KR100349616B1 - Vacuum Permanent Mold Casting Equipment - Google Patents

Abstract

In order to seal the casting mold by vacuum, a ring is installed on the joint surface of the mold, the upper mold and the lower mold to seal the mold, and an “O” ring is also installed on the joint surface between the mold, the lower mold and the plate to melt the molten metal. It is completely filled in the casting cavity, resulting in a relatively complete casting casting without bubbles and unforming.

Description

Vacuum gravity casting {Vacuum Permanent Mold Casting Equipment}

The present invention relates to a vacuum gravity casting method for preventing gas and air from being mixed in a molten casting in a gravity casting operation.

Generally, air and gas in the cavity of the casting mold are removed by the casting mold parting, the riser, and the air vent, but air and gas are not completely removed. It did not prevent incorporation.

In other words, if air and gas in the casting mold cavity are not mixed in the molten metal, bubbles can be prevented. If there is no air and gas pressure in the cavity, the thin part is completely filled to prevent unmolding, thus making a complete casting product. However, in the case of the prior art, as gas and air are mixed in the molten metal, bubbles generated in the main part cause problems such as unmolded parts that are incompletely filled in thin parts, so that bubbles appear during machining. In addition, product leakage has frequently occurred due to pressure leakage problems. As a result, problems such as deterioration of product quality, increase of inspection cost, and increase of reprocessing cost have occurred.

In order to solve this problem, the present invention is directed to solving this problem by injecting molten metal into a mold cavity.

To this end, the present invention has devised a means capable of sealing all the bonded portions in each component of the mold, and also a process treatment means for sealing.

1 is a schematic illustration showing a vacuum gravity casting process according to the present invention.

2 is a cross-sectional explanatory view of the sealing mechanism of the casting mold partition surface according to the present invention.

3 is an explanatory view of a sealing mechanism sealing the mold and the sealing plate according to the present invention.

(Key sign)

2.Inlet opening and closing device 3,4. Upper and lower molds of casting molds

5.Cavity 6.Mill Pin 7.Mill Plate 8.Valve

9.Vacuum tank 11.Casting die face 13. Groove 14.O-ring C

That is, in the present invention, the casting mold cavity is vacuumed, and a sealing device is installed in the casting mold, and an "O" ring is installed on the joining surfaces of the mold, the upper mold, and the lower mold to seal the mold, and is sealed at the inlet. Of the switchgear, and the airtight device is also attached to the mil pin area.

At this time, it is important to remove the moisture in the air, which causes bubbles, by preheating and drying in parallel with vacuum before pouring molten metal into the mold.

Valves are installed at the air and gas outlets to be connected to the vacuum tank, and the vacuum pump is connected to the vacuum tank, and the inside is vacuumed.

Next, when the molten metal is poured into the inlet and the inlet opening / closing device is opened, the molten metal enters the mold cavity to completely fill the space, and when the mold is opened after the solidification, the product is opened and the product is free of bubbles and unformed products.

The present invention will be described in more detail with reference to the drawings.

1 is a schematic illustration showing a vacuum gravity casting process according to the present invention.

2 is a cross-sectional explanatory view of a closed mechanism of the casting mold partition surface according to the present invention.

3 is an explanatory view of a sealing mechanism sealing the mold and the sealing plate according to the present invention.

As shown in FIG. 1, in the vacuum gravity casting of the present invention, an inlet opening and closing device (2) capable of adjusting an up and down distance is provided at an inlet part of an upper mold (3) and a lower mold (4) of a casting mold, and a valve is provided at the outlet thereof. (8) and the next vacuum tank 9 and the vacuum pump 10 are connected in series so as to seal the cavity 5 space in the mold.

Here, even if the mold makes the cavity 5 in the casting mold into a vacuum through the vacuum tank 9, if the casting mold cavity 5 is not sealed, there is no vacuum effect. (6) must be sealed.

2 shows the sealing mechanism of the dividing surface 11, in order to seal the casting mold dividing surface 11 between the upper mold 3 and the lower mold 4 of the mold before the molten metal is injected into the cavity 5; It is covered with a seal 12 made of an elastic material such as a heat-resistant rubber or a sheet.

In addition, FIG. 3 shows that the casting mold dividing surface 11 and the mill pin portion 6 are completely sealed by attaching an 'O' ring 14 to an appropriate place between the mold lower die 4 and the mill plate 7. It gives a sealing function.

Here, the 'O' ring is ring-shaped or spherical, and the groove 13 is formed above and below the surface of the appropriate place between the mold lower die 4 and the mill plate 7, and the ring-shaped or After inserting the 'O' ring as a spherical elastic body and assembling it with a little pressure, the mold lower mold and the sealing plate can be completely sealed.

Preheat-dry the mold to 150 ℃ ~ 550 ℃ according to the sealed mold thickness and the type of casting products as above. (3) (4) Apply DieCoat with spray spray or brush and dry it again. Combine the molds.

Next, after closing the inlet opening and closing device 2 to seal the molds 3 and 4, the valve 8 between the mold and the vacuum tank is opened to vacuum the inside of the mold cavity. The vacuum at this time is commercially set at approximately -1000 mbar to -950 mbar, and the vacuum in the cavity is thus approximately -700 mbar to -500 mbar, and at least a vacuum of at least -500 mbar is required for good working conditions.

After injecting the molten metal through the inlet, injecting the molten metal into the mold cavity 5 by opening the injector opening and closing device 2, the casting product is withdrawn from the mold when the inlet solidifies.

The vacuum gravity casting method of the present invention having the above-described configuration is as follows.

That is, as shown in FIG. 1, the vacuum gravity casting first closes the valve 8 and sucks air in the cavity 5 with the vacuum pump 10 to make the vacuum tank 9 into a vacuum.

Then, the mold upper die 3 and the lower mold die 4 are combined, the inlet opening and closing device 2 is closed, and the valve 8 is opened. The mold cavity 5 is connected to the vacuum tank 9 to become a vacuum.

Next, when the molten metal is poured into the inlet 1 and the inlet opening and closing device 2 is opened, the molten metal is filled and filled into the cavity 5 at a short distance. When the molten metal is completely filled in the mold, the valve 8 is opened. Lock and vacuum the tank (9) with a vacuum pump (10).

When the molten metal cools and becomes solid, the upper mold 3 and the lower mold 4 of the mold are separated, and the cast product is pushed up using the peel pin 6 to take out the solidified product from the mold.

The casting product is removed from the mold, the upper mold (3) and the lower mold (4) are combined together, the inlet opening and closing device (2) is closed, and the inlet (1) is poured into the casting product. When casting is performed while repeating these operations, the product is manufactured without casting bubbles and having a clean surface.

EMBODIMENT OF THE INVENTION Below, an Example is given and described in order to demonstrate this invention more concretely.

The casting mold was preheated and dried at 260 ° C to obtain an aluminum casting with a thickness of 5mm. Then, the inlet opening and closing device immediately before the mold was opened and 650 ° C. aluminum molten metal was injected.

About 6 minutes after the injection of the molten metal, the product in the mold was withdrawn and the aluminum casting product was randomly cut and examined for appearance. All 10 casting products had no bubbles at all, and the surface was burned. Burnt surface and the like, as well as no thin film or scratch on the surface.

According to the present invention, bubble generation, which is most problematic in non-ferrous castings such as aluminum and copper castings, as well as general castings and steel castings, is hardly seen, and breakthroughs can be suppressed.

Claims (2)

In the vacuum gravity casting method, which mainly consists of a mold, a vacuum tank and a vacuum pump, which are fitted into an upper mold and a lower mold, An inlet opening and closing device is installed at the inlet of the mold, and an air flow control valve, a vacuum tank, and a vacuum pump are serially connected to the outlet of the mold to form a vacuum state by sealing a cavity space in the mold. In order to seal the cavity space, the upper and lower molds of the mold are covered with a ring or sheet of elastic rubber before the injection of the molten metal, and grooves are formed in the upper and lower surfaces between the lower mold and the lower plates of the mold. After inserting the 'O' ring made of a ring-shaped or spherical elastic material into this groove, the mold is assembled and the mold opening is closed to seal the mold. The casting mold in which the cavity space is sealed is preheated and dried at 150 ° C. to 550 ° C. according to the thickness, and then coated with a die coat, and dried again, and then the upper and lower molds are combined to work. Opening the valve between the vacuum tank to the vacuum in the mold cavity, the vacuum gravity casting method characterized in that the vacuum in the mold cavity is set to -500mbar or more. delete