JPS61249714A - Mold - Google Patents

Abstract

PURPOSE:To reduce the irregularity of the small hole-diameter and the outline dimension of this part in a molded product, and moreover to decrease the roughness of the outline surface of the tip of the molded product, and then to prevent the lowering of the mechanical strength of said tip part by moving a core pin sleeve upward by the pressure of the molding molten material flowing into from a sprue at molding. CONSTITUTION:The liquid surface of molding molten material 70 rises gradually, and a core pin sleeve driving member 62 moves upward against the pushing force of a spring 63 with said surface rise. The core pin sleeve 60 connected by a linking member 61 moves upward gradually with the above mentioned upward movement. Because a part of the molding molten material 70 staying for a long time in a cylinder long in said material 70 coming into a problem in relation to the ferrule becoming a product finally, flows at the position apart from the bottom (the projected part of a minute pin 55) of a product molding cavity, the irregularity of the small hole diameter of the ferrule is reduced, and moreover the roughness of the outline surface of the ferrule tip is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a molding die used, for example, in molding a ferrule of an optical fiber plastic connector (hereinafter referred to as an optical connector).

[Technical background of the invention and its problems] As shown in FIG. 3 as an example of a conventional optical connector, there is a hole 2 into which an optical fiber core 1 is inserted, and a hole with a diameter of, for example, 125 μm into which an optical fiber 3 is inserted. It is composed of a ferrule 5 having a minute hole 4, a sleeve 6 provided around the outer periphery of the ferrule 5, and a cap nut 7 that connects the sleeve 6 and the sleeve 6 and the ferrule 5.

The ferrule 5 is molded using a molding die comprised of a fixed die 10 and a movable die 20, as shown in FIG.

The fixed mold 10 has a molding resin injection port 11 and a guide hole 12.
The fixed mold main body 14 has a core pin insertion hole 13, and the core pin 15 is inserted and fixed into the Abin insertion hole 13 of the fixed mold main body 14 and has a micro pin insertion hole 16. The movable mold 20 has a hole 21 for setting the outer shape of the ferrule 5 and a tunoid pin 24. It consists of a micro pin 25 that is set in the cavity insertion piece 23 and can be inserted into the micro pin insertion hole 16 of the hole 15 described above.

In order to perform molding using a molding mold having this configuration, the identification mold 10 and the movable mold 20 are combined as shown in FIG. 5, and this is set in a molding machine.
may be injected into the -F molding resin injection port 11. By doing this, the resin 30 is gradually injected into the lower part of the cavity formed by the hole 21 of the movable mold body 22 and the core pin 15, and the resin 30 is injected into the lower part of the cavity formed by the hole 21 of the movable mold body 22 and the core pin 15. Since the resin 30 that has been removed has remained at the tip of the cylinder for a long time, it has progressed to deteriorate.
Physical property values such as molecular weight have decreased. Moreover, the air inside the cavity and the gas bubbles generated from the resin 30 have no place to escape, and the resin 30 cools while being fixed near the micro pin 25, resulting in the most important part of the ferrule 5 being the final product. This also causes the formation of micro holes i at the tip, variations in the external dimensions of this part, and even roughness of the external surface. In addition, a weld line formed by the convergence of the separated resin flows is formed at the tip of the T-rule 5, which reduces the mechanical strength.

[Object of the Invention] The present invention has been made based on the above circumstances, and it is possible to reduce variations in the microhole diameter of a molded product and the external dimensions of this part, and also to reduce the roughness of the external surface of the tip of the molded product. It is also an object of the present invention to provide a molding die that can prevent a decrease in the mechanical strength of the tip.

[Embodiments of the Invention] The present invention will be described below with reference to the drawings. Here, the description will be given by taking as an example a molding die used for molding a ferrule of an optical connector, but the molding die is not limited to this, and may be used for molding other products. FIG. 1 is a cross-sectional view showing one embodiment of the molding die of the present invention, which mainly consists of a fixed die 40, a movable die 50, a core pin sleeve 60.
] Consists of a core pin sleeve driving member 6. The fixed mold 40 has a plurality of injection ports 41 for molten material for molding, a guide hole 42, and a core pin insertion hole 43'+tJ, and a recess 46 that is located in the center and communicates with the upper surface of a movable mold body 53, which will be described later. , a fixed mold body 7!11 having a spring 63 whose one end is identified on the bottom surface of the recess 46 of the bracket, and a core pin 45.

This core pin 45 is rod-shaped, and has a flange 4 on yi.
5a, and a minute pin insertion hole 43b is formed at the other end. The core pin 45 is inserted and fixed into the core pin insertion hole 43 of the fixed mold body.

The movable mold 50 has a guide pin 51 at the upper end, a through hole 52 for setting the outer shape of the product at the center of the mold, and a position apart from the through hole 52 and the fixed mold. A movable mold body 53 having a dummy hole 56 that communicates with the recess 46 of the mold body 44, a cavity insertion piece (micro pin holder) 54 stepped and drilled at the bottom of the through hole 52 of this movable mold body 53, and this cavity. It consists of a minute pin 55 supported by an insertion piece 54.

An abin sleeve 6o is provided on the outer periphery of the core pin 45 so as to be movable up and down, and an abin sleeve driving member 62 is provided in the dummy hole 56 of the movable mold body 53 so as to be movable up and down. Core pin sleeve driving member 62
and the core pin sleeve 6o are connected by a connecting member 61 at their upper portions.

The fixed mold 4o, the movable mold 50, the abin sleeve 60, etc. configured in this way are combined as shown in FIG. The liquid is simultaneously injected little by little into each injection port 41.

Then, the molten material 70 for molding fills the through hole 52 and the core pin 45.
, the molding melt 70 is gradually injected into the product forming cavity formed by the core pin sleeve 60, and at the same time, the molding melt is also poured into the cavity formed by the dummy hole 56 and the core pin sleeve 1 driving member 62. The material 70 is gradually injected. In this case, the molten molding material 70 injected into the product forming cavity first reaches the bottom surface of the caviar eye, loses its escape, and empties into the first molding material formed by the core pin sleeve 60 and the tip of the core pin 45.
Enter the small space shown in the figure.

On the other hand, the liquid level of the molten material 70 for molding gradually rises, and along with this, the core pin sleeve driving member 6
2 moves in one direction against the pressing force of the spring 63. Along with this, the core pin sleeve 60 connected by the connecting member 61 gradually moves upward,
The final result will be as shown in Figure 2.

As the core pin sleeve 6o gradually moves upward in this way, the molten material 70 that has remained inside the cylinder for a long time, which becomes a problem in the ferrule that is the final product, is removed from the product forming cavity. Since the flow flows to a position N1 away from the bottom (the protrusion of the micro pin 55), the variation in the diameter of the micro holes in the ferrule is reduced, and the roughness of the outer surface of the tip of the ferrule is reduced. Further, since a welt line formed by the confluence of the molten material 7o injected from the injection port 41 is not formed at the tip of the ferrule, a decrease in mechanical strength can be prevented. Furthermore, core pin sleeve 60] Abin sleeve drive part IJ'62
Since the core pin sleeve 6 is moved upward by the molten molding material 70, the movement of the core pin sleeve 6 and the timing of its movement are ensured.

In the above-described embodiment, the molten material 7 for molding of the fixed mold 40
The injection port 41 of o is not formed in the movable mold body 53 but in the fixed mold body 44, since it is a flange part that does not require much dimensional accuracy of the ferrule, and after the ferrule is taken out from the mold. This is to facilitate processing.

Even if an extrusion pin is used in place of the spring 63 used in the above embodiment, the molded product can be easily taken out.

[Advantageous Effects of the Invention 1 Above] According to the present invention, it is possible to reduce variations in the microhole diameter of the molded product and the external dimensions of this part, and to reduce the roughness of the external surface of the tip of the molded product. It is possible to provide a molding die that can prevent a decrease in mechanical strength at the tip of a molded product.

[Brief explanation of the drawing]

Figures 1 and 2 both show an embodiment of a molding die according to the present invention, with Figure 1 being a cross-sectional view showing the initial state of molding, and Figure 2 showing the state in the middle of molding. cross section,
Figure 3 is a sectional view showing the schematic structure of the optical connector, Figures 4 and 5 are examples of conventional molding molds for manufacturing the ferrule shown in Figure 3, and Figure 4 is a cross-sectional view showing the schematic structure of the optical connector. FIG. 5 is a sectional view showing the state before molding, and FIG. 5 is a sectional view showing the state after molding. 40... Fixed mold, 41... Inlet, 42... Guide hole, 43... Core pin insertion hole, 44... Fixed mold body, 45... Core pin, 46... Hollow , 50・
...Movable mold, 51...Guide pin, 52...Through hole, 53...Movable mold body, 54...Cavity insertion piece, 55...Minute pin, 56...Dummy hole , 60
... ] Core pin sleeve 61 ... connection member, 62.
... Core pin sleeve drive = 81 member, 63... spring, 70... molten material for molding.

Claims (1)

[Claims] A fixed mold in which an injection port for molten material for molding is formed in the fixed mold body, and a core pin for setting the approximate inner shape of the product in the fixed mold body, and a fixed mold combined with this fixed mold. In this state, the core pin is inserted into the movable mold body, and a hole is formed to set the external shape of the product.
Furthermore, a core pin sleeve driving member is provided in the movable mold body to be vertically movable in the dummy hole in communication with the injection port, and a core pin sleeve driving member is provided on the outer periphery of the core pin to be vertically movable and connected to the core pin sleeve driving member. The core pin sleeve is configured to sequentially move the core pin sleeve driving member upward by the pressure of the melt molding material flowing from the injection port during molding, and accordingly move the core pin sleeve upward. A molding die characterized by: