| 摘要 |
Foundry molding material is poured or pneumatically infed into a mold frame arrangement containing at least one pattern, a molding frame and a filling frame. Subsequently, the foundry molding material is compacted by a compacting arrangement containing, for example, any one of a compressed-air surge compacting device, a combustion-force surge compacting device, a pressure compacting device, a vibrational compacting device or a combined pressure-and-vibrational compacting device. Also during such compacting operation at least the predominant portion of the foundry molding material contained in the filling frame is displaced into the molding frame. During such compacting operation a preselected expanding gas is infed into predetermined local regions of the foundry molding material while such material is being compacted. As a result, there are formed zones of reduced packing density in the foundry molding material. During the further compacting operation, but in any case at the end of such compacting operation, the zones of reduced packing density are eliminated and the packing density of such zones is at least approximately equalized with the packing density prevailing in the remaining zones of the foundry molding material.
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