Abstract The production of foam material, e.g., a reticulated ceramic, metal or cermet material, is carried out by using commercially available conventional foam, such as reticulated polyurethane, having the desired pattern for the end product. This foam serves as a pattern for the mold and is embedded in mold material of plaster of paris or the like, which sets to form a solid structure in and around the plastic foam. This investment structure is then heated to volatilize and expel the plastic foam, leaving voids in the mold corresponding to the original configuration of the foam. Molten metal or other substance is then cast through the voids or openings in the mold and permitted to cool and set. The mold structure is then washed away, leaving a reticulated structure of integrally formed ligaments of metal, ceramic, cermet or other desired substance.
A method as set forth in claim 1 in which a pressure differential is created on different portions of said investment during the introduction of the molten substance therein, with said substance being introduced on the portion of greatest pressure.
Claim 2
Dependent Claim
31 words
A method as set forth in claim 2 in which said investment is subjected to a vacuum adjacent a portion thereof remote from the portion wherein the substance is being introduced.
Claim 3
Dependent Claim
27 words
A method as set forth in claim 2 in which said investment is subjected to gas pressure adjacent the portion thereof wherein the portion is being introduced.
Claim 4
Dependent Claim
23 words
A method as set forth in claim 4 in which said gas is selected from the group consisting of air and inert gases.
Claim 5
Dependent Claim
21 words
A method as set forth in claim 1 in which said investment is vibrated as the molten substance is poured therein.
Claim 6
Dependent Claim
44 words
A process in accordance with claim 1 wherein a temporary increase in the cross-sectional dimension of the ligaments of said foam is accomplished by coating said ligaments with a thin layer of a wax selected from dental wax, investment wax , or household parafin.
Claim 7
Dependent Claim
30 words
A process in accordance with claim 7 wherein the temporary increase in the cross-sectional dimension of the ligaments of said foam is accomplished by swelling said ligaments with a solvent.
Claim 8
Dependent Claim
12 words
A process in accordance with claim 8 wherein said solvent is trichorethylene.
Claim 9
Dependent Claim
15 words
A process in accordance with claim 1 wherein the insoluble molten material is molten aluminum.