JPH05131510A - Resin molding method and molding die - Google Patents

Abstract

PURPOSE:To provide the stamping molding method and a molding die used in said method. CONSTITUTION:A mold M consists of a fixed mold 1, an intermediate plate 3 and a movable mold 2, and a cam 22 movable back and forth by a hydraulic cylinder 2 and a retaining pin 21 projected in the direction of the intermediate plate 3 by the back and forth movement of said cam 22 are installed on the movable mold 2. An interval L in formed between the intermediate plate 3 and the movable mold 2, and a cavity 14 is formed in said mold M by first protruding the retaining pin 21 and then mold clamping, and resin is injected. After that, the retaining pin 21 is moved backward and the intermediate plate 3 and the movable mold 2 are mold clamped completely and a resin product is molded by stamping molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding method and a molding die, and more particularly, to a stamping molding method in which the mold is closed halfway and then resin is injected to perform mold clamping, and a method therefor. The present invention relates to a molding die used.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, stamping molding, in which a mold is temporarily stopped and a resin is injected, and then the mold is completely closed, is a molding die M in which a large number of pieces are taken in one molding.
Uses a hot runner structure and uses a fixed mold 3, a movable mold 2, and a slide core 5. That is, fixed type 3
A hot runner block 16 and a hot runner nozzle 17 provided inside adjust the temperature of the runner and the nozzle to inject resin into the cavity 14 formed by the fixed mold 3, the movable mold 2 and the slide core 5, and then stamping molding. Was going on.

[0003]

However, when the molding die M is used, the injection amount of the resin varies due to the variation in the temperature of the hot runner nozzle 17, which is a cause of defective molding. Moreover, since the hot runner block 16 and the hot runner nozzle 17 are provided in the molding die, the cost of the molding die is high, and the hot runner block 16 and the hot runner of the molding die are expensive. Since the temperature of the nozzle 17 is adjusted, the running cost is high. Then, auxiliary equipment such as a temperature controller was required.

[0004]

In order to solve the above problems, the present invention provides a movable die, a fixed die, an intermediate plate, and a holding member for holding the mold closed state of the fixed die and the intermediate plate. A resin molding method using a metal mold, wherein the fixed mold forming the resin passage and the mold closure of the middle plate are held by the holding member, and the middle plate and the movable mold are opened at a predetermined interval. The mold is closed, the resin is injected between the movable mold and the middle plate through the resin passage, and the mold is closed again between the movable mold and the middle plate to form a cavity and resin molding. A resin molding method is used which is characterized by molding the product.

The molding die used in the above invention is a molding die composed of a fixed die, an intermediate plate, a movable die and a holding member, wherein the holding member is arranged on the movable die side, It is characterized in that it comprises a holding pin capable of advancing and retracting from the movable die toward the middle plate, and a moving means for fixing the advanced state of the holding pin.

[0006]

In the resin molding method described above, since the mold closing between the fixed mold and the intermediate plate is held by the holding member, the resin is provided between the intermediate plate and the movable mold through the resin passage formed by the fixed mold and the intermediate plate. Even in the injected state, the mold closing of the fixed mold and the middle plate is maintained. After that, the fixing of the holding member in the protruding state is released, and the holding member is retracted so that the mold is closed again between the movable mold and the intermediate plate, and the mold is completely clamped to obtain the desired resin molded product. ing.

[0007]

EXAMPLES Next, examples of the resin molding method and the molding die according to the present invention will be described with reference to FIGS.

The molding die M shown in FIG. 1 has a fixed die 1, a movable die 2, an intermediate plate 3, and a slide core 5 as main components, and the fixed die 1 includes a mounting plate 11 and a runner plate 12. The movable die 2 is provided with a holding member including a holding pin 21, a cam 22 and a hydraulic cylinder 23, and an auxiliary spring 24.

A resin passage 111 supplied from a nozzle (not shown) of the injection molding machine is formed in the mounting plate 11, and this resin passage 111 leads to a resin passage 112 formed by the runner plate 12 and the intermediate plate 3. I understand.

The intermediate plate 3 has a movable rod 31 which determines the mold opening amount, and is attached so as to be slidable by a guide pin attached to the attachment plate 11. Also,
In the lower part of the intermediate plate 3, a recess is provided in which the slide core 5 which slides by the slide pin 51 is arranged. Then, the resin passage 11 formed by the middle plate 3 and the runner plate 12
2 communicates with a gate 13 which communicates with a cavity 14 formed by the intermediate plate 3, the movable die 2 and the slide core 5.

The slide core 5 is slidably provided by the movement of a bent slide pin 51 fixed to the intermediate plate 3.

On the other hand, the movable die 2 is provided with a holding pin 21 protruding toward the middle plate 3 by moving a cam 22 having a lower position 221 and a higher position 222 on the upper surface by a hydraulic cylinder 23. An auxiliary spring 24 is provided in order to prevent the middle plate 3 and the runner plate 4 from opening when the fixing is released and the mold is closed again.

Explaining the molding method, first, the mold M is
The mold is open between the movable mold 2 and the middle plate 3, between the middle plate 3 and the runner plate 12, and between the mounting plate 11 and the runner plate 12. In this state, the skin I is set on the surface of the movable die 2 forming the cavity 14. After that, by moving the hydraulic cylinder 23 forward, the lower surface 211 of the holding pin 21 is moved from the lower position 221 on the upper surface of the cam 22 to the higher position 222, and the holding pin 21 is projected from the surface of the movable die 2 toward the intermediate plate 3. Then the mold is closed.

Then, as shown in FIG. 2, the holding pin 21
Is protruded in the direction of the middle plate 3 by a distance of L, so that a gap corresponding to the protrusion L of the holding pin 21 is opened between the movable die 2 and the middle plate 3. At this time, the slide core 5 is already moved to the position when the mold is closed by the bent slide pin 51,
The movable mold 2, the slide core 5, and the intermediate plate 3 form a cavity 14
Is formed.

In this state, the resin is injected from the injection molding machine through the resin passages 111 and 112 and the gate 13 into the cavity 14
It shoots in. At this time, since the distance L is held by the holding pin 21, the runner plate 12 and the intermediate plate 3, and the runner plate 12 and the mounting plate 11 do not open when the resin is injected.

Then, after that, the hydraulic cylinder 9 retracts and the cam 22 retracts accordingly, so that the lower surface 211 of the holding pin 21 moves from the high position 222 to the low position 221.
Moves. At this time, the auxiliary spring 24 prevents the space between the middle plate 3 and the runner plate 12 and the space between the runner plate 12 and the mounting plate 11 from opening due to the residual pressure of the resin in the resin passage 112.
Prevents the mold from opening.

After making the holding pin 21 retractable, the mold M is clamped again to eliminate the gap L between the movable mold 2 and the fixed mold 3 and stamping molding is carried out to obtain a resin molding with a predetermined skin. Mold.

When the mold opening operation is started after the molding, the runner plate 12 and the intermediate plate 3 are opened first, and the molded product and the resin of the gate 13 are separated. At this time, the gate 13 and the resin gate in which the resin passage 112 is solidified follow the runner plate 12 side. Then, the space between the runner plate 12 and the mounting plate 11 is opened, the resin gate attached to the runner plate 12 is released, and finally the middle plate 3
And the movable die 2 open, and the slide pin 6 follows this movement.
The slide core 5 moves along with it, and the resin-molded product with the skin can be taken out from the mold M.

[0019]

EFFECTS OF THE INVENTION Since the holding member holds the middle plate and the fixed mold, the hot runner structure is not required. Therefore, the die cost can be reduced, and the die maintenance cost can be reduced. Further, since it is not necessary to adjust the temperature of the hot runner nozzle, defects in the molded product due to variations in the injection amount of resin are reduced. In addition, low pressure molding can be performed using an ordinary injection molding machine.

[Brief description of drawings]

FIG. 1 is a view showing a mold of the present invention, showing a state in which the mold is completely closed.

FIG. 2 is a view showing a mold of the present invention, in which the mold is closed halfway and a resin is injected.

FIG. 3 is a diagram in which the mold of the present invention is closed to the state of FIG. 2 and resin is injected into the cavity.

FIG. 4 is a view of a mold having a conventional hot runner structure.

[Explanation of symbols]

 1 Fixed type 11 Mounting plate 12 Runner plate 2 Movable type 21 Holding pin 3 Middle plate 5 Slide core M Mold L spacing

Claims (2)

[Claims] 1. A resin molding method using a mold provided with a movable die, a fixed die, an intermediate plate, and a holding member for holding the closed state of the fixed die and the intermediate plate, wherein a resin passage is formed. Hold the mold closing of the fixed mold and the middle plate by the holding member, perform mold closing so as to open the predetermined distance between the middle plate and the movable mold, and between the movable mold and the middle plate. A resin molding method comprising injecting a resin through the resin passage, closing a mold between the movable mold and the middle plate again to form a cavity and molding a resin molded product. 2. A molding die comprising a fixed die, an intermediate plate, a movable die and a holding member, wherein the holding member is arranged on the movable die side and is movable back and forth from the movable die toward the intermediate plate. A molding die comprising a holding pin and a fixing means for fixing the advancing state of the holding pin.