JP3210467B2 - Vanishing model casting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vanishing model casting method, and more particularly to a method for effectively capturing a decomposition gas or a liquid product generated from a vanishing model so that it can be efficiently replaced with metal. About.

[0002]

2. Description of the Related Art One of casting methods uses a vanishing model. A conventional vanishing model casting method will be described with reference to FIG. The disappearance model 105 is formed of a foamed resin (for example, styrene foam or PMMA), and has the same shape as a product to be cast. A runner 107 made of a foamed resin is connected to the vanishing model 105. A coating agent is applied to the outer surface of the disappearing model 105 and dried to form a coating agent layer 106. Next, the vanishing model 105 is placed in the flask 101, and the surroundings are filled with molding sand 103. Runner 107 is foundry sand 103
The inside is vertically arranged, and a sprue cup 109 is arranged at the upper end thereof.

[0003] Next, a molten metal is poured into the above-mentioned gate cup 109. The molten metal causes the runner 107 to melt and disappear, and further causes the disappearance model 106 to disappear and replace the molten metal. As a result, a product having the same shape as the vanishing model is cast.

[0004]

According to the above-mentioned conventional configuration, there are the following problems. As shown in FIG. 6, when the molten metal is poured into the vanishing model 105, the styrofoam and PMMA, which are the materials of the vanishing model 105, are thermally decomposed by the molten metal and become a decomposition gas or a liquid product to form the coating agent layer 10.
6 are diffused and trapped in the molding sand 103. However, since the molding sand 103 has a lower temperature than the temperature of the resin that is the decomposition gas or liquid product, the decomposition gas or the liquid product that has entered the molding sand 103 is rapidly cooled, solidified again, and The grain boundaries are closed (indicated by reference numeral 111 in the figure), and it becomes difficult to diffuse a decomposition gas or a liquid product exceeding a certain amount.

That is, since the foundry sand 103 is a good heat insulating material, the thickness of the sand layer heated by the molten metal to a temperature higher than the decomposition temperature of the resin is only a few millimeters outside the vanishing model 105, This is because solidified decomposed products are clogged in the grain boundaries of the sand layer, and the diffusion of the decomposed gas or the liquid product in a certain amount or more into the sand layer is excluded.

Conventionally, as a solution to these problems, a method of increasing the grain boundary volume by using a casting sand 103 having a larger grain size has been mainly used. However, there is a limit to that, and there is a limit. When the casting sand 103 having a diameter is used, the molten metal passes through the coating agent layer 106 and the casting sand 103.
This causes a defect referred to as insertion, which penetrates into the device.

The present invention has been made based on such a point, and an object of the present invention is to effectively capture a large amount of a decomposition gas or a liquid product generated from a vanishing model,
It is an object of the present invention to provide a vanishing model casting method capable of realizing quick substitution with metal and obtaining a good quality casting.

[0008]

In order to achieve the above object, a vanishing model casting method according to the present invention comprises forming a coating agent layer on the surface of a vanishing model, and disposing the vanishing model in a casting flask to form the vanishing model. In the vanishing model casting method, in which the surrounding area is filled with sand and the molten metal is poured into the vanishing model, it is adhered to the outer surface of
After applying the agent, a porous material is adhered to the adhesive to form a porous material layer.

[0009]

In the case of the present vanishing model casting method, a porous material layer is formed on the outer surface of the coating agent layer. As the method is intended to deposit on the outer surface of the mold wash layer an adhesive is applied a porous material on its outer surface. When casting is performed using this vanishing model, the vanishing model becomes a decomposition gas or a liquid product, passes through the mold wash agent layer, and when it is discharged into the molding sand, the porous material layer decomposes inside. It absorbs and captures gas or liquid products and reduces the amount of decomposed gas or liquid product that cools and solidifies in molding sand. Spread,
Quick replacement with metal can be realized.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will now be described with reference to FIGS.
An embodiment will be described. First, as shown in FIG.
Is formed on the surface of the substrate. The coating agent is a general one used in the vanishing model casting method, and is applied by a method such as drenching or spraying and dried.

Next, as shown in FIG.
The porous material layer 5 is formed on the outer surface of the substrate. As the porous material, a material in which a coal-based porous material such as pumice, volcanic ash, charcoal, activated carbon, and coke is powdered is used. As a method for forming the porous material layer 5, a vinyl acetate-based adhesive 7 diluted in water is applied to the outer surface of the coating agent layer 3,
A porous material is attached to the outer surface. The thickness of the porous material layer 5 is arbitrary, but is about several millimeters as an example. As a result, the porous material layer 5 is
Separated from the vanishing model 1 and has a multilayer structure.
You.

Next, as shown in FIG.
Is placed in a casting flask 9 and sand 11 is filled around the disappearing model 1 to complete the disappearing model casting apparatus. Then, one molten metal is poured into the disappearance model.

Then, as shown in FIG. 4, the styrofoam and PMMA, which are the materials of the vanishing model 1, are thermally decomposed by the molten metal, become decomposed gas or liquid product, pass through the mold wash agent layer 3, and the molding sand 11 Dispersed and discharged inside. At this time, the decomposition gas or the liquid product reaches the porous material layer 5 after passing through the coating agent layer 3. The porous material layer 5 absorbs and captures these decomposition gases or liquid products 13 inside the porous material itself. As a result, the amount of decomposition gas or liquid product diffused into the molding sand 11 decreases, and the molding sand 1
(1) Since the amount of decomposition gas or liquid product that is cooled and solidified in 1 is also reduced, the diffusion of decomposition gas or liquid product into molding sand becomes smooth, and rapid replacement with metal can be realized. It is.

According to this embodiment, the following effects can be obtained. First, since the porous material layer 5 is formed on the outer surface of the coating material layer 3, a decomposition gas or a liquid product generated at the time of pouring can be absorbed and captured inside the porous material layer 5 itself. As a result, the amount of decomposition gas or liquid product that diffuses into the casting sand 11 and is cooled and solidified can be reduced, so that smooth replacement with metal can be achieved and a high quality casting can be obtained. be able to.

Further, since the porous material layer 5 is separated from the disappearance model 1 by the coating agent layer 3, the molten metal is directly transferred to the porous material layer 5.
, And the particle size of the porous material layer 5 can be reduced, so that there is no risk of insertion and an excellent product casting with a clean casting surface can be obtained.

[0017]

As described in detail above, according to the vanishing model casting method of the present invention, a large amount of decomposed gas or liquid product generated from the vanishing model can be effectively captured and replaced with the metal promptly. A good quality casting can be obtained. In addition, the porous material layer is a model that disappears due to the coating agent layer.
Separated so that molten metal penetrates directly into porous material layer
And the particle size of the porous material layer can be reduced.
And there is no risk of insertion and the casting surface is clean and excellent
Product castings can be obtained .

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, and is a cross-sectional view showing a state in which a coating agent layer is formed.

FIG. 2 is a cross-sectional view illustrating a state in which a porous material layer is formed in the first embodiment of the present invention.

FIG. 3 is a view showing the first embodiment of the present invention, and is a cross-sectional view showing the vanishing model casting apparatus.

FIG. 4 is a view showing the first embodiment of the present invention, and is a cross-sectional view showing a state in which a decomposition gas or a liquid product diffuses into molding sand.

FIG. 5 is a sectional view showing a vanishing model casting apparatus in a view showing a conventional example.

FIG. 6 is a cross-sectional view showing a conventional example in which a decomposition gas or a liquid product is diffused into molding sand.

[Explanation of symbols]

 1 Disappearance model 3 Coating agent layer 5 Porous material layer 7 Adhesive 9 Casting frame 11 Foundry sand

Claims (1)

(57) [Claims] 1. A vanishing model casting method in which a mold wash agent layer is formed on the surface of a vanishing model, the vanishing model is placed in a casting frame, sand is filled around the vanishing model, and a molten metal is poured into the vanishing model. In the above , after applying an adhesive to the outer surface of the coating agent layer ,
A vanishing model casting method, comprising forming a porous material layer by attaching a porous material to the adhesive .