JPH11254117A - Device for adjusting degree of vacuum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for adjusting the degree of vacuum which can restrain defective casting surface, etc., caused by early sucking of molten metal, by arranging a variable throttle valve in a pipe line between a vacuum tank and a vacuum valve and adjusting the degree of vacuum in a die for die casting machine, etc., without correcting the position of an injection plunger. SOLUTION: In the die M, a cavity 1 communicated with an injection sleeve is formed and a chill vent 2 for exhausting gas in the cavity 1 is arranged. In the pipe line between the vacuum tank 3 connected with a vacuum pump P and the chill vent 2, an on-off valve 8, a variable throttle valve 4, a filter 6 and a stop valve 7 are arranged, and this device is constituted so as to adjust the degree of vacuum in the cavity 1 of the die M for the die casting machine and exhaust the gas in the die.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for adjusting the degree of vacuum in a mold such as a die casting machine.

[0002]

2. Description of the Related Art A conventional vacuum degree adjusting device is disclosed in Japanese Unexamined Patent Publication No.
No. 9063 and JP-A-7-171665,
The vacuum device generally includes a vacuum tank and a vacuum valve. In order to further enhance the accuracy of the degree of vacuum in the mold cavity, as disclosed in Japanese Patent Application Laid-Open No. 8-33258, the opening and closing time and opening and closing timing of the vacuum valve are adjusted in conjunction with the position of the injection plunger. I made it.

[0003]

However, in the conventional vacuum adjusting device, a method of controlling the degree of vacuum by starting gas release from the cavity in conjunction with the position of the injection plunger in the injection molding process is a control device. In addition to the cost increase, it takes time to determine the position of the injection plunger, and improvement has been required.

[0004] It is an object of the present invention to provide a vacuum degree adjusting device capable of suppressing a casting surface defect or the like due to "lead-in" of molten metal without correcting the position of an injection plunger.

[0005]

SUMMARY OF THE INVENTION A vacuum degree adjusting apparatus of the present invention is an apparatus for adjusting the degree of vacuum of a mold cavity such as a die casting machine. A variable throttle valve is provided in the pipeline between the vacuum tank and the vacuum valve connected to the vacuum pump at the start position and the stroke end position to adjust the degree of vacuum in a mold such as a die casting machine. . The variable throttle valve is a variable throttle valve that sets the throttle amount manually or by a servomotor.

[0006]

In the injection molding process, the on and off valves are opened at the vacuum start position almost simultaneously with the start of injection of the injection plunger, and the vacuum tank and the mold cavity are connected to each other. Adjust the degree of vacuum in the mold and discharge the gas in the mold. Then, the ON and OFF valves are closed at the end position, that is, at the stroke end of the injection plunger, and molding is completed.

[0007] If there is a defect in the state of the molded product, if there is a defect, the throttle amount of the variable throttle valve is adjusted, injection molding is started again, and the molded product is confirmed.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a vacuum adjusting device according to the present invention.

FIG. 1 is a perspective view for explaining an outline of an apparatus for adjusting the degree of vacuum in a mold such as a die casting machine.

A mold M is provided with a cavity 1 communicating with an injection sleeve (not shown) as a product, and a chill vent 2 for venting the cavity 1 is provided in the mold M. Vacuum tank 3 connected to vacuum pump P
An on / off valve 8,
A variable throttle valve 4, a filter 6, and a stop valve 7 are provided, the degree of vacuum in the cavity 1 of the mold M of the die casting machine is adjusted, and the gas in the mold is discharged. The variable throttle valve 4 is configured so that the throttle unit can be operated with a manual handle 5 for setting the throttle amount based on the degree of vacuum detected by the vacuum sensor 9, and adjusts the degree of vacuum in a mold such as a die casting machine.

Next, the operation will be described. First, the vacuum pump P is operated, and the stop valve 7 and the on / off valves 8 are opened. The variable throttle valve 4 is manually adjusted based on the measured data in advance.

In the injection molding process, the on and off valves are opened at the vacuum start position, and the vacuum tank and the mold cavity are electrically connected.
The degree of vacuum in the mold is adjusted via a variable throttle valve set to a predetermined throttle amount, and gas in the mold is discharged. During the injection, the degree of vacuum in the cavity 1 is detected by the vacuum sensor 9, and if the degree of vacuum does not reach the predetermined degree, the throttle amount of the variable throttle valve 4 is set again and adjusted until a good product is obtained.

That is, by setting the throttle amount of the variable throttle valve 4, the degree of vacuum detected by the vacuum sensor 9 changes, for example, as a, b, and c as shown in FIG. Select the optimal aperture amount based on the pulling state. As a result, it is possible to suppress casting surface defects or the like due to “pulling” of the molten metal, and it is possible to obtain a cast product with less gas entrainment.

[Embodiment 2] FIG. 2 shows a vacuum degree adjusting device for adjusting the degree of vacuum in the cavity 1 of a die M of a die casting machine. A variable throttle valve 7 detects the degree of vacuum detected by a vacuum sensor 9. The diaphragm unit is operated by the servo motor 11 for setting the diaphragm amount based on the diaphragm amount, and the diaphragm amount is set. The operation is performed in the same manner as in the first embodiment.

That is, by setting the throttle amount of the variable throttle valve 4, the degree of vacuum detected by the vacuum sensor 9 is, for example, as shown in FIG.
As shown in (a), (b) and (c), the aperture amount is selected by the servo motor 11. As a result, it is possible to suppress casting surface defects and the like due to “lead-in” of the molten metal,
A cast product with less gas entrainment can be obtained.

[0016]

As described above, according to the vacuum adjusting device of the present invention, a variable throttle valve is provided in the pipe between the vacuum tank and the vacuum valve without correcting the position of the injection plunger, and the die casting is performed. By adjusting the degree of vacuum in a mold of a machine or the like, it is possible to suppress casting surface defects and the like due to “leading-in” of molten metal.

[0017]

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a first embodiment.

FIG. 2 is a schematic diagram illustrating a configuration of a second embodiment.

FIG. 3 is a diagram showing the degree of vacuum adjusted by the degree-of-vacuum adjusting devices shown in the first and second embodiments.

[Explanation of symbols]

 Reference Signs List 1 cavity 2 chill vent 3 vacuum tank unit 4 variable throttle valve 11 servo motor

Claims (3)

[Claims] 1. A vacuum adjusting device for adjusting a vacuum inside a mold such as a die casting machine, wherein a vacuum start position and an end position in an injection molding process are defined as a start position and a stroke end position of an injection plunger. And a variable throttle valve provided in a conduit between the vacuum tank and the vacuum valve to adjust the degree of vacuum in a mold such as a die casting machine. 2. The vacuum degree adjusting device according to claim 1, wherein the variable throttle valve is a variable throttle valve that manually sets a throttle amount. 3. The vacuum degree adjusting device according to claim 1, wherein the variable throttle valve is a variable throttle valve that sets a throttle amount by a servomotor.