Howmet Research Corporation

Lester G Striker

Mark L Soderstrom

Dale A Grumm

Method and apparatus for investment casting wherein a ceramic investment mold is disposed in a chamber and communicates with a melt reservoir connected to the mold and having a reservoir volume for holding enough melt to fill the mold. The melt pour cup reservoir is communicated to the mold via an inverted loop feed gate so that the melt is fed from a lower region of the reservoir through the inverted loop feed gate to the mold upon gas pressurization of the melt in the reservoir. The loop feed gate is configured to have a loop region above the melt level in the reservoir so as to prevent melt flow from the reservoir to the more mold cavities in the absence of pressurization. While residing in the reservoir, oxides and other inclusion-forming particles in the melt can float to the upper surface of the melt, whereby the melt fed from the lower region of the reservoir to the mold via the inverted loop melt feed gate includes reduced amount of inclusion-forming particles.

Investment casting using melt reservoir loop

A ceramic investment mold is disposed in a casting chamber and communicates with a pour cup melt reservoir connected to the mold and having a reservoir volume for holding enough melt to fill the mold. The melt pour cup reservoir is communicated to the mold via an inverted loop feed gate so that the melt is fed from a lower region of the reservoir through the inverted loop feed gate to the mold upon gas pressurization of the reservoir. The loop feed gate is configured to have a loop region above the melt level in the reservoir so as to prevent melt flow from the reservoir to the more mold cavities in the absence of reservoir pressurization. While residing in the pour cup reservoir, oxides and other inclusion-forming particles in the melt can float to the upper surface of the melt, whereby the melt fed from the lower region of the reservoir to the mold via the inverted loop melt feed gate includes reduced amount of inclusion-forming particles. After the melt is introduced into the pour cup, a pressure cap can be positioned in sealing engagement with the pour cup to provide selective or local gas pressure on the melt in the pour cup reservoir to force the melt in the reservoir through the inverted loop feed gate into the mold cavities to fill same.

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Whitehall, MI, United States of America

Lester G Striker