JP2724907B2 - Vacuum forming mold equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vacuum molding die apparatus for evacuating a cavity of a die in resin molding such as injection molding or injection compression molding.

(Prior art) Conventionally, in resin molding such as injection molding or injection compression molding, the residual air is insulated when molten resin is injected into the cavity unless the cavity of the mold is kept in a vacuum state. It was compressed and had an adverse effect on the resin molded product. For this reason, a gap called an air vent is provided in a part of the mold, and air escapes from the gap.

For the escape of this air, for example, one connected to a vacuum tank disclosed in Japanese Utility Model Laid-Open No. 34416/1985,
Japanese Patent Application Laid-Open No. 59-222321 discloses a device using a vacuum pump.

(Problems to be Solved by the Invention) However, in any of the above cases, since the exhaust device is provided outside the mold, since the cavity is connected to the device via the exhaust pipe from the cavity of the mold, the piping resistance is large. There is a drawback that the suction efficiency deteriorates.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vacuum molding die apparatus capable of increasing the exhaust efficiency and evacuating the die in a short time. Things.

(Means for Solving the Problems) In order to achieve the above object, a vacuum molding die apparatus of the present invention comprises: (1) In a die for injection molding or injection compression molding,
A vacuum tank is provided in the mold, the vacuum tank and the cavity of the mold are communicated via a valve, the valve is opened in connection with the mold closing operation, and the gas in the cavity is introduced into the vacuum tank. In a mold for injection molding or injection compression molding, a cylinder portion is attached to a fixed side mold plate of the mold, and a piston portion is provided in a chamber in the cylinder portion. The piston part is provided with a rod part, which is connected to the movable mold plate and can be interlocked, pushes up the piston part when the mold is closed, the chamber is evacuated, and the cylinder part is fixed to the chamber. It is connected to the cavity of the template via an exhaust path, and in this exhaust path, an open / close pin for closing the exhaust path by the elastic force of a spring is provided, and the movable side mold plate has an open / close pin when the mold is closed. Pushing and discharging An opening / closing operation pin for opening an air passage is provided.

(Operation) The vacuum molding die apparatus of the present invention configured as described above is provided with a vacuum tank provided in the die or a pump comprising a cylinder part and a piston part provided in the die, and a pump in the die cavity. An exhaust path for sucking gas is connected, and a valve or an opening / closing pin that opens the exhaust path in connection with the mold closing operation of the mold is provided in the exhaust path, so that the exhaust path is short, and the exhaust efficiency is increased and the exhaust path is shortened. The inside of the mold can be evacuated.

(Embodiment 1) Hereinafter, the embodiment of the present invention is divided into first and second embodiments, the first embodiment is shown in FIGS. 1 and 2, and the second embodiment is shown in FIGS. This will be described with reference to FIG.

FIG. 1 is a cross-sectional view of the vacuum molding die apparatus of the present invention. In the figure, reference numeral 1 denotes a fixed-side mounting plate, and a fixed-side mold plate 2 is provided below the fixed-side mounting plate 1. A cavity 3 is provided at a substantially central portion inside the fixed mold plate 2, and a groove is provided around the cavity 3.
A sealing material 4 for sealing, preferably a hollow O-ring, is fitted in the groove. A movable mold plate 5 is abutted on the lower side of the fixed mold plate 2 provided with the cavity 3. On a surface of the movable mold plate 5 in contact with the fixed mold plate 2,
At a position corresponding to the cavity 3, a cavity 3 'corresponding to the cavity 3 is provided. A plurality of exhaust passages 6 are provided in the vicinity of the cavity 3 'and inside the mounting portion of the sealing material 4 so as to extend vertically through the movable mold plate 5.

A spacer block 7 is provided below the movable mold plate 5. In the interior of the spacer block 7, there is formed a pushing space 8 which collectively includes a plurality of exhaust passages 6 provided in the movable mold plate 5, and around this pushing space 8, An isolated vacuum tank 9 is provided in the spacer block 7. A second exhaust path 10 is provided between the vacuum tank 9 and the pushing space 8, and the second exhaust path 10
A valve 11 is mounted on the pushing space 8 side of the exhaust path 10 of the
The open port side of 11 protrudes into the pushing space 8. A suction hole 12 communicating with the vacuum tank 9 is provided on the outer peripheral wall side of the spacer block 7, and a pipe 13 connected to a pump (not shown) provided outside is attached to the suction hole 12. . The movable-side mounting plate 14 is in close contact with the lower side of the spacer block 7 configured as described above.

The vacuum molding die apparatus A having the above configuration is set in the molding machine, the pipe 13 is connected to a vacuum pump or the like provided outside, the valve 11 is closed, and the vacuum pump is operated, so that the vacuum pump 9 is placed in the vacuum tank 9. Is always kept in a vacuum state.
In this state, when the molding machine applies pressure from the movable mold plate 14 to perform the mold closing operation, the sealing material 4 provided on the fixed mold plate 2 comes into contact with the movable mold plate 5 and the cavities 3, 3 '.
Will be kept sealed. At the time of this seal the valve
By opening 11, the gas in the cavities 3 and 3 ′ is sucked by the negative pressure of the vacuum tank 9 through the pushing space 8 and the exhaust path 6 communicating with the pushing space 8 and the inside of the cavities 3 and 3 ′ is evacuated. And In this case, the time required for the exhaust is the pushing space 8.
And the exhaust passage 6 has a very small number of conduits, so that a vacuum state is established in a short time. When the resin material is injected from the nozzle of the molding machine after the mold is completely closed in this way, the injected resin material fills the cavities 3, 3 '.

After resin molding, the valve 11 is closed as shown in FIG. 2, and when the pressing of the molding machine is released, the movable-side fixed plate 14, the spacer block 7 and the movable-side mold plate 5 are integrally formed by the fixed-side mold plate 2. As a result, the cavities 3 and 3 'are separated into two parts so that the molded product can be taken out. At this time, the sealing material 4 is elastically restored and swells from the groove. Hereinafter, the pressurizing mold is closed by the molding machine, the valve is opened, the resin material is automatically injected, and the like, so that the resin molding can be performed continuously. During this time, the inside of the vacuum tank 9 is always kept in a vacuum state.

(Embodiment 2) FIGS. 3 and 4 are sectional views of a vacuum molding die apparatus B according to a second embodiment of the present invention.

In FIG. 3, reference numeral 15 denotes a fixed-side mounting plate, on which a fixed-side mold plate 16 is mounted. A sprue 18 for injecting a resin material is arranged at the center of the fixed mold plate 16, and communicates with the female recess 16a by a runner 33 and a gate. Also, the recess 16a
An air vent path 17 is provided in a direction opposite to the gate, and communicates with an exhaust path 19. The other end of the exhaust path 19 is connected to a cylinder section 20 attached to the fixed side template 16. An opening / closing pin 22 provided via a spring 21 is mounted in the middle of the exhaust path 19, and the opening / closing pin 22 is protruded into the exhaust path 19 by the elastic force of the spring 21 so as to close the exhaust path 16. It is composed. The insertion hole 23 through which the opening / closing pin 22 is inserted penetrates to the lower surface of the fixed side mold plate 16.

On the other hand, the upper surface of the movable mold plate 24 is provided with the female mold 16a.
And a male mold 24a corresponding to the
There is an open / close operating pin 25 for pushing up 2,
When the opening / closing operation pin 25 pushes up the opening / closing pin 22 in the insertion hole 23, the exhaust path 19 is electrically connected. A groove is surrounded around the upper surface of the movable mold plate 24, and a seal member 26 is fitted therein. At a position corresponding to the cylinder portion 20 on the side surface of the movable side mold plate 24, a rod portion 28 having a piston portion 27 at the tip is attached, and the piston portion 27 is housed in the cylinder portion 20, The portion 27 is provided so as to be located above the exhaust path connection port of the cylinder portion 20. With this arrangement, the inside of the cylinder section 20 is divided into an A chamber 29 and a B chamber 30.
An exhaust port 31 opened to the outside air is provided on the top surface of the A chamber 29 of the cylinder section 20. Although not shown, a movable-side mounting plate is provided below the movable-side mold plate 24, and is configured to be mounted on a movable pressing portion of the molding machine.

When the movable mold plate 24 is pushed up and the mold is closed as shown in FIG. 4 by a known means, the rod unit 28 pushes up the piston unit 27. The air in the chamber A 29 of the cylinder section 20 is extruded into the atmosphere from the exhaust port 31, and the inside of the chamber B has a negative pressure substantially close to vacuum. At this time, the open / close pin 22 is pushed up by the open / close operation pin 25, and the exhaust path 19 is opened, and the gas in the cavity 32 formed by the female mold 16a and the male mold 24a is exhausted through the air vent path 17. It is sucked into the B chamber of the cylinder part 20 through the passage 19,
The inside of the cavity 32 is substantially in a vacuum state, and the resin material injected from the spool 18 is quickly filled in the cavity 32.

When resin molding is performed in this manner, the pressing of the molding machine is released, the movable mold plate 24 is moved downward in the drawing, the open / close operating pin 25 is lowered, and the open / close pin 22 is urged by the spring 21. The exhaust path 19 is closed. Also, the rod part 28 is the piston part 27
Is drawn downward, the atmosphere is sucked into the A chamber 29, and the operation returns to the state shown in FIG.

In this example, the cylinder 20 is provided on the fixed mold 16, but the cylinder 20 is provided on the movable mold 24, and the piston 27 and the rod 28 are provided on the fixed mold 16. Can perform the same function. Also the cavity
The timing of bringing the inside of the vacuum 32 into a vacuum state can be arbitrarily set by changing the length of the opening / closing operation pin 25. To change the magnitude of the negative pressure, the diameter of the cylinder 20 or the cylinder It is possible by increasing or decreasing the number of 20.

FIGS. 5A and 5B show examples of the shape of the opening / closing operation pin 25 in this embodiment. The gas in the cavity 32 is sucked into the cylinder section 20 through both sides of the small-diameter section 51 of the tip of the opening / closing operation pin 25 or through the slit section 52.

(Effects of the Invention) As described above, according to the present invention, (1) In a mold for injection molding or injection compression molding,
A vacuum tank is provided in the mold, the vacuum tank and the cavity of the mold are communicated via a valve, the valve is opened in connection with the mold closing operation of the mold, and the gas in the cavity is evacuated by the vacuum. (2) In a mold for injection molding or injection compression molding,
A cylinder portion is attached to the fixed mold plate of the mold, and a piston portion is provided in a chamber in the cylinder portion, and a rod portion is provided in the piston portion, and the rod portion is connected to the movable mold plate. When the mold is closed, the piston section is pushed up, the chamber is evacuated, and the chamber in the cylinder section and the cavity of the fixed mold plate are connected via an exhaust path. An open / close pin that closes the exhaust path by elastic force is provided, and an open / close operating pin that pushes up the open / close pin when the mold is closed and opens the exhaust path is provided on the movable mold plate. This eliminates the need for ancillary equipment, makes it possible to increase the evacuation efficiency and evacuate the inside of the mold in a short period of time, and has the advantage that molded articles with less burrs and the like can be formed automatically and continuously.

[Brief description of the drawings]

1 and 2 show a first embodiment of the present invention. FIG. 1 is a cross-sectional view of a vacuum-forming mold device in a mold-closed state, FIG. 3 and 4 show a second embodiment of the present invention. FIG. 3 is a cross-sectional view of a vacuum forming mold device in a mold open state, and FIG. 4 is a cross-sectional view of the same device in a mold closed state. FIGS. 5A and 5B show examples of the shape of the opening / closing operation pin 25 in the second embodiment. A, B: Vacuum forming mold device 2, 16: Fixed side mold plate 3, 3 ', 32 ... Cavity 5, 24 ... Movable side mold plate 6, 19 ... Exhaust passage 9 ... Vacuum tank 11… Valve 20… Cylinder 22… Open / close pin 25… Open / close operating pin 27… Piston

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiko Machida 1048 Oaza Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP-A-2-155712 (JP, A)

Claims (2)

(57) [Claims] In a mold for injection molding or injection compression molding, a vacuum tank is provided in the mold, and the vacuum tank and a cavity of the mold are communicated via a valve to close the mold. Wherein the valve is opened, and the gas in the cavity is sucked into the vacuum tank. 2. A mold for injection molding or injection compression molding, wherein a cylinder portion is attached to a fixed side mold plate of the mold.
And a piston part is provided in the chamber in this cylinder part, a rod part is provided in this piston part, this rod part is connected to the movable mold plate, it can be interlocked, and pushes up the piston part when the mold is closed, The chamber is evacuated, and the chamber in the cylinder portion and the cavity of the fixed-side mold plate are connected via an exhaust path. The exhaust path is provided with an opening / closing pin for closing the exhaust path by the elastic force of a spring. Along with
A mold device for vacuum forming, wherein a movable side mold plate is provided with an opening / closing operation pin for pushing up an opening / closing pin when a mold is closed to open an exhaust passage.