Patent ID: 8591787

Claim:
A method of creating a fugitive foam pattern used to make a shell mold for an investment casting operation, the method comprising: mixing a polyol component and an isocyanate component to form a liquid mixture; adding at least one additive to the mixture of the polyol component and the isocyanate component; placing a temporary core having a shape corresponding to a desired feature of a resulting foam pattern in a cavity of a mold; inserting the mixture into the cavity of the mold such that the mixture flows into the cavity and surrounds a portion of the temporary core; waiting for a predetermined time sufficient for a reaction from the mixture to form a thermoset rigid foam pattern structure within the mold corresponding to the shape of the cavity, wherein the foam pattern structure encloses around a portion of the temporary core-such that: the foam pattern structure formed from the mixture includes a continuous, unbroken skin that prevents a slurry from penetrating the foam pattern surface when forming a shell mold using the foam pattern structure; and the formulation and density of the foam pattern structure is configured to be thermally collapsible such that the shell mold does not crack during the removal of the foam pattern structure through a burn out process; removing the foam pattern structure from the mold; and removing the temporary core from the foam pattern structure independent of chemical leaching such that the resulting foam pattern structure has the desired feature.