JPH0313934B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for casting a casting using a fugitive pattern, which is used in the foundry industry.

Conventional technology In this type of casting method, a fugitive model made of foamed synthetic resin such as foamed polystyrene is buried in a nonflammable filler such as sand contained in a flask, and molten metal is poured into the mold through a sprue or runner. (hereinafter referred to as hot water) is injected, the model is gasified and disappears, and the space created there is entered to perform casting.

Problems to be Solved by the Invention The above conventional method has the following problems. In the case of casting using a fugitive model, sand is used as the filler, but dry sand without binder is used as the foundry sand. For this reason, the poured molten metal cools more slowly than the green mold. Also, depending on the shape of the product, there may be a portion where solidification is slow, and a hollow so-called shrinkage cavity may occur inside the portion.

In this case, in order to prevent the occurrence of such shrinkage cavities, conventionally, as shown in FIGS. 6 and 7, a riser part c is provided above the product model a via a weir b.
This allows for boiling and prevents the occurrence of shrinkage cavities. In the figure, d is a runner, e is a sprue, and f is a protective layer such as a coating mold. However, the above-mentioned feeder generally requires an amount of feeder approximately equal to the weight of the product. This is because if the amount of feeder is small, the feeder will solidify first, which will have the opposite effect.

Further, even if the boiler is heated in the usual manner, it is difficult to completely eliminate the above-mentioned shrinkage cavities.

This invention was made to solve these problems, and its purpose is to reduce the amount of feeder than the conventional method and to completely eliminate the occurrence of so-called shrinkage cavities. can,
An object of the present invention is to provide a method for casting a casting using a fugitive model.

Means for Solving the Problems The present invention is characterized in that a feeder section is integrally provided above a product model made of foamed synthetic resin via a weir, and the feeder section has a runner having a sprue. A non-flammable filler storage part is formed inside the feeder part to form a fugitive model, a protective layer such as a coating is formed on the surface of the fugitive model, and the model is This is a method for casting a casting using a fugitive model, characterized in that the mold is embedded in the filler housed in a flask, the filler is housed in the housing part, and molten metal is injected from the sprue.

Effect When the above-mentioned fugitive model is buried in a nonflammable filling housed in a flask, the filling fills the outside of the feeder part and the inside of the storage part formed inside the feeder part. Fill it. In general, fillers such as sand have low thermal conductivity and are poor thermal conductors. Therefore, the above-mentioned accommodating part is formed as a heat insulating part. For this reason, if pouring is performed,
The boiler is kept warm.

Moreover, as a result of the above-mentioned heat retention, the amount of feed water can be saved.
As mentioned above, since the feeder is kept warm, it is possible to slow down the coagulation of the feeder, increasing the effect of the feeder.

Embodiment In FIGS. 1 to 4, 1 is a product model, 2 is a weir, 3 is a feeder, 4 is a storage area for filling such as sand, 5 is a runner, 6 is a connecting part, and 7 8 is a sprue, and 8 is a protective layer for coating molds, etc. 9 indicates the evanescent model formed as described above. And the housing section 4
may be formed in the shape of a hole as shown in FIG.
Alternatively, it may be formed into a ring shape as shown in FIG. In addition, although not shown in the drawings, the housing may have a square hole shape, a square ring shape, or a plurality of hole-shaped housing portions. Preferably, they are formed symmetrically or balanced in cross section with respect to the center.

The housing portion 4 is preferably formed in the vertical direction as shown in the figure. It is filled with sand etc.
This is because it is easy to enter the filling material because it is dropped from above, and the filling material is effectively densified when vibration is applied by a vibrator (not shown) to make the filling material dense. Note that although the sprue 7 is formed integrally with the runner 5, this is just an example, and the invention is not limited to this, and the sprue 7 may be formed and attached separately. In Fig. 5, 10 is a flask, 11 is a nonflammable filler such as sand,
12 is a gas vent having a vent 13, and 14 is an ignition device. Further, 15 indicates a furnace mouth, and 16 indicates hot water, which is molten metal. 17 is a roller, 18 is a shaft support, and the cylinder, piston, etc. for moving the flask 10 are not shown. The hot water 16 sequentially reaches the feeder section 3 and the product model 1 from the runner 5, and casting is performed. During that time, the runner 5, riser 3, and product model 1 are each gasified and disappeared, and the generated gas passes through the minute gaps in the filling 11 to the vent 13.
The gas enters the evacuated gas 12, rises through the evacuated gas 12, and is ignited by an ignition device 14 at its exit to be combusted.

Note that the gas processing method described above is not limited to this, and it goes without saying that other generally known methods may be used.

In this embodiment, as a result of the above, the amount of feeder in the feeder section 3 was reduced by approximately 20%, resulting in savings. Furthermore, by using the method of this invention, it was possible to completely eliminate so-called shrinkage cavities in castings.

Effects of the Invention The present invention is configured as described above, and a fugitive model made of foamed synthetic resin is provided with a storage part for a nonflammable filler inside the feeder part, and this fugitive model is used to By casting a cast metal, the amount of feeder can be reduced to a greater extent than in the conventional method described above. Furthermore, the occurrence of so-called shrinkage cavities can be completely eliminated.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention, and is a half-sectional perspective view of a fugitive model used in the casting method of the invention, and Fig. 2 shows another embodiment of the invention, and is a view corresponding to Fig. 1. Figure 3 is an enlarged detailed view of the part in Figure 1;
FIG. 4 is an enlarged detailed view of the part shown in FIG. 2, FIG. 5 is a diagram showing the outline of the present invention, FIG. 6 is a half-sectional perspective view of a fugitive model used in the conventional homogeneous casting method, and FIG. It is the same perspective view. 1...Product model, 2...Weir, 3...Riser section, 4
...Receiving part for non-combustible filling, 5... Runway, 8...
...protective layer, 9...disappearance model.

Claims (1)

[Claims] 1. A feeder part is integrally provided above the product model made of foamed synthetic resin via a weir, a runner with a sprue is provided in the feeder part, and a non-flammable material is installed inside the feeder part. forming a fugitive model by forming a storage part for the filler, forming a protective layer such as a coating mold on the surface of the fugitive model, embedding the model in the filler housed in a flask; A method for casting a casting using a fugitive model, characterized in that a filler is accommodated in the accommodation part and molten metal is injected from the sprue.