PURPOSE: To permit decompression casting of thin-walled castings of intricate shapes having thick walled parts partially by decompressing the inside of a mold through decompression holes of a chiller and teeming molten metal from above the metallic foil opposite to a pouring cup thereby melting the metallic foil.
CONSTITUTION: A decompressing device is operated to extract air from a decompressing vessel 14. By this air extraction effect, the entire part of a mold 10 is put in a decompressed state through holes 26 for decompression. At this time, the mold 10 is thoroughly hermetically sealed by the sealing jig 34 and metallic foil 36 between a chiller 24 and the same, and the part between the vessel 14 and the chiller 12 is also sealed by a sealing jig 28, therefore, the decompression is accomplished efficiently and the inside of the cavity 16 is also surely decompressed. Thence, the molten metal which is a raw material for casting is charged from above the foil 36 opposite to a pouring cup 22. As a result, the molten metal breaks the foil 36 by the effect thereof and is instantaneously filled in the cavity 16 which is held decompressed. In a thick-walled part 29, directional solidification is accomplished by the chiller 12, whereby the occurrence of shrinkage defects is obviated.
FUKUDA TOKIHARU
KURODA KUNIO
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