movable side receiving plate 67, and thus the core pin 74 also moves to a predetermined position with respect to the movable side mold plate 66 and the core insert 72. Further, as the fixed side mold plate 51 and the fixed side mounting plate 52 are closed, the needle part 59 of the cavity pin 56 is inserted into the hole part 71 of the movable side mold plate 66, and the diameter of the needle part 59 is small. The part 61 is the insertion hole 75 of the core pin 74.
Fit inside.

The ferrule 31 which is a molded body molded as described above is further sintered. At this time, the binder is removed. Then, if necessary, post-processing such as cutting is performed.

As described above, the cavity 43 is filled after the filling process.
The core pin 74 that compresses the molding material inside has the ferrule forming surface 76 that forms the distal end surface 32 of the ferrule 31.
The ferrule has a planar shape that is orthogonal to the axial direction of the ferrule.
The compression effect by the core pin 74 will be maximized since it is equal to the entire 31 axial projection. In particular, the ferrule 31 of the above-described embodiment has the small diameter portion 36 at the tip of the through hole 34 on the inner periphery thereof.
During the compression process, the flow of the molding material from the core pin 74 toward the gate 44 in the cavity 43 is the cavity pin 56.
Although the resistance increases after the tapered portion 60 of the, as described above, the planar ferrule forming surface 76 orthogonal to the axial direction of the ferrule 31 pushes the molding material in the entire projection of the ferrule 31 in the axial direction. The compression effect is reliably obtained against the resistance.

By making the compression process effective in this way, the dimensional accuracy of the ferrule 31 to be molded, that is, the cylindricity of the outer peripheral surface of the ferrule 31 and the concentricity of the inner and outer peripheries of the ferrule 31 can be increased. As a result, it becomes unnecessary to machine the outer peripheral surface of the ferrule 31 after molding, such as cutting, which requires high precision, and the number of steps can be reduced and the productivity can be improved.

If the tapered surface 3 as shown in FIG. 6 is required at the tip of the ferrule 31, it can be formed by post-processing such as cutting.

Furthermore, the present invention is not limited to the above embodiment, but various modifications can be made. For example, the shape of the ferrule is not limited to that of the above embodiment,
For example, the inner diameter may be constant over the entire length. Further, the structure of the mold device is not limited to that of the above embodiment. For example, the drive source of the core pin is not limited to the hydraulic cylinder incorporated in the mold apparatus as in the above-described embodiment, but may be one provided on the molding machine side.

[0028]

According to the invention of claim 1, the compression pin which forms the end face of the ferrule and is movable in the axial direction of the ferrule with respect to the other mold members has a planar shape orthogonal to the axial direction of the ferrule. It has a ferrule forming surface, and this ferrule forming surface is the same as the entire projection of the ferrule in the axial direction. Therefore, when the molding material filled in the cavity is compressed by the compression pin, this compression effect is maximized. ,
Therefore, the dimensional accuracy of the molded ferrule can be improved.

According to the second aspect of the present invention, the compression step can be made effective even if the tip of the compression pin side in the through hole of the ferrule has a smaller diameter than the other portions.

[Brief description of drawings]

FIG. 1 is a partial enlarged cross-sectional view showing an embodiment of a ferrule injection compression molding die apparatus of the present invention.

FIG. 2 is a cross-sectional view of almost the same as above, and the cross-sectional positions are different on both sides of the center line (one-dot chain line).

FIG. 3 is a cross-sectional view of a ferrule molded by the same as above.

FIG. 4 is a sectional view showing an example of a conventional injection compression molding die device for a ferrule.

FIG. 5 is a cross-sectional view showing the same problem.

FIG. 6 is a sectional view of a ferrule.

[Explanation of symbols]

 31 Ferrule 32 Tip surface (end surface opposite the gate) 34 Through hole 43 Cavity 44 Ring gate (gate) 51 Fixed side mold plate (mold member) 56 Cavity pin (mold member) 66 Movable side mold plate (mold) Parts) 72 Core insert (mold member) 74 Core pin (mold member, compression pin) 76 Ferrule forming surface

Claims (2)

[Claims] 1. A mold device for injection compression molding of a ferrule for molding a substantially cylindrical ferrule from a ceramic powder containing a binder, comprising a plurality of mold members that are opened and closed to form a cavity between them when the mold is closed. Along with this mold member, a gate communicating with one end of the cavity is formed, and in the mold member, an end surface of the ferrule opposite to the gate is formed, and an axial direction of the ferrule with respect to other mold members is formed. Equipped with a movable compression pin,
This compression pin has a planar ferrule forming surface that is orthogonal to the axial direction of the ferrule, and this ferrule forming surface is
A mold device for injection compression molding of a ferrule, characterized in that it is made equal to the entire projection of the ferrule in the axial direction. 2. The injection compression molding gold for a ferrule according to claim 1, wherein the through hole in the inner circumference of the ferrule has a tip end portion on the compression pin side having a smaller diameter than other portions. Mold device.