| 摘要 |
A vacuum countergravity casting apparatus includes a vacuum chamber (34) and a gas permeable mold (14) sealingly mounted in the mouth of the chamber and comprising a gas permeable upper mold member (16) and a lower mold member (18) held in sealing engagement at a mold parting plane without glue. To this end, the upper mold member (16) includes an exterior mold surface (16b) confronted by the vacuum chamber (34) and a plurality of vacuum passages (82) extending between the exterior mold surface and a bottom parting surface (16a) thereof to expose an effective area of the lower mold member (18) to subambient pressure in the chamber sufficient to urge the lower mold member (18) into sealing engagement with the upper mold member (16) at the mold parting plane (20). The vacuum chamber (34) includes a mold-engaging stop member (80) for engaging the upper mold member (16) and limiting movement of the upper mold member (16) inwardly of the vacuum chamber (34) away from the lower mold member (18) as the latter is urged into sealing engagement therewith.
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