Lester G Striker

US Patent:

6453979, Sep 24, 2002

Filed:

Nov 16, 1999

Appl. No.:

09/441259

Inventors:

Mark L. Soderstrom - Fruitport MI
Dale A. Grumm - New Era MI
Lester G. Striker - Whitehall MI

Assignee:

Howmet Research Corporation - Whitehall MI

International Classification:

B22D 1800

US Classification:

164133, 164119, 164134, 164284, 164337

Abstract:

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.

US Patent:

60191589, Feb 1, 2000

Filed:

May 14, 1998

Appl. No.:

9/253982

Inventors:

Mark L. Soderstrom - Fruitport MI
Dale A. Grumm - Zeeland MI
Lester G. Striker - Whitehall MI

Assignee:

Howmet Research Corporation - Whitehall MI

International Classification:

B22D 1800
B22D 2300
B22D 4500

US Classification:

164133

Abstract:

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.