JP2576743B2 - Compression mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for an injection compression molding machine.

[0002]

2. Description of the Related Art As a molding die, a compression hole is continuously provided in a cavity, and a compression pin is inserted into the compression hole to urge the cavity toward the cavity by a spring, and to a runner communicating with the cavity through a gate. A gate seal pin is provided to block the runner (gate) by being moved by the cylinder. The cavity is filled with resin and the gate is closed with the gate seal pin. The resin in the compression hole is compressed and compressed by the resin filling pressure. Further, there has been known a method in which the material is compressed into a cavity through a compression pin by the force of the spring and molded (Japanese Patent Laid-Open No. 58-131).
041).

In addition to the above, as a compression molding die, a compression hole is provided between a cavity and a gate, and a compression pin is moved by an ejector extruder to shut off the gate, and then the resin in the compression hole is removed. It is also known that a molding is performed by compressing the inside of a cavity with a compression pin (Japanese Patent Publication No. Hei 3-7705).
No. 1).

[0004]

In the former mold, the resin in the cavity cannot be compressed at a pressure higher than the filling pressure only by maintaining the pressure at the time of filling the resin until the resin is solidified. Therefore, there is a problem that sink, warp and shrinkage are apt to occur and a molded product with high dimensional accuracy cannot be obtained.

In the latter compression molding die, since the gate is blocked by the compression pin, it is necessary to provide the compression pin at the position of the gate, and there is a problem that the degree of freedom in design is narrow. The compression part in the compression molding is desirably a part where solidification progresses quickly (a part distant from the gate). However, in the above-described conventional compression molding mold, the resin is a gate part where solidification of the resin is slow. There is a complaint that the dimensional accuracy of the molded product does not improve as expected.

SUMMARY OF THE INVENTION An object of the present invention is to provide a compression molding die capable of obtaining a molded product having high dimensional accuracy without restriction on the equipment position of a compression pin.

[0007]

In order to achieve the above object, the present invention provides a mold body having a cavity and a runner communicating with the cavity, the mold body being attached to a mounting plate via a spacer block, A gate seal pin plate movably provided between the mounting plate and the mold body; a compression pin plate movably provided between the gate seal pin plate and the mold body; An ejector pin plate provided between the compression pin plate and the mold body, and an ejector pusher movably attached to the gate seal pin plate by being urged toward the mold body by an urging spring. A gate seal pin that blocks the runner at the initial stage of the pressing movement of the gate seal pin plate, and a compression hole formed in the mold body in communication with the cavity. The tip is inserted and attached to the compression pin plate, and after the gate seal pin shuts off the runner, the compression pin plate is moved toward the cavity by the pressing movement of the gate seal pin plate and the resin in the compression hole is moved. Into the cavity, and a compression pin that pushes out the molded product from the cavity when the mold is opened, and is attached to the ejector pin plate, and when the mold is opened, the runner moves by the pressing movement of the ejector pin plate by the compression pin plate. And an ejector pin for projecting the solidified resin therein.

[0008]

When the resin is completely filled in the cavity, the ejector pushing device is operated to push the gate seal pin plate toward the mold body. This movement of the gate seal pin plate moves the gate seal pin by being pushed by the biasing spring, and shuts off the runner. When the runner is shut off, the gate seal pin plate abuts against the compression pin plate and pushes it. Therefore, the compression pin moves to compress the resin in the compression hole into the cavity.

[0009] When the resin is compressed and solidified to an appropriate degree in this manner, the mold is opened as usual. At this time, the plate for the gate seal pin is moved by the operation of the ejector extruder as described above. , And the plate for the compression pin abuts on the plate for the ejector pin and pushes it, so that the molded product in the cavity and the solidified resin in the runner are pushed out of the cavity and the runner by the compression pin and the ejector pin.

Since the compression pin is configured to be compressed and moved by the ejector extruder, the resin can be compressed into the cavity with a strong force, and therefore, a molded product having no sink marks and warpage and high dimensional accuracy can be formed. be able to. Further, since the gate seal pin and the compression pin are provided separately, the compression pin can be provided, for example, at a position away from the gate to effectively compress the resin.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show an embodiment of a compression molding die according to the present invention. In the figure, reference numeral 1 denotes a mold body. The mold body 1 has a runner 1a, a cavity 1c connected to the runner 1a via a gate 1b, and a compression hole 1d. The compression hole 1d is open at a portion of the cavity 1c remote from the gate 1b. The mold body 1 is integrally mounted on a mounting plate 2 via a spacer block 3. The mounting plate 2 is mounted on a movable platen (not shown), and forms a movable mold together with the mold body 1 and the like. Reference numeral 4 denotes a fixed mold. The fixed mold 4 has a sprue 6 for receiving the injection of resin from the injection nozzle 5 and is attached to a fixed platen (not shown).

A plate 7 for a gate seal pin, a plate 8 for a compression pin, and a plate 9 for an ejector pin are provided between the mounting plate 2 and the mold body 1. And provided in the above order. The plate 7 for the gate seal pin is provided between the mounting plate 2 and the plate 8 for the compression pin, and the plate 8 for the compression pin.
Is between the step 3a formed on the spacer block 3 and the ejector pin plate 9, and the ejector pin plate 9 is freely between the other step 3b of the spacer block 3 and the mold body 1, respectively. You can move. Each plate 7, 8, 9 is composed of two plate-like members 7a, 7b, 8
a, 8b, 9a, 9b.

The movable shaft 11 is inserted into the mounting hole 7c formed in the plate 7 and is movably mounted in the axial direction in the gate seal pin plate 7, and is prevented from being pulled out by the head 11a formed at one end. Have been. Movable shaft 1
Reference numeral 1 denotes a gate seal pin 12 at an end on the mold body 1 side. The gate seal pin 12 is for blocking the runner 1a, is implanted in a mounting bracket 13 screwed to the movable shaft 11, and is movably inserted into a pin hole 1e formed in the mold body 1. ing. The movable shaft 11 penetrates through holes 8c, 9c individually formed in the compression pin plate 8 and the ejector pin plate 9, and is provided between the gate seal pin plate 7 and the mounting bracket 13 to form the above-described through hole. 8c,
It is urged toward the mold body 1 by an urging spring 14 inserted through 9c.

A compression pin 15 is fixed to the compression pin plate 8. The compression pin 15 compresses the resin in the compression hole 1d into the cavity 1c, and then pushes out the molded product W from the cavity 1c. The compression pin 15 penetrates through the through-hole 9d formed in the ejector pin plate 9 and has a tip portion. Is movably inserted into the compression hole 1d. A return spring 16 is provided between the compression pin plate 8 and the mold body 1 so as to pass through the through hole 9d.

Further, the ejector pin plate 9 is provided with ejector pins 17 and 18 and a return pin 19. The tips of the pins 17, 18, and 19 are individually movably inserted into pin holes 1f, 1g, and 1h formed in the mold body 1. Ejector pin 17,1
Reference numeral 8 extrudes a solidified resin Wa such as a runner 1a, and a return pin 19 fixes the ejector pin plate 9 at a predetermined position by abutting a tip of the return pin 19 to the fixed mold 4 at the time of mold clamping. Reference numeral 20 denotes an ejector pushing device such as a hydraulic cylinder that sequentially pushes the gate seal pin plate 7, the compression pin plate 8, and the ejector pin plate 9.

Next, the operation of the compression molding die according to the present invention configured as described above will be described. When the resin is filled in the cavity 1c as shown in FIG. 1, the ejector extruder 20 is operated to move the gate seal pin plate 7 to the position shown in FIG.
To move right. With this movement of the plate 7, the gate seal pin 12 is pushed to the right by the mounting bracket 13 by the urging spring 14, and shuts off the runner 1a (FIG. 3). At this time, since the mounting bracket 13 hits the mold body 1, no excessive force is applied to the gate seal pin 12.

When the runner 1a is shut off by the gate seal pin 12, the gate seal pin plate 7 contacts the compression pin plate 8 and pushes it to the right.
The compression pin 15 moves to the right to compress the resin in the compression hole 1d into the cavity 1c (FIG. 4). The compression of the resin is performed for a predetermined distance until the compression pin plate 8 contacts the ejector pin plate 9. At this time, the biasing spring 14 is compressed by the gate seal pin plate 7.

When the resin in the cavity 1c is compressed and appropriately solidified in this way, the mold is opened and the mold body 1 is separated from the fixed mold 4, and the ejector extruder 20 is operated to operate the gate seal pin. Continue pushing plate 7 to the right. For this reason, the compression pin plate 8 and the ejector pin plate 9 simultaneously move to the right to protrude the compression pin 15 and the ejector pins 17 and 18 to separate the molded product W of the cavity 1c and the solidified resin Wa of the runner 1a from them ( (Fig. 5). The return spring 16 is compressed by the compression pin plate 8.

After the molded product W and the solidified resin Wa are released from the mold,
5 until the ejector pushing device 20 operates in the reverse direction and the gate seal pin plate 7 hits the mounting plate 2.
To retreat to the left. With the retreat of the plate 5, the tip of the gate seal pin 12 retreats from the runner 1a to the pin hole 1e. Further, since the pressing of the compression pin plate 8 is released by the retreating movement of the gate seal pin plate 7, the plate 8 retreats to the mounting plate 2 side by the action of the return spring 16, and the tip of the compression pin 15 is compressed by the compression hole. Retreat within 1d, step 3
Stop at a.

With or after the above operation, the mold is clamped as usual. At this time, the return pin 19 comes into contact with the fixed mold 4 and moves rightward with respect to the mold body 1 to retreat the ejector pin plate 9. As a result, the ejector pin plate 9 separates from the mold body 1 and retreats the ejector pins 17 and 18 to stop in contact with the step 3b. In this state, the resin is injected from the injection nozzle 5, and the state is as shown in FIG. Hereinafter, the above operation is repeated to form the molded product W.

[0021]

As described above, the compression molding die of the present invention has a cavity and a runner communicating with the cavity, and is mounted on a mounting plate via a spacer block. A gate seal pin plate movably provided between the plate and the mold body; a compression pin plate movably provided between the gate seal pin plate and the mold body; An ejector pin plate provided between the pin plate and the mold body; and an ejector pushing device urged toward the mold body by an urging spring and movably attached to the gate seal pin plate. A gate seal pin that shuts off the runner in the initial stage of the pressing movement of the gate seal pin plate, and a distal end formed in a compression hole formed in the mold body in communication with the cavity. After being inserted and attached to the compression pin plate, after the gate seal pin shuts off the runner, the compression pin plate is pressed toward the cavity by the gate seal pin plate to move the resin in the compression hole into the cavity. And a compression pin that pushes out the molded product from the cavity when the mold is opened, and is attached to the ejector pin plate. Since the structure is provided with the ejector pins for projecting the solidified resin, the resin can be compressed into the cavity with a strong force. Therefore, it is possible to form a molded product having high dimensional accuracy without sink and warpage.

Also, since the gate seal pin and the compression pin are separately provided and share functions, the restriction on the installation position of the compression pin is small, the degree of freedom of design is wide, and the compression pin is separated from the gate, for example. In this position, the resin can be effectively compressed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a compression molding die according to an embodiment of the present invention, showing a state of being filled with a resin.

FIG. 2 is a front view showing a relationship between a cavity and a compression hole, and a relationship between a runner and a gate seal pin.

FIG. 3 is a sectional view showing a state in which a runner is blocked by a gate seal pin.

FIG. 4 is a sectional view showing a compressed state of a compression pin.

FIG. 5 is a cross-sectional view showing a protruding state of a compression pin and an ejector pin.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold main body 1a Runner 1b Gate 1c Cavity 1d Compression hole 2 Mounting plate 3 Spacer block 7 Gate seal pin plate 8 Compression pin plate 9 Ejector pin plate 12 Gate seal pin 14 Urging spring 15 Compression pin 17, 18 Ejector Pin 20 ejector extrusion device

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-193428 (JP, A) JP-A-1-118423 (JP, A) JP-A-58-133251 (JP, A) JP-A-58-1983 131041 (JP, A) JP 3-77051 (JP, B2)

Claims (1)

(57) [Claims] 1. A mold body having a cavity and a runner communicating with the cavity, the mold body being attached to a mounting plate via a spacer block, and a gate movably provided between the mounting plate and the mold body. A seal pin plate, a compression pin plate movably provided between the gate seal pin plate and the mold body, and an ejector pin provided between the compression pin plate and the mold body. And the gate spring pin is urged toward the mold body by an urging spring, and is movably attached to the gate seal pin plate to shut off the runner at an initial stage of the pressing movement of the gate seal pin plate by the ejector pushing device. A gate seal pin and a tip inserted into a compression hole formed in the mold body in communication with the cavity are attached to the compression pin plate, After the gate seal pin blocks the runner, the compression pin plate is moved toward the cavity by the pressing movement of the gate seal pin plate to compress the resin in the compression hole into the cavity, and when the mold is opened, the molded product is in the cavity. And an ejector pin attached to the ejector pin plate, the ejector pin being pushed to move the ejector pin plate by the compression pin plate when the mold is opened, and ejecting the solidified resin in the runner. Compression mold.