Process for the production of precision castings by the gypsum-mold process
AssigneeGiulini Chemie GmbH
InventorsFritz Faessle, Siegmund Stadler
Life of this patent
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Abstract
Process for the production of casting parts with well-defined reproduction of detail and a great accuracy of measurement using the gypsum-form process. The pattern to be copied is equipped with a drainage apparatus, having at least one channel extending outside the molding box, and the molding material is poured into the mold and solidified. After the pattern is removed from the solidified mold by the introduction of compressed gas, the water of the solidified material is removed from, and after drying the mold is connected to a vacuum line and evacuated. The molten mass is then poured into the mold while the vacuum is maintained and solidified.
Claims14
A process for production of a precision casting, by which a porous foundry mold is produced from a pattern in a molding box out of a castable molding material, containing calcium sulfate hemihydrate as the bonding material, without calcination, comprising
- (a) coating the pattern to be copied with a mold release agent and providing the molding box pattern with a drainage having at least one duct which extends outside the molding box;
- (b) pouring the molding material into the molding box and around a portion of the drainage which is within the molding box, and solidifying the molding material in the molding box to form a solidified mold having a mold cavity;
- (c) removing the water from the solidified mold by introducing compressed gas into the drainage, whereby the pattern is removed from the solidified mold, removing the pattern from the molding box, then drying the solidified mold;
- (d) connecting the dried mold to a vacuum line and evacuating the dried mold;
- and
- (e) pouring the molten metal mass into the mold cavity while the vacuum is maintained and solidifying the molten metal.
Dependencies are inferred from the claim text.