Patent ID: 7191519
Filing Date: 2007-03-20
Classification: B22C,B22D,B23P,F04D,F05D,Y10T

Abstract:
1. A method for casting a vaned diffuser ( 101 ) of a type used in a turbocharger for receiving high velocity air from a compressor wheel and supplying compressed air to an internal combustion engine, said vaned diffuser consisting mainly of a non-ferrous metal or alloy having a melting point of less than about 700° C., and said diffuser comprising an upper surface ( 105 ) and a plurality of vanes ( 113 ) radially disposed on said upper surface, the method comprising: (a) providing a male metallic template ( 201 ) comprising at least the upper surface of said diffuser ( 105 ) and further comprising a central hub ( 205 ) having an axis ( 207 ) approximately perpendicular to said upper surface; (b) casting a female plaster mold corresponding to said male metallic template by contacting said template with a plaster slurry within a suitable frame and permitting said slurry to harden; (c) separating the female plaster mold from the male metallic template by pulling along said axis ( 303 ); (d) filling said female plaster mold with a molten non-ferrous metal or alloy having a melting point of less than about 700° C.; (e) cooling said mold to form a raw vaned diffuser casting ( 4 O 7 ); (f) separating the raw vaned diffuser casting from the female plaster mold by pulling along said axis ( 403 ); and (g) finish machining the raw vaned diffuser casting ( 407 ) to form the vaned diffuser ( 101 ).