JPH0811281B2 - Vacuum die casting equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vacuum die-casting apparatus capable of improving the quality by eliminating defects caused by blowholes in products.

[Problems to be Solved by Prior Art and Invention]

Generally, casting by a die casting machine is widely used as a method for manufacturing a large amount of precision products, but this type of casting fills the molten metal into the mold at high speed and high pressure, so that the gas in the cavity is filled. If it is left to natural exhaust, the replacement of the molten metal with the gas will be incomplete, and the gas entrainment phenomenon will occur, causing blowhole defects, which may result in defective products.

Therefore, in the conventional die casting machine of this type, as shown in FIG. 2, a vacuum valve is provided in a part of the gas release passage of the mold, and a vacuum pump connected in communication through the vacuum valve is used to control the inside of the cavity. A method has been proposed in which gas is forcibly exhausted, the vacuum valve is closed when the molten metal fills the cavity, and a desired pressing force is applied to the molten metal to obtain a product of good quality.

However, in the method of casting by forcibly exhausting from the mold side using the vacuum valve as described above, the mechanism becomes complicated and the valve mounting position is restricted, so the position of the gas vent can be set freely. There is a drawback that can not be done.

Further, there is a drawback in that the valve is likely to be clogged when it comes into direct contact with the molten metal, and it is also difficult to disassemble and clean and maintenance is extremely troublesome.

The present invention provides a vacuum die casting apparatus whose technical problem is to solve such drawbacks.

[Means for solving the problem]

 The gist of the present invention will be described with reference to the accompanying drawings.

A die casting machine 5 for injecting a molten metal into a plunger sleeve 2 communicating with the die 1 and press-fitting the molten metal into a cavity 4 of the die 1 by a plunger 3, which is a hot water supply port 13 of the plunger sleeve 2. A vacuum chamber 6 is attached to the outside of the mold to keep the airtight state, and a vacuum pump 7 for depressurizing the cavity 4 of the mold 1 and a water heater 8 for injecting the molten metal into the plunger sleeve 2 are provided in the vacuum chamber 6. The hot water supply pipes 14 of the hot water supply device 8 are vertically connected to the inside of the vacuum chamber 6 from the upper wall of the vacuum chamber 6, and the lower end of the hot water supply pipe 14 is provided at the hot water supply port 13 and located on the upper wall of the vacuum pipe 6. Heater 17 on hot water supply pipe 14
The present invention relates to a vacuum die casting device characterized by being attached.

[Action]

When the vacuum pump 7 is operated, the vacuum chamber 6 disposed outside the plunger sleeve 2 is decompressed, and the interior of the plunger sleeve 2 and the cavity 4 of the mold 1 are exhausted and decompressed through the hot water supply port 13. .

In this state, the hot water supply pipe 14 of the hot water supply device 8 attached to the vacuum chamber 6
A desired molten metal is poured into the plunger sleeve 2 through the hot water supply port 13 of the O-ring 12, and the filled molten metal is pushed into the cavity 4 of the mold 1 by the plunger 3. Press-fit and fill with to make a product.

At this time, the heater 17 heats the hot water supply pipe 14 outside the vacuum chamber 6 of the hot water supply device 8 to improve the hot water supply.

〔Example〕

A die casting machine 5 in the drawing shows a case where a horizontal cold chamber die casting machine is adopted. Molten metal is injected into a plunger sleeve 2 communicating with the die 1, and the molten metal is injected by the plunger 3 into the die 1 Is a die-casting machine 5 for press-fitting and filling into the cavity 4 of the mold 1, in which a vacuum chamber 6 is attached to the outside of the hot water supply port 13 of the plunger sleeve 2 and the cavity 4 of the mold 1 is attached to the vacuum chamber 6. A vacuum pump 7 for depressurizing the inside and a hot water supply device 8 for injecting molten metal into the plunger sleeve 2 are connected to each other, and a hot water supply pipe 14 of the hot water supply device 8 is hung from the upper wall of the vacuum chamber 6 into the vacuum chamber 6. The lower end of the hot water supply pipe 14 is provided in the hot water supply port 13, and the heater 17 is provided on the hot water supply pipe 14 located on the upper wall of the vacuum pipe 6.
The present invention relates to a vacuum die casting device additionally provided with.

It is desirable that the mating surface 11 between the movable die 9 and the fixed die 10 should be sealed with an O-ring 12 or a gasket to prevent air from leaking into the cavity 4 to be depressurized.

The mating surface between the plunger sleeve 2 and the vacuum chamber 6 may be sealed with an O-ring 12.

The vacuum chamber 6 has a plunger sleeve 2 for maintenance and the like.
It is desirable to adopt a structure that can be easily attached to and detached from.

The water heater 8 is shown in the drawing as a plunger sleeve 2
Hot water supply pipe 14 located above the hot water supply port 13
Shows a case where the vacuum chamber 6 is hung vertically in the vacuum chamber 6.
The thickness of the hot water supply pipe 14 may be set in consideration of the molten metal to be cast, the degree of vacuum in the cavity 4, and the like.

In the figure, reference numeral 15 is a heat-retaining furnace that melts the material to be cast or keeps it at a high temperature, and 16 is a valve device that controls hot water supply.

A motor 17 is attached around the hot water supply pipe 14 so that the molten metal does not solidify so that the molten metal can be poured well.

The drawing shows a vacuum type for checking the degree of vacuum in the vacuum chamber 6.
Reference numeral 18 shows a case where a leak valve 19 for returning the inside of the vacuum chamber 6 to the atmospheric pressure is provided.

In order to accelerate the casting cycle, a leak valve 20 for returning only the inside of the cavity 4 to the atmospheric pressure may be provided on the mating surface 11 between the movable mold 9 and the fixed mold 10.

〔The invention's effect〕

As described above, according to the present invention, a vacuum chamber is provided outside the plunger sleeve without exhausting air from the mold side, and a hot water supply pipe is vertically provided in the vacuum chamber to supply hot water to the hot water supply port of the plunger sleeve. Since it is configured as described above, the mechanism is simple and the inside of the cavity can be easily depressurized, and the die casting machine can manufacture a product of excellent quality without the occurrence of blow holes.

In addition, since it is not necessary to provide a gas vent hole for discharging the gas in the cavity in the mold, it is possible to reduce the number of steps when manufacturing the mold, and the mold can be manufactured at low cost. However, the product has a good yield when casting.

Furthermore, since a heater is attached to the hot water supply pipe that is hung vertically in the vacuum chamber and is located on the outer wall of the vacuum pipe of the hot water supply pipe to heat the molten metal, the molten metal does not solidify and is poured very well. In addition, since there are few parts that come into direct contact with the molten metal, the vacuum die-casting device has excellent practical effects such as easy valve cleaning and extremely simple maintenance.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is an explanatory view of the present invention with a partial cross section, and FIG. 2 is an enlarged cross-sectional view of a gas vent in a conventional example. 1 ... Mold, 2 ... Plunger sleeve, 3 ... Plunger, 4 ... Cavity, 5 ... Die casting machine, 6 ... Vacuum chamber, 7 ... Vacuum pump, 8 ... Hot water supply device, 13 ... … Hot water supply port, 14… Hot water supply pipe, 17… Heater.

Claims (1)

[Claims] 1. A die casting machine for injecting a molten metal into a plunger sleeve communicating with a die, and press-filling the molten metal into a cavity of the die by a plunger.
A vacuum chamber is attached to the outside of the hot water supply port of the plunger sleeve to keep it airtight, and a vacuum pump for depressurizing the mold cavity and a water heater for injecting molten metal into the plunger sleeve are connected to this vacuum chamber. Then, the hot water supply pipe of the hot water supply device is hung from the upper wall of the vacuum chamber into the vacuum chamber, and the lower end of this hot water supply pipe is installed in the hot water supply port, and a heater is attached to the hot water supply pipe located on the upper wall of the vacuum pipe. Characteristic vacuum die casting equipment.