JPH0241750A - Plunger molten metal supplying vacuum die casting device and reduced pressure smelting vacuum die casting device - Google Patents

Abstract

PURPOSE:To reduce gas defect and to improve the quality by connecting a molten metal supplying tube with a plunger sleeve at back side from the waiting position of a plunger tip at the time of reducing the pressure in a device for supplying the molten metal under reducing pressure in a cavity in a die and supplying the molten metal. CONSTITUTION:The plunger tip 4 is stopped at a front position from the molten metal supplying tube 5 and communicated with a vacuum tank 6 and the pressures in the cavity 2 in the die 1 and in the plunger sleeve 3 are reduced. At the time of shifting the tip 4 to the back side from the molten metal supplying tube 5, by difference between the pressure in the sleeve 3 and the atmospheric air pressure, the molten metal is sucked from a melting furnace 8 to supply the molten metal into the sleeve 3. Control of the molten metal quantity is executed by changing stopping time of the tip 4. At the time of supplying the desired quantity of the molten metal, the plunger 4 is pushed and the molten metal is injected, to obtain a product. The outlet of the molten metal supplying tube 5 becomes the atmospheric air pressure and the molten metal is returned back to the melting furnace 8. In such a manner, the supply of the molten metal is facilitated and the gas defect in the product can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vacuum die-casting apparatus that reduces gas defects in products to improve quality, improve die-casting operations, and increase productivity.

[Problems to be solved by conventional technology and invention]

In general, the die casting method is a manufacturing method in which molten metal is filled into a mold at high speed and high pressure and solidified.It has characteristics such as being able to cast thin-walled products and having high dimensional accuracy of the product. It is widely used in fields where large quantities of products are produced.

However, when filling with molten metal, gas from inside the mold tends to get caught up in the molten metal, resulting in gas defects, which cannot be heat treated and cannot be used in areas where strength is required. Ah no ko.

As a method to reduce the occurrence of such gas defects, a vacuum die casting method has been proposed in which molten metal is injected while the inside of the mold is in a vacuum or reduced pressure state.

Typical examples include a method of creating a vacuum inside the mold cavity by installing a vacuum valve in the mold as shown in Japanese Patent Application Laid-open No. 61-273247, and a method of creating a vacuum inside the mold cavity as shown in Japanese Patent Application Laid-Open No. 60-127064. There is a method of attaching a mold waste removal device to the gas vent hole of the mold.

However, with these methods, it is very difficult to time the vacuum suction and injection, and the disadvantage is that the vacuum cannot be drawn sufficiently, and the mold itself has to be machined, which increases the processing cost. The disadvantages include that the device is easily clogged because it comes into direct contact with the molten metal, it is difficult to disassemble and clean, and maintenance is extremely troublesome.

Looking at hot water supply methods, up until now, the most common hot water supply method has been a cold chamber type in which molten metal is supplied to a die-casting machine using a ladle or the like.

Automated equipment has also been proposed, but its basic principle is that it uses a cold chamber and is extremely inefficient when combined with the vacuum die-casting method, which has the disadvantage that its advantages are greatly reduced. Ta.

Furthermore, when aluminum or the like is melted, there is a drawback that hydrogen and the like are dissolved in the molten metal (J included), and when the molten metal solidifies, this hydrogen and the like precipitate and become gas defects.

[Means to solve the problem]

The present invention solves these drawbacks, and its structure will be described in detail with reference to the accompanying drawings as follows.

The plunger hot water supply vacuum die casting device according to the first aspect of the present invention supplies molten metal while reducing the pressure inside the cavity 2 of a mold 1 (fixed mold 1 as a movable mold 11), and uses a plunger displacer 4 in a plunger sleeve 3 to supply molten metal. In a die-casting machine that press-fills molten metal, a hot water supply pipe 5 is connected to a plunger sleeve 3 rearward from a standby position of a plunger tip 4 during depressurization.

The suction pipe 7 connected to the vacuum tank 6 is connected to the plunger sleeve 3 which is forward of the standby position of the plunger tip 4 during depressurization, and the plunger sleeve 3 is connected to the plunger sleeve 3 which is forward of the standby position of the plunger tip 4 during depressurization. A hot water supply pipe 5 may be connected to 3.

Further, the reduced pressure melting vacuum die casting device according to the second aspect of the present invention is a die casting machine that supplies molten metal while reducing the pressure inside the cavity 2 of the mold 1 and press-fills the molten metal with the plunger tip 4 in the plunger sleeve 3. , a hot water supply pipe 5 is connected to the plunger sleeve 3 behind the standby position of the plunger tip 4 during depressurization, and the vicinity of this hot water supply pipe 5 is connected to the melting furnace 8 for melting under reduced pressure by a communication pipe 9, and the plunger The point is that the sleeve 3 is sealed.

[For production]

First, a planner vacuum die-casting apparatus according to the first aspect of the present invention will be explained based on the drawings of FIGS. 1 to 3.

First, the plunger tip 4 is stopped at a position in front of the hot water supply pipe 5, as shown in FIG.

When this state is maintained and communicated with the vacuum tank 6, the pressure inside the cavity 2 of the mold 1 and the inside of the plunger sleeve 3 is reduced via the suction pipe 7.

At this time, since the interior of the hot water supply pipe 5 behind the plunger tip 4 is maintained at atmospheric pressure, molten metal is not sucked from the melting furnace 8.

Next, as shown in FIG. 2, the plunger tip 4 is moved to a position behind the hot water supply pipe 5.

Then, the molten metal is drawn from the melting furnace 8 due to the pressure difference between the pressure inside the plunger sleeve 3 and the atmospheric pressure, and is supplied into the plunger sleeve 3.

The amount of molten metal supplied is controlled by changing the time during which the plunger tip 4 stops.

When a desired amount of molten metal has been supplied, the plunger tip 4 is pressed as shown in FIG. 3 to spray the molten metal and obtain a product.

Also, at this time, the outlet of the hot water supply pipe 5 becomes atmospheric pressure, and the hot water supply pipe 5
The molten metal inside is returned to the melting furnace 8.

Next, a reduced pressure melting vacuum die casting apparatus according to the second aspect of the present invention will be explained based on the drawing of FIG.

First, the plunger tip 4 is stopped at a position in front of the hot water supply pipe 5.

This state is maintained and the metal is melted in the melting furnace 8.

Gas generated when melting the metal is sucked by a vacuum pump 10 connected to the melting furnace 8.

At this time, the end face of the plunger sleeve 3 is sealed so that the atmosphere does not enter the molten metal in the melting furnace 8 which is being melted under reduced pressure through the hot water supply pipe 5.

Further, in order to keep the pressure in the sealed plunger sleeve 3 equal to the pressure in the melting furnace 8, a communication pipe 9 is connected to the vicinity of the hot water supply pipe 5 of the plunger sleeve 3 and the melting furnace 8.

After the melting is completed, the plunger vacuum die casting operation related to the first aspect of the present invention is performed.

〔Example〕

In the drawings, a horizontal cold chamber type die casting machine is shown as the die casting machine, but other types of die casting machines may be used.

In the drawing, a suction pipe 7 connected to a vacuum tank 6 is provided in front of the hot water supply pipe 5 of the plunger sleeve 3, but a vacuum valve or the like may be provided on the mating surface 1c of the mold 1. However, other structures may be adopted as long as they achieve the same effect.

The suction pipe 7 is shown provided above the plunger sleeve 3 to prevent the suction pipe 7 from entering the suction pipe 7 when the plunger tip 4 injects molten metal.

The hot water supply pipe 5 is provided at the upper part of the plunger sleeve 3 so that hot water can be properly supplied into the plunger sleeve 3 and molten metal does not solidify inside the hot water supply pipe 5 when hot water supply is stopped. The case is shown in the figure, but the melting furnace 8
If anti-coagulation measures are taken, the plunger sleeve 3
It may be provided at any position in the circumferential direction.

In the drawing, the structure is such that the excess molten metal in the hot water supply pipe 5 falls into the plunger sleeve 3 after the plunger tip 4 is pressed, but this excess molten metal is removed from the plunger after injection. It is sufficient to eliminate it by moving the chip 4 backward.

The molten metal is supplied from the melting furnace 8 through the plunger tip 4
It may be determined based on the time when the water was in the position where hot water was supplied.

The thickness of the hot water supply pipe 5 is determined in consideration of the molten metal to be poured, the degree of vacuum in the cavity, and the like.

The material of the hot water supply pipe 5 may be a material that is not corroded by the molten metal to be poured, such as a graphite pipe or a ceramic pipe.

It is better to wrap a heater 11 around the hot water supply pipe 5 to prevent the molten metal from solidifying.

The die casting machine is provided with a shift control circuit for controlling the amount of a supplied a and the movement of the plunger tip 4.

In FIGS. 1 and 3, when the plunger tip 4 is in the standby position during decompression, it is in a position forward of the front end of the plunger tip 4, and when the plunger tip 4 is injecting, it is in a position behind the plunger tip 4. A case is shown in which a suction tube 7 is provided at the position.

Instead of the melting furnace 8 described in this specification, a heat retention furnace may be used in which melting is performed in another furnace.

In the reduced pressure melting vacuum die casting apparatus according to the second aspect of the present invention, the pressure inside the melting furnace 8 is always reduced by a vacuum pump 10.

The pressure in the melting furnace 8 when hot water is supplied is set higher than the pressure in the plunger sleeve 3 in a reduced pressure state to enable suction hot water supply.

〔Effect of the invention〕

As described above, the plunger hot water supply vacuum die casting device according to the first aspect of the present invention is a die casting machine that supplies molten metal while reducing the pressure inside the cavity of the mold, and press-fills the molten metal with the plunger depth in the plunger sleeve. Since the hot water supply pipe is connected to the plunger sleeve behind the standby position of the plunger tip during depressurization, the supply of molten metal is controlled only by the forward and backward movements of the plunger tip, and the supply of molten metal is controlled by mechanical movement. It becomes easy to do without parts.

It also becomes easier to time the vacuum suction and injection.

Furthermore, if the suction pipe connected to the vacuum pump is connected to the plunger sleeve in front of the standby position of the plunger tip during depressurization, simply placing the plunger tip in the standby position will remove the inside of the plunger sleeve and the mold cavity. This makes it possible to sufficiently reduce the pressure inside the product, thereby reducing gas defects in the product.

Further, since there is no need to process a mold, it is possible to provide a vacuum die-casting device at a low cost when performing a vacuum die-casting method.

Furthermore, if we look at the hot water supply method, we can see that it is similar to a so-called hot chamber type die-casting machine because the air in the cavity is exhausted and at the same time hot water is automatically supplied by the pressure difference with the heat-retaining furnace. This is the best way to supply hot water.

Furthermore, since the molten metal is automatically supplied into the plunger sleeve due to the pressure difference, the operator does not have to use a ladle or the like to supply hot water, and the die-casting work can be carried out safely.

Furthermore, since the hot water supply pipe can remain in the molten metal of the melting furnace, clean molten metal can be supplied to the die casting machine, thereby providing an excellent plunger hot water supply vacuum die casting device.

As described above, the reduced pressure melting vacuum die casting apparatus according to the second aspect of the present invention is a die casting manon in which molten metal is supplied while reducing the pressure in the cavity of the mold, and the molten metal is press-filled by a plunger tip in a plunger sleeve. A hot water supply pipe is connected to the plunger sleeve behind the standby position of the plunger tip, and the vicinity of this hot water supply pipe is connected to the melting furnace for melting under reduced pressure by a communicating pipe, and the plunger sleeve is sealed, and the die-casting operation is performed. To provide an excellent vacuum die-casting device for melting under reduced pressure, which enables metals such as aluminum to be melted under reduced pressure and prevents gases such as hydrogen from entering the molten metal during melting. It turns out.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a partially sectional front view showing a plunger tip standby state, and FIG. 2 is a partially sectional front view showing a hot water supply state. FIG. 3 is an explanatory front view, partially in section, showing a molten metal injection state, and FIG. 4 is an explanatory front view, partially in section, showing the structure of the reduced pressure melting vacuum die-casting apparatus. DESCRIPTION OF SYMBOLS 1...Mold, 2.Gabity, 3.Plunger sleeve, 4.Plunger tip, 5.Hot water pipe, 6.Vacuum tank, 7.Suction pipe, 8.Melting furnace, 9
Communication pipe. Pufa one

Claims (1)

[Claims] 1. Supplying molten metal while reducing the pressure inside the cavity of the mold,
A plunger hot water supply vacuum die casting machine that press-fills molten metal with a plunger tip in a plunger sleeve, characterized in that a hot water supply pipe is connected to the plunger sleeve behind the standby position of the plunger tip during depressurization. . 2. The plunger hot water supply vacuum die-casting apparatus according to claim 1, wherein a suction pipe connected to a vacuum pump is connected to the plunger sleeve in front of the standby position of the plunger tip during depressurization. 3 Supply molten metal while reducing the pressure inside the mold cavity,
In a die casting machine that presses and fills molten metal with a plunger tip inside a plunger sleeve, a hot water supply pipe is connected to the plunger sleeve behind the standby position of the plunger tip during depressurization, and melting that occurs near the hot water pipe under reduced pressure. A reduced-pressure melting vacuum die-casting device characterized by a plunger sleeve that is sealed and connected to a furnace through a communication tube.