| 摘要 |
The present invention relates to a casting procedure for obtaining parts provided with inside cavities or holes, wherein said holes and/or cavities are obtained by laying into a mould or chill, intended to receive the molten metal, one or more cores made of sand or other material, and wherein a main core is used, realised into a special core box, along one or more secondary cores intended to be associated to said main core, comprising the following steps: coating at least one secondary core, only in the zones and by the pattern thickness with a layer of material intended to dissolve in contact with the molten metal; inserting the pre-coated secondary cores into the main core box yet to be moulded; moulding the main core box; and inserting the monolithic group obtained at the previous step, consisting of the main core, of the secondary cores and of the coating material that keeps them firmly connected, into the mould or chill intended to receive the molten metal. The cores to be coated can also be formed by hollow inserts ( 23 ) made of a heat resistant material, filled with sand polymerised resin, wherein the cavity represents the core pattern.
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