Method of making a unitary pattern assembly
AssigneeUnited Technologies Corporation
InventorEdward George Day
Life of this patent
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Abstract
This invention involves a method of making a unitary pattern assembly which is useful in forming investment shell molds for the conventional and directional solidification of molten metals and alloys. It comprises providing a fixture having first and second pattern capturing means, providing a mold structure having a cavity, positioning the mold structure and fixture to expose the capturing means to the cavity, forming a pattern in the cavity and removing the mold structure from the pattern. A unitary pattern assembly comprising a fixture and pattern fixedly captured therein is obtained. Multiple patterns may also be captured in the fixture. The method is especially suitable for making a pattern assembly useful in the production of gas turbine engine blades by the "lost wax" process.
Claims32
A method of making a unitary pattern assembly useful in forming investment shell molds for the conventional and directional solidification of molten metals and alloys comprising the steps of:
- a. providing a fixture, said fixture having first and second pattern capturing means rigidly spaced in open opposed relationship a predetermined distance from one another, the fixture being removable after investment molding and before casting and solidification;
- b. providing a mold structure having a cavity therein;
- c. positioning the mold structure and the fixture to expose said capturing means to the cavity;
- d. forming a pattern in the cavity, said pattern being fixedly captured at each end by said capturing means;
- and
- e. removing the mold structure from the pattern, said pattern remaining fixedly captured by said capturing means in the fixture.
A method of making a unitary pattern assembly useful in forming investment shell molds for the conventional and directional solidification of molten metals and alloys comprising the steps of:
- a. providing a fixture, said fixture comprising a yoke, having a first pattern capturing means, rigidly engaged to a second pattern capturing means, whereby said capturing means are rigidly spaced in open opposed relationship a predetermined distance from one another, the fixture being removable after investment molding and before casting and solidification;
- b. providing a mold structure having a cavity therein;
- c. positioning the mold structure and the fixture to expose said capturing means to the cavity;
- d. forming a pattern in the cavity, said pattern being fixedly captured at each end by said capturing means;
- and
- e. removing the mold structure from the pattern, said pattern remaining fixedly captured by said capturing means.
A method of making a unitary pattern assembly useful in forming an investment shell mold having an integral base, for the directional solidification of molten metals and alloys comprising the steps of:
- a. providing a fixture, said fixture having first and second pattern capturing means rigidly spaced in open opposed relationship a predetermined distance from one another, the fixture being removable after investment molding and before casting and solidification;
- b. providing a mold structure, said structure having a cavity comprising a pattern section and base section;
- c. positioning the mold structure and the fixture to expose said first capturing means to the pattern section and said second capturing means to the base section of the cavity;
- d. forming a pattern having a base integral therewith in the cavity, said pattern being fixedly captured at its end by said first capturing means and said base being fixedly captured by said second capturing means;
- and
- e. removing the mold structure from the pattern and integral base, said pattern and integral base remaining fixedly captured by said capturing means in the fixture.
A method of making a unitary pattern assembly useful in forming multiple, individual investment shell molds for the conventional and directional solidification of molten metals and alloys comprising the steps of:
- a. providing a fixture, said fixture having a plurality of first pattern capturing means rigidly spaced a predetermined distance from second pattern capturing means, each first pattern capturing means being associated with a single pattern to be formed;
- b. providing a mold structure having a cavity therein;
- c. positioning the mold structure and the fixture to expose one first pattern capturing means and second pattern capturing means to the cavity;
- d. forming a pattern in the cavity, said pattern being fixedly captured at each end by said capturing means;
- e. removing the mold structure from the pattern, said pattern remaining fixedly captured by said capturing means in the fixture;
- and
- f. repeating steps c through e until the desired number of patterns is formed and fixedly captured.
A method of making a unitary pattern assembly useful in forming a cluster of multiple investment shell molds for the conventional and directional solidification of molten metals and alloys comprising the steps of:
- a. providing a fixture, said fixture having a first and second pattern capturing means rigidly spaced in open opposed relationship a predetermined distance from one another, the fixture being removable after investment molding and before casting and solidification;
- b. providing a mold structure, said structure having a cavity in the shape of a pattern cluster;
- c. positioning the mold structure and the fixture to expose said capturing means to the cavity;
- d. forming the pattern cluster in the cavity, said cluster being fixedly captured at each end by said capturing means;
- and
- e. removing the mold structure from the pattern cluster, said cluster remaining fixedly captured by said capturing means in the fixture.
A method of making a unitary pattern assembly useful in forming a cluster of multiple investment shell molds for the conventional and directional solidification of molten metals and alloys comprising the steps of:
- a. providing a fixture, said fixture having first and second pattern capturing means rigidly spaced a predetermined distance from one another;
- b. providing a mold structure, said structure having a cavity in the shape of a partial pattern cluster;
- c. positioning the mold structure and the fixture to expose said capturing means to the cavity;
- d. forming the partial pattern cluster in the cavity, said partial cluster being fixedly captured at each end by said capturing means;
- e. removing the mold structure from the partial pattern cluster, said partial cluster remaining fixedly captured by said capturing means;
- and
- f. repeating steps c through e until a complete pattern cluster is formed and fixedly captured.
In a method of investment casting wherein a shell is formed on a pattern, the improvement which comprises:
- a. making a unitary pattern assembly comprising the steps of:
- 1. providing a fixture, said fixture having first and second pattern capturing means rigidly spaced a predetermined distance from one another;
- 2. providing a mold structure having a cavity therein;
- 3. positioning the mold structure and the fixture to expose said capturing means to the cavity;
- 4. forming a pattern in the cavity, said pattern being fixedly captured at each end by said capturing means;
- 5. removing the mold structure from the pattern, said pattern remaining fixedly captured by said capturing means in the fixture;
- b. forming a shell on the assembly;
- c. separating the shelled pattern and shelled fixture;
- and
- d. cleaning the fixture to remove the shell thereon and to prepare the fixture for reuse in steps a through c.
Dependencies are inferred from the claim text.