Patent ID: 7500507
Filing Date: 2009-03-10
Classification: B22C,B22D

Abstract:
1. A pouring method in a vacuum sealed process comprising the steps of: sealingly covering the surface of a pattern plate by a shielding member; placing a mold framing on the shielding member and then putting a fill that does not include any binder in the mold framing; sealingly covering an upper surface of the fill and then evacuating an inside of the mold framing to suck the shielding member to the fill to shape the shielding member; removing the pattern plate from the shielding member, thereby forming an upper mold half that has a molding surface; forming a plurality of apertures in a part of the shielding member that contacts with the molding surface of the upper mold half; forming a lower mold half in a similar way and mating the mold halves to define a molding cavity; pouring molten metal in the molding cavity; and releasing a negative pressure in the mold framing to take out an as-cast product, wherein the method further comprises the steps of: measuring a degree of pressure reduction for at least one of the upper and lower mold halves during a period between the start and end of the pouring of the molten metal in the molding cavity; and decompressing one mold half and the the molding cavity so that Pm=1-75 KPa, Pc=4.95 KPa, and Pc−Pm=3-94 Kpa, where Pm and Pc are a pressure within the one mold half and a pressure in the molding cavity, respectively.