KR102409575B1 - Vacuum module device for improving casting quality - Google Patents

Abstract

The present invention is an apparatus for optimizing the shape of a material by applying a local vacuum pressure to an unformed part of a mold material due to insufficient injection of aluminum molten metal in manufacturing a mold through a general low-pressure casting method. In the general method of injecting molten metal to the top by applying pressure from the bottom of the low-pressure casting mold, this device adds a step of locally applying a vacuum by installing a vacuum module device to increase the injectability of aluminum molten metal, thereby improving productivity by improving material formability and excellent quality can be secured.

Description

Vacuum module device for improving casting quality

The present invention relates to the manufacture of a vacuum module device for low pressure casting, which can efficiently manufacture thin products through a low pressure casting method.

Recently, automotive parts are manufactured using an aluminum casting process to reduce weight. The casting process is a method of producing a product of a desired shape by injecting molten aluminum in a liquid state into a mold. In general, a die casting process and a low pressure casting process are used to manufacture automobile parts. The die-casting process injects molten metal into a mold at a high pressure of 10 to 200 MPa and solidifies it quickly. It has advantages for high dimensional precision and mass production, but there is a limit to the size of products that can be manufactured due to the limitation of the size of domestic production equipment. In addition, in the case of the low-pressure casting process, it is possible to manufacture multiple castings in one cycle by injecting molten metal from the bottom to the top at a pressure of about 800 mbar. Problems such as non-molding cause deterioration of mechanical properties. The vacuum block device, a method that compensates for the shortcomings and problems of this casting method, is a low-pressure casting method that applies vacuum pressure to a local location for product production so that the aluminum molten metal is filled and the pressure is maintained until completely solidified after filling the molten metal. It is a method that can secure excellent quality and is mainly used to manufacture automobile chassis parts. Therefore, the present invention is a mold apparatus for optimizing product production using a low-pressure casting method.

As a related prior art document, there is registered Patent No. 1019060930000. This publication describes a complex vacuum degree calculation method for controlling the vacuum.

The technical problem to be achieved by the present invention is to solve problems such as the difficulty in controlling the local non-formation of products that occur when manufacturing automobile parts of large-sized and thin products through the low-pressure casting method and the local mechanical properties deterioration in the conventional casting method. To this end, we want to manufacture a vacuum module device for low pressure casting.

Low-pressure casting generally injects molten metal up to the top by applying pressure from the bottom.

Accordingly, the present invention locally installs a vacuum block in the mold, and assembles a thin heat-resistant gasket that secondaryly adds compression of the vacuum block between the mold and the vacuum block, and connects the suction pipe to the two holes of the vacuum block. The purpose is to completely fill the molten aluminum in the cavity by applying a vacuum through the suction pipe to form a local vacuum state and transferring the pressure at the bottom to the thin or narrow part, which is the unformed generating part.

The vacuum low-pressure casting mold of the present invention consists of an upper and a lower mold, and the molten metal is injected through the injection hole through which the aluminum molten metal is injected. provides a mold method that injects molten metal from the bottom to the top at a pressure of 700 to 900 mbar, and applies a second vacuum to inject the molten metal to the point where the molten metal cannot be filled only by pressurization to produce products in a vacuum pressurization method. .

In the above, a gas hole is machined on the upper mold to form a cavity for injecting molten aluminum, and a vacuum block having a suction hole through which a local vacuum pressure can be applied through the gas hole is machined;

A gasket for sealing the vacuum block and

A suction pipe that is connected to the vacuum block and sucks the vacuum pressure;

When the molten metal is filled in the mold, it provides an apparatus comprising a control device for applying a local vacuum pressure until the molten aluminum reaches the narrow and thin parts in the mold and solidifies.

The vacuum block is

It is assembled in a mold with gas holes and has two suction holes and an assembly hole that can be assembled with the mold. It is a device that sucks a local vacuum through the suction hole. As a result of analyzing the air pressure and filling pressure according to time, It is a device that can apply vacuum by adding local pressure during vacuum suction by locating the optimized Φ16, 2 holes that do not apply back pressure during suction.

The gasket is

It is a ceramic gasket made of heat-resistant sealing material that can withstand more than 900℃, and it is a device that presses between the vacuum block and the mold to add the compression of the vacuum block.

It is joined to the mold part at the assembly position of the vacuum block in a flat shape and the lower surface of the vacuum block,

The vacuum block has a ring shape wrapped around the periphery of the cross-sectional area for pressing the mold, and is formed to have a height of 2 mm and a thickness of 1 mm to enhance vacuum suction and add compression.

The suction pipe (Pipe),

It connects between the vacuum block and the vacuum device and becomes a passage that can apply local vacuum pressure,

It is a tube-type pipe device that has an inner diameter of Φ16 and a thickness of 2mm and is connected to the suction hole of the vacuum block to suck a local vacuum.

That is, the present invention is

A vacuum low pressure casting mold apparatus comprising:

Comprising an upper mold and a lower mold, and a sleeve for injecting molten metal into the lower mold,

the sleeve lower portion is arranged in a pressing device,

The upper mold includes a plurality of gas holes at the upper part of the upper mold to vacuum suction the gas in the cavity;

A vacuum block communicating with the gas hole and closely coupled to the surface of the body of the upper mold to which a suction pipe connected to a vacuum device is connected; including,

First, the molten metal is filled into the cavity by pressurization,

Provide a vacuum low-pressure casting mold apparatus characterized in that the molten metal is filled to a point not reached by the primary filling by pressure by vacuum suction through a suction pipe connected to the vacuum block in a state of maintaining the pressure do.

In the above, it is arranged on the lower periphery of the vacuum block and helps to seal the vacuum block, a gasket of an annular shape according to the shape of the periphery of the vacuum block; provides a vacuum low-pressure casting mold apparatus, characterized in that it further comprises .

In the above, the prize mold,

The end of the cavity formed by the upper mold has a cemented portion so that the molten metal does not rise any more;

a plurality of gas holes formed in a margin portion extending outwardly of the bonding portion;

a porous vent connected to each gas hole; and

One end is connected to the porous vent and the other end includes a connecting pipe arranged inside the vacuum block body,

The cementation part has a gap through which the molten metal cannot pass, so that when vacuum is sucked, the gas moves to the gap, the gas hole, the porous vent, the connecting pipe and the suction pipe connected to the vacuum block and vacuum is sucked. Molding equipment is provided.

In the above, comprising a vacuum control unit for controlling vacuum suction, wherein the vacuum control unit is controlled to apply a local vacuum pressure until the molten metal reaches the narrow and thin portions in the mold cavity and solidifies. A casting mold apparatus is provided.

In the above, the vacuum block includes two or more assembly holes and a suction hole to which the suction pipe is connected so that it can be assembled in the upper mold, and the diameter and number of the suction holes are determined according to the size and shape of the molded product and the simulation result It is designed to be controlled, and the simulation provides a vacuum low-pressure casting mold apparatus, characterized in that it is optimized so that back pressure does not occur during vacuum suction as a result of analyzing the gas pressure and the molten metal filling pressure according to time.

In the above, the gasket provides a vacuum low-pressure casting mold apparatus, characterized in that it contains a heat-resistant ceramic material that can withstand a temperature of 900 °C or higher.

In the above, the primary pressure range is 700 to 900 mbar, and the vacuum suction force provides a vacuum low-pressure casting mold apparatus, characterized in that it is adjusted for each casting in the range of -1 to -5 kPa.

In the above, there are two suction holes, and the diameter of the suction holes is 10 to 20 mm to provide a vacuum low-pressure casting mold apparatus.

According to the present invention, the inside of the mold cavity can be completely filled with the molten metal by applying a vacuum through the suction pipe to form a local vacuum state. That is, only the pressure applied from the conventional lower mold side can fill the molten aluminum by vacuum suction of the present invention to the thin or narrow portion, which is the non-forming portion, thereby improving the casting quality. As a result, it is possible to obtain positive effects such as securing excellent quality, high casting recovery rate, and improving productivity in the production of large-scale and thin automobile products, which are global trends.

1 is a schematic diagram of a vacuum / pressure hybrid casting method aluminum molten metal injection method.
2 is a schematic diagram of a vacuum module device;
3 and 4 are assembly views of a vacuum module device.
5 is a vacuum flow diagram of a vacuum module device.
6 is a diagram of a vacuum block and gasket.
7 is a diagram of vacuum module device analysis conditions.
8 is an analysis diagram of the filling pressure according to the time of the vacuum module device.
9 is an air pressure analysis diagram according to the vacuum module device time.
10 is a flow line distribution diagram of a vacuum module device.
Fig. 11 is a diagram showing results of analysis of a vacuum module device;
12 is a photograph showing a comparison of the forming part before and after operation of the vacuum module device.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram of a vacuum / pressure hybrid casting method aluminum molten metal injection method. In order to fill the molten metal into the cavity formed by the upper mold and the lower mold, a pressing stroke for raising the molten metal is performed on the sleeve side connected to the lower mold, and the molten metal enters the cavity primarily. That is, a pressing device capable of pressing the molten metal is configured below the lower mold, and a sleeve connected to the lower mold is arranged in the pressing device.

Next, in a pressurized state, a suction pipe is connected to a gas hole formed in the upper mold to perform vacuum suction to further raise the molten metal, and the vacuum degree is further increased to further increase the rise of the molten metal to completely fill the inside of the cavity. This vacuum/pressure hybrid molten metal injection method has the effect of completely filling the molten metal up to the thin part or the narrow part.

For vacuum suction type molten metal filling, vacuum suction power needs to be transmitted to the cavity without leakage, and back pressure should not occur. Accordingly, the present invention constitutes a porous vent extending from a hole for vacuum formed in the upper mold and a vacuum block covering them, and a suction hole 155 formed like two suction branches arranged at a predetermined interval in the vacuum block. ) was constructed with a suction pipe. In addition, a gasket for sealingly covering the lower end of the vacuum block is arranged in order to thoroughly prevent leakage of the vacuum suction force. The gasket is a ceramic gasket, made of a heat-resistant sealing material capable of withstanding 900° C. or higher, and is a device for pressing between the vacuum block and the mold in order to further compress the vacuum block. It is bonded to the lower surface of the vacuum block, and has a ring shape that is wrapped around the periphery of the cross-sectional area where the vacuum block compresses the mold, and is formed to have a height of 2 mm and a thickness of 1 mm to enhance vacuum suction and add compression force.

2 is a schematic cross-sectional view of the vacuum module device of the present invention.

As described above, the vacuum block 100 covering the plurality of gas holes in the cavity 30 formed by the upper mold 10 side and the porous vent (to be described later) part connected thereto and the lower surface of the vacuum block around the upper mold surface and A gasket 120 for contacting and sealing is arranged, and the suction pipe 150 is configured to include two suction holes 155 on the top surface of the vacuum block at a predetermined interval. The diameter of the suction hole is 10 to 20mm, preferably, it is designed to be Φ16, and two or more suction holes may be configured, and the number may be custom designed according to the size, volume, and shape of the molded article. It is designed with reference to the simulation results for vacuum suction.

Figure 3 shows a part of the vacuum module in a cross-sectional view, Figure 4 is shown in a partially cut-away perspective view.

5 is an arrow indicating the flow of airflow according to vacuum suction by the vacuum module.

6 is a plan view and cross-sectional view of a vacuum block and a gasket, a suction pipe is connected to the upper surface of the vacuum block, and the gas holes of the upper mold and the porous vents connected to each of the gas holes are covered to transfer the vacuum suction force into the cavity. In addition, the vacuum block has an assembly hole 170 that can be assembled with the mold.

That is, the vacuum block has at least two suction holes 155 and an assembly hole 170 through which a suction pipe is connected to the block and passes through the vacuum block body, and the inside of the vacuum block body is a vacuum block peripheral portion 180 to which the gasket is to be coupled. ), it is processed to have a recessed space inside. The ends of the connecting pipes 130 connected to the gas hole 110 and the vent 125 provided in the mold are arranged in the space inside the body of the vacuum block, and the gasket is arranged along the circumference of the vacuum block to receive the vacuum block as a prize. It is sealed in contact with the upper surface of the mold.

The vacuum module thus constructed enables vacuum/pressure hybrid casting as described above.

7 is a diagram of vacuum module device analysis conditions, and shows the vacuum module part and process conditions in more detail and schematically. Although the bottom of the gasket is in contact with the surface of the mold, the mold surface joined to the bottom of the gasket is omitted in FIG. 7 .

A plurality of gas holes 110 are formed at substantially constant intervals on the upper surface of the upper mold 10 , and a porous vent 125 is connected to the gas holes 110 . The porous vent 125 is composed of a porous rod including micropores, so that the gas can move by vacuum suction, but the molten metal does not pass through.

The pressing condition can be controlled in a very wide range according to the size, shape, and thickness of the molded article. After filling the molten metal under the primary pressure condition of 700 to 900 mbar (preferably 800 mbar), vacuum suction is performed while maintaining the pressure condition as it is. With vacuum suction, molten metal can be injected to the point where the molten metal cannot be filled only by pressurization.

The cavity end 35 formed by the upper mold 10 has a cemented shape so that the molten metal does not rise any more, and gas holes 110 are formed in a margin portion extending outward therefrom. Even when the cavity end 35 is formed in a cemented form, the gas can pass through the gap and can be vacuum-sucked. A porous vent 120 having a diameter of 1 to 3 mm and a height of 5 to 15 mm is connected to the hole 110, and a pipe 130 (diameter of 4 to 8 mm) is preferably connected to the vent 120, and vacuum The block covers them all, and the rim of the vacuum block is sealed with a gasket. The vacuum suction force can be adjusted for each casting in the range of -1 to -5 kPa.

On the other hand, when the molten metal is filled, a vacuum control device is included that applies a local vacuum pressure until the molten aluminum reaches the narrow part and the thin part in the mold and solidifies.

8 is an analysis diagram of the filling pressure according to the time of the module device, and it can be seen that the molten metal can be uniformly filled in the cavity within a short time by computer simulation.

9 is an analysis diagram of air pressure according to time of the vacuum module device, and it can be seen that the cavity is uniformly evacuated within a short time.

10 is a flow line distribution diagram of a vacuum module device. According to the configuration of the present invention, it can be predicted that a vortex is hardly formed due to vacuum suction, so that it is advantageously designed to fill the cavity of the molten metal.

11 is a vacuum module device analysis result diagram, when vacuum is sucked, flow rate increases and pressure is strengthened due to reduction of the vent cross-section, air movement occurs so that the deviation of the air behavior is not large in each vent, and the suction pipe having two suction holes It can be seen that the configuration rarely causes backpressure problems. The two pipes are arranged symmetrically about the center of the total length of the part.

12 is a photograph showing a comparison of the molded part before and after operation of the vacuum module device, and clearly shows that a much better casting can be obtained when vacuum suction is performed.

Although the embodiment of the vacuum module has been described with respect to the casting apparatus including the upper and lower molds, it may be applied even when a single mold is used.

Unless otherwise defined in the foregoing, all technical and scientific terms used herein have the same meaning as commonly understood by a person skilled in the art to which this invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless specifically defined explicitly. In the entire specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated. Also, the singular may include the plural by context.

The right of the present invention is not limited to the above-described embodiments, but is defined by the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. it is self-evident

10: prize money
30: cavity
35: cavity end
100: vacuum block
110: gas hole
120: gasket
125: vent
130: pipe
150: suction pipe
155: suction hole
180: vacuum block perimeter

Claims (8)

A vacuum low pressure casting mold apparatus comprising:
Comprising an upper mold and a lower mold, and a sleeve for injecting molten metal into the lower mold,
the sleeve lower portion is arranged in a pressing device,
The upper mold includes a plurality of gas holes at the upper part of the upper mold to vacuum suction the gas in the cavity;
A vacuum block communicating with the gas hole and closely coupled to the surface of the body of the upper mold to which a suction pipe connected to a vacuum device is connected; including,
First, the molten metal is filled inside the cavity by pressurization,
In the state where the pressure is maintained, the molten metal is filled to a place not reached by the primary filling by pressure by vacuum suction through the suction pipe connected to the vacuum block secondarily,
The prize money is
The end of the cavity formed by the upper mold has a cemented portion so that the molten metal does not rise any more;
a plurality of gas holes formed in a margin portion extending outwardly of the bonding portion;
a porous vent connected to each gas hole; and
One end is connected to the porous vent and the other end includes a connecting pipe arranged inside the vacuum block body,
Ends of the connecting pipes are arranged in the space inside the body of the vacuum block,
Including; is arranged on the periphery of the lower end of the vacuum block to help the sealing of the vacuum block, an annular gasket according to the shape of the periphery of the vacuum block;
The cementation unit has a gap through which the molten metal cannot pass, and when vacuum is sucked, the gas moves to the gap, the gas hole, the porous vent, the connecting pipe, and the suction pipe connected to the vacuum block, and vacuum is sucked. casting mold device.
delete delete According to claim 1, comprising a vacuum control unit for controlling vacuum suction, wherein the vacuum control unit is controlled to apply a local vacuum pressure until the molten metal reaches the narrow and thin portions in the mold cavity and solidifies. Vacuum low pressure casting mold device. According to claim 1, wherein the vacuum block comprises two or more assembly holes and a suction hole to which the suction pipe is connected so as to be assembled in the upper mold, the diameter and number of the suction holes are the size and shape of the molded product and simulation results The vacuum low-pressure casting mold apparatus, characterized in that the gasket is arranged so that back pressure does not occur during vacuum suction as a result of analyzing the gas pressure and the molten metal filling pressure according to the time of the simulation. The vacuum low-pressure casting mold apparatus according to claim 1, wherein the gasket includes a heat-resistant ceramic material capable of withstanding a temperature of 900°C or higher. 5. The vacuum low-pressure casting mold apparatus according to claim 1 or 4, wherein the primary pressure range is 700 to 900 mbar, and the vacuum suction force is adjusted for each casting in the range of -1 to -5 kPa. The vacuum low-pressure casting mold apparatus according to claim 5, wherein there are two suction holes, and the diameter of the suction holes is 10 to 20 mm.

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