JPH1016006A - Injection molding and injection molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a material called 'resin' formed by the gelation of a residual gas in a vacuum suction path, in an injection molding method and an injection molding device for vacuum-sucking the interior of a cavity when a material resin in injected. SOLUTION: A cavity 2, vacuum suction lines 5, 7, 13, 14, 15, 16 connected to the cavity 2, and atmospheric exposure lines 6, 11, 15 connected to the vacuum suction lines 5, 7, 13, 14, 15, 16 near the cavity 2, are formed by mold clamping. In addition, an operation to vacuum-such the interior of the cavity 2 is initiated through the vacuum suction lines 5, 7, 13, 14, 15, 16 in such a state that the atmospheric exposure lines 6, 11, 15 are closed. Next, a material resin 17 is injected into the cavity 2, and further, it is started to cure the injected material resin. After that, the atmospheric exposure lines 6, 11, 15 are opened in the process of curing the material resin to suck an atmospheric air through the vacuum suction lines 5, 7, 13, 14, 15, 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel injection molding method and injection molding apparatus. More specifically, the present invention relates to an injection molding method and an injection molding apparatus for evacuating the inside of a cavity when injecting a material resin, and relates to a technique for preventing generation of a substance called gelled tar of gas remaining in an evacuating path.

[0002]

2. Description of the Related Art An example of a conventional injection molding apparatus is shown in FIG.

[0005] Reference numeral a denotes a mold, which comprises a fixed mold and a movable mold, and forms a cavity (not shown) by mold clamping.

[0004] Reference numeral b denotes a vacuum suction line, one end of which is connected to the cavity, the other end of which is connected to the vacuum pump c, and a solenoid valve d is interposed in the middle.

[0005] First, the solenoid valve d is opened, the vacuum pump c is driven to evacuate the cavity, and
While continuing the evacuation, the material resin is injected into the cavity.

[0006] Then, the material resin injected into the cavity is cured, and the molding is completed.

[0007]

However, according to the above-described conventional injection molding apparatus and injection molding method, there is a problem that a substance called a tar, which is formed by gelling excess gas, remains in the path of evacuation.

For example, when molding is performed using an FRP material containing unsaturated polyester as a main raw material, when evacuation is started, gases in the cavity and in the vacuum suction line b start to move, and when these degrees of vacuum are increased, When the material resin is injected, the material resin spreads in the cavity while emitting styrene gas. Then, when the filling of the material resin is completed, the material resin starts to cure and shuts off the gas inlet of the vacuum suction line b, so that the gas in the vacuum suction line b does not move thereafter. In this way, the gas containing the styrene gas remains in the vacuum suction line b, and the styrene gas is cooled and so-called tar (gelled styrene gas) adheres to the inner surface of the vacuum suction line b. Become.

When such a process is repeated, the vacuum suction line b is clogged with a resin and molding becomes impossible, or when the mold is opened after the molding, the resin is removed from the vacuum suction line b by a thread. There is a problem that a drawback such as being drawn out and adhering to a molded article occurs.

[0010] Therefore, an object of the present invention is to prevent the generation of a substance called gelled tar of gas remaining in the evacuation path.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an injection molding method comprising the steps of: clamping a mold; Forming an open-to-atmosphere line connected in the vicinity of, starting the evacuation of the cavity through the vacuum suction line with the open-to-atmosphere line closed, then injecting material resin into the cavity, Further, the curing of the injected material resin is started, the atmosphere opening line is opened during the curing of the material resin, and the atmosphere is sucked through a vacuum suction line. A mold for forming a cavity by clamping, a vacuum suction line connected to the cavity, and vacuum generation for evacuating the cavity through the vacuum suction line. A first valve interposed in the vacuum suction line, an open air line having one end connected to the vacuum suction line near the cavity, and the other end open to the atmosphere, The second inserted in the line
After the mold is closed, the first valve is opened and the second valve is closed, and the vacuum generator is started to start the evacuation of the cavity. Then, during curing of the material resin, the second valve is opened to connect the vacuum suction line to the atmosphere through the atmosphere release line, and the atmosphere is sucked through the atmosphere release line and the vacuum suction line. It is something to do.

Therefore, according to the injection molding method and the injection molding apparatus of the present invention, the flow of gas in the vacuum suction line is maintained even after the start of curing of the injected material resin. The gas to be discharged can be discharged from the vacuum suction line, and therefore, it is possible to prevent the gelled resin from remaining in the vacuum suction line due to the gas.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the injection molding method and the injection molding apparatus of the present invention will be described below with reference to the attached drawings.

First, the outline of the injection molding apparatus will be described.

Reference numeral 1 denotes a mold, which includes a fixed mold 1a and a movable mold 1b. A projection 2a for forming a cavity is formed in the fixed mold 1a, a concave portion 2b for forming a cavity is formed in the movable mold 1b, and the fixed mold 1a and the movable mold 1b are joined to each other. The cavity 2 in which the material resin is filled is formed by clamping the mold in a state in which the butt is abutted.

A material resin injection hole 3 is formed in the vicinity of the cavity forming projection 2a of the fixed mold 1a, and a portion of the movable mold 1b opposed to the material resin injection hole 3 is used for forming the cavity. A gate recess 4 'is formed at a position connecting the recess 2b, and a gate 4 is formed by clamping the fixed mold 1a and the movable mold 1b. The injection hole 3 and the cavity 2 are communicated.

The fixed side mold 1a has a vacuum hole 5 having one end opened at a position close to the cavity forming projection 2a.
Is formed, and an air leak hole 6 having one end opened at a position close to the vacuum hole 5 is formed.

Reference numeral 7 denotes a vacuum hose, which connects the other end of the vacuum hole 5 to the vacuum pump 8.

A first solenoid valve 9 is inserted in the middle of the vacuum hose 7, and a monomer is provided between the first solenoid valve 9 of the vacuum hose 7 and the other end of the vacuum hole 5. Tank 1
0 is inserted.

An air leak hose 11 connects the other end of the air leak hole 6 to the atmosphere by the air leak hose 11, and a second solenoid valve 12 in the middle of the air leak hose 11. Is inserted.

Cavity forming recess 2 of movable mold 1b
A concave portion 13 'for an air pool is formed at a position close to "b", and a concave groove 14' for a connection path is formed so as to connect the concave portion 13 'for the air pool and the concave portion 2b for forming a cavity. Further, a concave portion 15 ′ for a vacuum groove is formed so as to connect a position of the movable mold 1 b facing the vacuum hole 5 of the fixed mold 1 a and a position facing the atmosphere leak hole 6. A connection groove 16 ′ is formed to connect the recess 15 ′ and the air pool recess 13 ′.

Thus, the fixed mold 1a and the movable mold 1
b and the air pool 13 and the vacuum groove 1
5 and connection paths 14 and 16 are formed.
3 and the cavity 2 are connected by a connection path 14, the air pool 13 and the vacuum groove 15 are connected by a connection path 16, and the vacuum hole 5 and the atmospheric leak hole 6 are connected by a vacuum groove 15. Is communicated by

The connection path 14, the air pool 13,
A vacuum suction line is formed by the connection path 16, a part of the vacuum groove 15, the vacuum hole 5, and the vacuum hose 7.
5, an atmosphere leak hole 6 and an atmosphere leak hose 11 form an atmosphere release line.

Next, for example, using the above-described injection molding apparatus,
The molding using an FRP material containing unsaturated polyester as a main raw material will be described with reference to the time chart of FIG. 6 and FIGS. 3 to 5.

The mold 1 is clamped. At this time, the first and second solenoid valves 9 and 12 are both closed.

Next, the first solenoid valve 9 is opened and the vacuum pump 8 is operated to evacuate the cavity 2 (see FIG. 3). Thereby, the space in the mold 1, that is, the cavity 2, the air pool 13, the vacuum groove 15, the vacuum hole 5
Gas starts to be sucked by the vacuum pump 8 (the flow of gas is indicated by an arrow).

The material resin 17 (shown in a satin pattern) is injected through the material resin injection hole 3 with a delay of a predetermined time, for example, 1 second, from the start of the evacuation described above (see FIG. 4). Thereby, the material resin 17 spreads into the cavity 2 while generating styrene gas.

When the injection of the material resin 17 is completed, the curing of the material resin 17 is started by the heated mold 1. During this time, the second solenoid valve 12 is opened to allow the vacuum groove 15 to communicate with the atmosphere (see FIG. 5). As a result, the atmosphere flows into the vacuum suction line via the atmosphere release line and is sucked by the vacuum pump 8, so that the flow of gas (indicated by an arrow) in the vacuum suction line continues, The styrene gas does not stay in the vacuum suction line.

The monomer tank 10 absorbs the organic substance flowing through the vacuum hose 7 and prevents the vacuum pump 8 from being damaged by the organic substance.

Then, the first and second solenoid valves 9 and 12 are closed, and after the injected material resin 17 is completely cured,
The mold 1 is opened and the molded product is taken out.

According to the injection molding method and the injection molding apparatus of the present invention, even after the material resin 17 starts to harden, the gas flow continues in the vacuum suction line. Does not remain, and the vacuum suction line does not become clogged with the die, and when the mold is opened after molding, the die is pulled out from the vacuum suction line into a thread and adheres to the molded product. No problems occur.

[0032]

As is apparent from the above description, the injection molding method of the present invention is characterized in that the mold is clamped and the cavity, a vacuum suction line continuous with the cavity and connected to the vacuum suction line near the cavity. A vacuum opening line is formed, and the inside of the cavity is started to be evacuated via the vacuum suction line in a state where the atmosphere opening line is closed, and then the material resin is injected into the cavity and further injected. The curing of the material resin is started, the atmosphere opening line is opened during the curing of the material resin, and the atmosphere is sucked through a vacuum suction line.

Further, the injection molding apparatus of the present invention comprises a mold for forming a cavity by clamping, a vacuum suction line connected to the cavity, and a vacuum generator for evacuating the cavity through the vacuum suction line. A first valve interposed in the vacuum suction line, an air release line having one end connected to the vacuum suction line near the cavity and the other end open to the atmosphere, And a second valve inserted therein, and after clamping the mold,
With the first valve opened and the second valve closed, the vacuum generator is started to start the evacuation of the cavity, and the material resin is injected into the cavity. The second valve is opened to connect the vacuum suction line to the atmosphere through an atmosphere release line, and the atmosphere is sucked through the atmosphere release line and the vacuum suction line.

Therefore, according to the injection molding method and the injection molding apparatus of the present invention, the gas flow in the vacuum suction line is maintained even after the curing of the injected material resin is started. The gas to be discharged can be discharged from the vacuum suction line, and therefore, it is possible to prevent the gelled resin from remaining in the vacuum suction line due to the gas.

It should be noted that the specific shapes or structures of the respective parts shown in the above-described embodiment are merely examples of the embodiment of the present invention, and the technical features of the present invention are not limited thereto. The scope should not be construed as limiting.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an embodiment of an injection molding apparatus according to the present invention, in which a fixed mold and a movable mold are arranged side by side;
Further, the abutting surface is shown on the paper surface side.

FIG. 2 is an enlarged cross-sectional view showing a state in which a mold is closed by cutting at a position indicated by line II-II in FIG.

FIG. 3 is a schematic diagram showing a molding process in order together with FIGS. 4 and 5, and this drawing shows a state in which evacuation is started.

FIG. 4 shows a state in which injection of material resin has started.

FIG. 5 shows a state in which the injection of the material resin is completed.

FIG. 6 is a time chart of a molding step.

FIG. 7 is a view schematically showing a conventional injection molding apparatus.

[Explanation of symbols]

1: mold, 2: cavity, (5, 7, 13, 14, 1
5, 16) ... vacuum suction line, 5 ... vacuum hole, (6, 1)
1, 15) ... atmosphere open line, 6 ... atmosphere leak hole, 7 ...
Vacuum hose, 8: vacuum pump (vacuum generator), 9: first solenoid valve (first valve), 11: atmospheric leak hose, 1
2 ... second solenoid valve (second valve), 13 air pool, 1
4: Connection path, 15: Vacuum groove, 16: Connection path, 17: Material resin

Claims (2)

[Claims] 1. A mold is clamped to form a cavity, a vacuum suction line connected to the cavity, and an open-to-atmosphere line connected to the vacuum suction line in the vicinity of the cavity, wherein the open-to-atmosphere line is closed. Initiate evacuation of the cavity through the vacuum suction line, inject the material resin into the cavity, and start curing the injected material resin. An injection molding method characterized by opening an open line and sucking air through a vacuum suction line. 2. A mold for forming a cavity by clamping, a vacuum suction line connected to the cavity, a vacuum generator for evacuating the cavity through the vacuum suction line, and A first valve connected to the vacuum suction line at one end in the vicinity of the cavity, and an open air line having the other end opened to the atmosphere; After the mold has been clamped, the first valve is opened and the second valve is closed to activate the vacuum generator to start the evacuation of the cavity. After injecting the resin, the second valve is opened during the curing of the material resin, and the vacuum suction line communicates with the atmosphere via an atmosphere release line,
An injection molding apparatus wherein the atmosphere is sucked through an atmosphere opening line and a vacuum suction line.