JPS623850A - Molding method for consumable casting mold - Google Patents

Abstract

PURPOSE:To obtain a consumable casting mold which obviates the generation of gas during casting by using a consumable pattern coated with a heat resistant material to fashion a casting mold and consuming the pattern in the casting mold heated from the periphery thereby forming the cavity coated with the coating layer. CONSTITUTION:The surface of the pattern 1 formed of the material to be consumed by heating is coated with the ceramic coating layer 2 and thereafter the pattern is contained into a molding flask 3 and is embedded in molding sand, by which the casting mold 5 is formed. The surface of the mold 5 is heated by a heating means 6 such as burner to consumer the pattern 1 and the cavity 5b whose inside surface is coated with the coating layer 2 is formed in the mold 5. A sprue 5a is similarly formed to a sprue pattern 4 as well. The consumable casting mold which does not generate the harmful gas during casting is thus molded.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a method of manufacturing a fugitive mold, which uses a pattern that disappears due to heat to form a mold.

2. Description of the Related Art A method of forming a mold used in conventional casting using a model that disappears due to heat is already known.

In addition, the model used for the above molding is JP-A-55-77
'? 5'? The invention has already been filed and is publicly known in Japanese Patent Application Laid-Open No. 55-88499.

Problems to be Solved by the Invention However, in conventional vanishing molds, molten metal is poured into the mold and the model inside the mold disappears due to the heat of the molten metal.

For this reason, when a model made of polystyrene or the like disappears, a large amount of gas is generated, and this is removed by suction using a suction device, but the gas that cannot be suctioned out remains as bubbles inside the casting, causing cavities and the like. This was the cause of the occurrence.

This invention was made for the purpose of improving the above-mentioned problems.

Means and effects for solving problems Forming a model from a material that disappears when heated,
After forming a coating layer on the surface of this model using a heat-resistant material, it is buried in molding sand to form a mold. To form a cavity covered with a coating layer, the model in the mold is eliminated before casting,
A method for creating a vanishing mold that prevents gas generation during casting.

Embodiment An embodiment of the present invention will be described in detail with reference to the drawings. In the figure, 1 is a model formed by injection molding of a resin that disappears when heated, such as polystyrene, and by combining two of this model I, for example, a model identical to the product shown in Figure 2 is produced. 1. Of course, a single model may be used depending on the product.

Next, a ceramic coating layer 2 of a constant thickness is formed over the entire circumference by coating or spraying ceramic on the surface of the model 10.

Next, the model 1 with the ceramic coating layer 2 formed thereon is housed in the flask 3, and the flask 3 is filled with molding sand to form the mold 5. At this time, the sprue model 4 coated with ceramic is also embedded at the same time.

Next, the surface of the mold 50 obtained is heated with a heating means 6 such as a burner to eliminate the models 1 and 4 inside the mold 5.
The gas generated by the disappearance of the molds 1 and 4 is released into the atmosphere from the sprue 5a, and a cavity 5b whose inner surface is covered with the ceramic coating layer 2 that does not disappear even when heated is formed in the mold 5. Ru.

Furthermore, the mold can be used for casting by pouring the metal into the cavity 5b in the dissipating mold 5 obtained by the above-mentioned molding method through the sprue 5a.

Although the coating layer 2 is made of ceramic in the above embodiment, it may be made of a heat-resistant material that does not disappear even when heated and that can be coated or sprayed.

Effects of the Invention As detailed above, this invention eliminates the model in the mold before casting, so no gas is generated during casting, and this eliminates the need for a costly gas suction device. In addition to reducing equipment costs, it is also possible to prevent gas from entering the casting and causing defects. In addition, since the inner surface of the cavity formed after the model disappears is covered with a coating layer such as ceramic, there is no need for binder or sand removal after casting, which saves labor during molding and casting. At the same time, it becomes possible to improve the dimensional accuracy of the product.

[Brief explanation of the drawing]

1 to 5 are process diagrams showing one embodiment of the present invention. 1 is a model, 2 is a coating layer, 5 is a mold, and 5b is a cavity.

Claims (1)

[Claims] A model 1 is formed using a material that disappears when heated, and a coating layer 2 is formed on the surface of the model 1 using a heat-resistant material, and then buried in molding sand to form a mold 5. A method for manufacturing a vanishing mold, in which a cavity 5b whose inner surface is covered with a coating layer 2 is formed in the mold 5 by heating the surroundings to make the model 1 in the mold 5 disappear.