| 摘要 |
<p>A vaporizable refractory coated pattern assembly (10) is formed having a sprue (14) connected to a plurality of thin wallpatterns of articles (16) to be cast. The pattern assembly is supported in a refractory particulate media (30) in an open bottom container (40) that is evacuated to subambient pressure and rotated in a manner to distribute particulates (48) to regions (RR) of the refractory coated patterns not yet directly contacted by particulates. The pattern assembly is comprised of relatively dense foam plastic pattern material that imparts increased strength to the thin wall patterns. The sprue includes a vent passage (12a) that communicates to a particulate media to vent pattern decomposition vapors thereto in a manner that enables faster replacement of the pattern assembly in the media, despite the use of the relatively dense pattern material.</p> |
