JPH05138290A - Production of expendable pattern casting mold and casting method - Google Patents

Abstract

PURPOSE:To prevent the blow-off of a molten metal and improve the safety by mounting a porous filter having open cells to the expendable pattern casting mold, thereby suppressing the release of black smokes at the time of casting. CONSTITUTION:A proper amt. of furan sand is charged into a molding flask 4 and thereafter, the expendable pattern 1 and a riser 3 are inserted into the molding flask 4. A sprue sleeve 2 is then mounted to the flask. The casting mold is produced by charging the furan sand 5 into the flask. A core print for setting the porous filter 6 having the open cells is provided in the upper part of the riser 3. The porous body of ceramics having a three-dimensional network structure is used as the heat resistant filter for the porous filter 6 having the open cells.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method and a casting method of a vanishing model mold for producing castings using a vanishing model.

[0002]

2. Description of the Related Art A method of manufacturing a casting using a fusible model is more difficult than a general cavity-type casting method because it uses a model of fusible foam beads for the model. There is no need to set or cover the mold. Therefore, cast products manufactured using the fugitive model have no casting and the product finish is easy, or the model cost is cheaper than the conventional wooden mold, resin mold, and mold. Due to such advantages, it is being widely used in industrial machine parts, automobile parts, etc., including stamping dies for automobiles. However, this method uses an extinguishing material for the model,
There is a drawback that carbides (generally called residues) remain near the upper surface of the cast product. FIG. 2 shows a method using a conventional open type feeder, FIG. 3 shows a conventional blind feeder method, and FIG. 4 shows a vacuum casting method. In the conventional open type feeder method shown in FIG. 2,
An appropriate amount of casting sand 5 (sand mixed with a low binder or non-caking sand) is put into the flask 4. After inserting the model 1 and the open-type riser 3 made of vanishing material and attaching the sprue sleeve 2, the remaining casting sand 5 is put into the flask 4 to manufacture a mold. After the casting mold is manufactured, the molten metal injection cup 7 is attached above the sprue sleeve 2, and a molten metal (not shown) is injected and cast from the molten metal injection cup 7 to manufacture a casting. The conventional method of adopting a blind feeder shown in FIG. 3 is the same as the method of adopting an open type feeder described above. In the conventional vacuum casting method shown in FIG. 4, an appropriate amount of non-caking sand 5 is put into the flask 4a with a vacuum function. After the vanishing model 1 and the blind feeder 3a are inserted into the casting frame and the sprue sleeve 2 is attached, the remaining non-caking sand 5 is charged and vibration filling is performed to manufacture a mold. After making the mold, the molten metal injection cup 7 is attached above the sprue sleeve 2, and the molten metal is injected from the molten metal injection cup 7 while suctioning and depressurizing the inside of the mold through the suction pipe 11, the wire net 9 and the jacket portion 10 with a depressurizing device (not shown). Pouring and manufacturing castings.

[0003]

The polystyrene used for the vanishing model has a composition of carbon 92% and hydrogen 8%, and has a composition of about 80%.
It has the property of softening at ℃, decomposing into monomers at 420 to 480 ℃, and producing low molecular hydrocarbon gas and styrene monoer gas at higher temperatures. Therefore, when a high temperature molten metal is poured into the mold, soot of graphite crystals is generated. This soot is not only the quality of the casting, but also a serious problem that deteriorates the working environment. INDUSTRIAL APPLICABILITY The present invention, when casting with a disappearance model mold, eliminates residues (carbides) generated near the casting surface or the carburization phenomenon, the deterioration of the environment in the factory, and the disappearance of dangerous work. It is intended to provide a method for manufacturing a model mold and a method for casting.

[0004]

Means for Solving the Problems The manufacturing method and casting method of the disappearance model mold of the present invention have taken the following means. A porous body filter having continuous pores is provided on a feeder provided to prevent shrinkage cavities of a casting or on the upper part of a gas lifter.

[0005]

In the present invention, for example, the low molecular hydrocarbon gas and styrene monomer gas generated when the molten metal is cast into the casting mold are the feeder and the gas pump provided with the porous body filter having continuous pores. However, due to the air blocking effect of the porous filter with continuous pores,
The generation of carbides is suppressed, and black smoke containing carbides is captured and adsorbed. Further, when the molten metal is cast, the phenomenon of blowing out the molten metal due to the rise of the gas pressure in the mold is completely eliminated. In addition, various functions such as reduction of carbide residue generated near the surface of the casting and reduction of seizure which is one of casting defects are improved.

[0006]

Embodiment An embodiment of the present invention will be described with reference to FIG.

After an appropriate amount of furan sand (0.8% furan resin, 35% hardener against resin) was placed in the flask 4, the fusible model 1 and feeder 3 were inserted into the flask 4 and Attach the sleeve 2. Then, furan sand 5 is charged to produce a mold. A width ruler for setting the porous body filter 6 having continuous pores is provided above the feeder 3.

After the casting mold is manufactured, in this embodiment, as the porous body filter 6 having continuous pores, a ceramic porous body having a three-dimensional network structure (silicon carbide: apparent specific gravity 0.35) is used.
~ 0.55, porosity 80 ~ 90%, cell number 20/25 〓 mouth) was used as a heat resistant filter, and as a result of casting Fc 250 cast iron molten metal, the amount of black smoke generated was about 1/2 of that of the conventional method. It was possible to suppress to the extent of, and it was possible to prevent the molten metal from being blown out at the time of casting. Further, in the conventional method, it is common sense to apply a coating material to the surface of the fugitive model to prevent seizure. It was possible to obtain a beautiful casting with less seizure and no seizure.

As another embodiment, it is also a consideration to attach a porous filter to the gas lifter, the jacket portion, the suction pipe and the like.

[0010]

The present invention described in the claims has the following effects because a porous filter having continuous pores is attached to the disappearing model mold. It is possible to greatly suppress the emission of black smoke into the atmosphere generated when the molten metal is cast, and it is effective in improving the environment and preventing pollution. There is no blowing out of the molten metal from the riser and gas frying which are likely to occur during molten metal casting, and safety is improved. During casting of molten metal, the amount of residue or carburization that occurs near the surface of the casting due to the restriction of oxygen supply to the mold,
It can be significantly reduced. Since the gas pressure acting on the mold wall is reduced along with the suppression of the generation amount of low-molecular hydrocarbon gas, it is possible to reduce the coating man-hours and the material cost of the mold coating material to be applied to the fugitive model.

[0011]

[Brief description of drawings]

FIG. 1 is a vertical view of an embodiment of the present invention.

[Fig. 2]

[Figure 3]

FIG. 4 is a vertical cross-sectional view showing a conventional disappearing model casting method.

[Explanation of appendices] 1… Disappearance model 2 ……… Gate sleeve 3 ……… Disappearance riser model 3a ……… Disappearance blind riser model 4 ……… Casting frame 4a ……… Decompression function Attached casting frame 5 ………… Fran sand 6 ………… Porous filter (non-caking sand) 7 ……… Molten metal injection cup 8 ……… Gas frying 9 ……… Wire mesh 10 ……… Jacket 11… ...... Suction pipe

Claims (1)

[Claims] 1. A method for producing a casting using an extinguishing model, the method for producing an extinguishing model mold, comprising providing a porous body filter having continuous pores, and a casting method.