JPH0343933B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a casting method and a casting device thereof, and more particularly, the degree of vacuum is improved by improving the timing and conditions when starting the vacuum, and the molten metal is heated. The present invention relates to a casting method and device equipped with a degassing method and device for reliably removing contained gases (mainly air).

[Prior Art] This type of casting apparatus, for example, a vacuum casting apparatus, generally has a plunger tip slidably housed in a sleeve having a hot water supply port at one end, and the other end of the sleeve is inserted through a gate. The plunger tip is connected to the cavity formed between the dies after the mold is closed, and the molten metal supplied from the hot water supply port is sent into the cavity through the gate, and when the molten metal is solidified in the cavity, the molten metal is The structure is such that the cavity and sleeve are evacuated before being fed into the chamber.

Conventionally, as shown in Figs. 1 to 4, mold closing (Fig. 1) and hot water supply (Fig. 2) were performed one after the other, and the plunger tip was advanced to block the hot water supply opening. The first injection was performed (Fig. 3), the hot water supply port was closed, and a vacuum was drawn from the vacuum passage communicating with the cavity (Fig. 3), and the molten metal was sent into the cavity by the second injection.

Other prior art is described in Japanese Patent Publication No. 51-25805. This device has a hot water tap installed over the hot water supply port of the sleeve that connects one end to the mold cavity, which is evacuated to create a vacuum state before molten metal is introduced, and opening/closing devices installed at the top and bottom openings of this hot water tap. It is of structure.

[Problems to be solved by the invention] According to the conventional general vacuum casting method as described above, the air inside the large volume sleeve is once drawn into the cavity through the gate of the narrow passage that communicates the sleeve and the cavity. Since the cavity is evacuated after being drawn in, it takes a long time to achieve the target degree of vacuum in the cavity. If the process takes a long time, it will take a long time to complete one process, making it difficult to reduce costs through mass production, and there are many inconveniences such as the molten metal cooling down and adversely affecting the quality of the product.

Therefore, in order to shorten the evacuation time, as shown in FIG. Improvements can be considered that would make it more attractive.

However, even with these improvements, the evacuation time is only slightly shortened, which is the same as the conventional method described above, and because priority is given to shortening the working time of one process, it is not possible to do so as expected. The degree of vacuum has not improved.

As a result, the air inside the sleeve enters the cavity together with the molten metal through the gate, causing cavities in the product (molded product) and deteriorating the quality of the product.

Furthermore, even if the above-mentioned defects in evacuation are resolved and sufficient evacuation can be achieved, the next problem will be that there is air dissolved or remaining in the form of bubbles in the molten metal. I'm getting old. Therefore, it becomes necessary to extract the gas content from the molten metal as well.

Furthermore, in the device described in the above publication (Japanese Patent Publication No. 51-25805), during hot water supply, the upper opening/closing device of the receiver attached to the sleeve is opened to the outside, and after supplying molten metal to the receiver, the upper opening/closing device is opened. After the equipment is closed, the gas in the molten metal is evacuated, and then the lower opening/closing device is opened to supply hot water into the sleeve. It is necessary to create a vacuum inside the hot water tank. For this reason, it takes an extremely long time to create a vacuum inside the water pan. In addition, the molten metal supplied to the receiving metal remains in a fixed amount, and only the surface of the molten metal comes into contact with the vacuum area, so the gas content in the molten metal cannot be completely extracted, and the efficiency is low. It takes a very long time to release the gas. Furthermore, as mentioned above, it takes time to create a vacuum inside the trough, and it also takes time to degas the molten metal supplied into the trough, so casting work and degassing the molten metal must be done at the same time. Because it is not possible to do this, work is done in batches, resulting in low productivity.

The present invention has been made in view of the above-mentioned points. For example, in vacuum casting, the condition and timing of starting evacuation are improved, and in other words, when hot water is supplied from the hot water inlet, which takes a relatively long time, To provide a casting method and casting device that can sufficiently increase the degree of vacuum without increasing the time of one process by creating a situation where vacuuming can be performed in parallel, thereby eliminating the need for a particularly long time just for vacuuming. It is intended to.

[Means for Solving the Problems] In order to achieve the above object, the casting method of the present invention includes injecting molten metal into the sleeve from a hot water supply port provided at one end of the sleeve, and then storing the molten metal in the sleeve. In a casting method in which a plunger tip is introduced to feed molten metal into a cavity, and the molten metal is solidified within the cavity to perform casting, before injecting the molten metal into the sleeve from the feed port, the molten metal is poured into a previously emptied container. After a certain amount of molten metal is injected and dropped while being isolated from the outside air and the inside of the sleeve to remove gas, the hot water supply port is opened and the molten metal in the container is injected into the sleeve.

Further, the casting apparatus of the present invention for carrying out the above method is comprised of a sleeve having a hot water supply port at one end and a plunger tip housed within the sleeve, and the gate is inserted from the other end of the sleeve. In a vacuum casting apparatus in which molten metal is fed into a cavity formed between both molds through a mold, a water heater is connected to the hot water supply port, and this water heater communicates with the hot water supply port, but is not connected to the inside of the vacuum container. The water heater has an on-off valve type hot water supply container that rotates between two positions: a hot water supply position that does not communicate with the vacuum container, and a hot water receiving position that communicates with the inside of the vacuum container but does not communicate with the hot water supply port. A vacuum container further equipped with a vacuum passage is installed above the vacuum container, and at the upper end of this vacuum container,
A second water heater that injects molten metal into the vacuum container is connected, and the second water heater has a hot water supply position that communicates with the inside of the vacuum container but not an external hot water receiving side, and a hot water receiving position that communicates with the inside of the vacuum container but does not communicate with the external hot water receiving side. It has a hot water supply container with an on-off valve type that rotates between two positions: a hot water receiving position that communicates with the hot water side but does not communicate with the inside of the vacuum container, and an injection port is provided below the hot water supply container. are doing.

[Operation] According to the casting method or casting apparatus of the present invention having the above configuration, after receiving a certain amount of molten metal in the hot water supply container of the second water heater, by rotating the container to the hot water supply position, The molten metal is injected into the vacuum container from the injection port below the molten metal while being isolated from the outside air. In other words, while the hot water supply container receiving molten metal is in the hot water supply position and the molten metal is being injected from the injection port into the vacuum container, the closed space created by the hot water supply container and the vacuum container is completely cut off from the outside air. This creates a situation in which the gas in the molten metal is sufficiently removed during the time required for hot water supply, if it takes a long time. Moreover, while the molten metal is injected little by little from the injection port,
Since the molten metal falls into the vacuum container, sufficient contact between the molten metal and the vacuum area is achieved, and gas components are effectively extracted from the molten metal. In addition, while the hot water supply container located on the lower side of the vacuum container is in the hot water supply position and molten metal is being supplied from the hot water supply port into the sleeve, the closed space created by the hot water supply container and the sleeve is not connected to the vacuum container. Since a shut-off situation is created, the vacuum state once achieved can be maintained with almost no loss, and inside the vacuum vessel, the molten metal that is then fed to the sleeve is degassed. This means that each task can be performed continuously.

[Example] Hereinafter, the casting method of the present invention will be explained based on the drawings together with an example of the casting apparatus.

As shown in FIG. 6, the casting apparatus in this embodiment is a vacuum casting apparatus. In the same figure, 1, 2
has both molds, one being a movable mold 2 and the other being a fixed mold 1, and when both molds are closed, a cavity 3 is formed.

A sleeve 4 passes through the fixed mold 1, one end of the sleeve 4 communicates with the cavity 3 through a narrow passage gate 5, and a hot water supply port 6 is opened at the other end of the sleeve 4. A plunger tip 7 is slidably housed in the sleeve 4.

Reference numeral 8 denotes a vacuum outlet provided on the sleeve 4 side, and 8' indicates a vacuum outlet provided in the movable mold 2 so as to communicate with the cavity 3. Only one of these two extraction ports is required, and whether it is located on the sleeve 4 side or the cavity 3 side, the length of evacuation time is almost the same.

A water heater 9 is integrally connected to a hot water supply port 6 opened at one end of the sleeve 4. The water heater 9 is composed of a casing 10 and a hot water supply container 11 of an on-off valve type that slides and rotates along the inner wall of the casing 10. This hot water supply container 11 has a plurality of valve plates 11a (four in the embodiment) extending radially from a rotating shaft 13 at the center thereof.
The hot water supply port 6 is connected to outside air (atmosphere).
It rotates between two positions: a hot water supply position that does not communicate with the outside air, and a hot water receiving position that communicates with the outside air but does not communicate with the hot water supply port 6. These valve plates 11a constitute two containers 11 above and below, one communicating with the hot water inlet 12 and the other communicating with the hot water inlet 6, as shown in the figure.
That is, the two containers 11 alternately rotate between the hot water receiving position and the hot water supplying position.

A vacuum container 14 is integrally connected to the water heater 9, and another water heater (referred to as a second water heater) 15 is integrally connected to the vacuum container 14.

This second water heater 15 may have the same configuration as the water heater 9, but instead of the hot water supply port 6 that communicates with the inside of the sleeve 4 when the hot water supply container 11 of the water heater 9 is in the hot water supply position, Water supply container 1 of water heater 15
When molten metal 6 is in the hot water supply position, the opening communicating with the inside of the vacuum container 14 serves as an injection port 17 through which molten metal is injected.
In the figure, reference numeral 16a is a valve plate, 18 is a second inlet, 19 is a vacuum passage for evacuating the inside of the vacuum container 14, and 20 is a rotating shaft.

The second water heater 15 is used to supply hot water to the vacuum container 14;
From the injection port 17 communicating with the inside of the container 14, the molten metal naturally spreads and is injected into the container 14, and as is well known,
The injected molten metal is in a diffused state in the vacuum area and contacts with a large contact area, and the air in the molten metal is sucked in the vacuum area, so the vacuum container 1
After being discharged from the molten metal in 4, the vacuum passage 19
is discharged from.

In this case, the hot water supply container 16 located above the second water heater 15, that is, at the hot water receiving position, is attached to the casing 15.
If the hot water inlet 18 is kept in sliding contact with the inner wall of the vacuum container 18 so that it does not communicate with the atmosphere, air will not enter the vacuum container 14 even when the hot water supply container 16 rotates.

In the above example, the case of vacuum casting was explained, but even when casting is performed with the cavity 3 open to the atmosphere, the gas in the molten metal is extracted in advance, so a product with fewer porosity can be produced. Therefore, it is as effective as vacuum casting.

[Effects of the Invention] As is clear from the above explanation, the casting method or casting apparatus of the present invention has the following effects.

Before injecting molten metal into the sleeve from the hot water supply port,
A certain amount of molten metal is injected into a previously evacuated container, isolated from the outside air and the inside of the sleeve, and degassed while falling, so that the gas in the molten metal can be efficiently and reliably removed. In addition, when injecting molten metal into the vacuum container and injecting molten metal from the vacuum container into the sleeve, the process is completely isolated from the outside air, so excess air does not enter and the evacuation time is reduced. It can be shortened and a high quality product without blowholes can be obtained.

[Brief explanation of drawings]

Each of the figures from FIG. 1 to FIG. 4 is a cross-sectional view sequentially showing the conventional general vacuum casting process, FIG. 5 is a cross-sectional view showing another conventional process, and FIG. It is a sectional view showing an example. 1...Fixed type, 2...Movable type, 3...Cavity, 4...Sleeve, 5...Gate, 6...Hot water inlet, 7...Plunger tip, 8, 8'...For vacuuming Outlet port, 9... water heater, 10... casing, 11... hot water supply container, 12... hot water inlet, 14... vacuum container, 15... second water heater,
16...Second hot water supply container, 17...Second hot water supply port, 18...Second hot water receiving port, 19...Vacuum path.

Claims (1)

[Claims] 1. After injecting molten metal into the sleeve from a hot water supply port provided at one end of the sleeve, a plunger tip housed in the sleeve is advanced to feed the molten metal into the cavity, and the molten metal is poured into the cavity. In a casting method in which molten metal is solidified and cast, a certain amount of molten metal is injected into a pre-vacuumed container, isolated from the outside air and the inside of the sleeve, before injecting the molten metal into the sleeve from the inlet. A method for evacuation of a vacuum casting method, characterized in that after degassing while dropping, the molten metal in the container is opened and the molten metal in the container is injected into the sleeve. 2 Consists of a sleeve with a hot water supply port on one end and a plunger tip slidably housed within this sleeve, and is inserted into the cavity formed between the two molds from the other end of the sleeve through a gate. In a vacuum casting apparatus configured to feed molten metal, a water heater is connected to the hot water supply port, and the water heater has a hot water supply position that communicates with the hot water supply port but does not communicate with the inside of the vacuum container, and a water supply position that communicates with the hot water supply port but does not communicate with the inside of the vacuum container. 2. A hot water receiving position that communicates with the interior but does not communicate with the hot water supply port.
The water heater has a hot water supply container with an on-off valve that rotates between two positions, and a vacuum container with a vacuum passage is connected to the water heater. A second water heater that injects water into the water is connected in series, and this second
The water heater has two hot water supply positions, one that communicates with the inside of the vacuum container but not the external hot water receiving side, and the other that communicates with the hot water receiving side but not the inside of the vacuum container. 1. A casting device comprising a hot water supply container of an on-off valve type that rotates between two positions, and an injection port provided below the hot water supply container.