Patent ID: 6635197
Filing Date: 2003-10-21
Classification: C06B,F42B,Y10S

Abstract:
A method of forming a cast article from a casting material that contracts as it solidifies, the method comprising:providing a mold with an opening: providing a supply of molten casting material; placing a funnel in working engagement with said opening in said mold, said funnel having an inner funnel surface for guiding said molten casting material into said mold; providing a funnel insulator having a reservoir in thermal contact with said inner funnel surface; wherein said funnel and said funnel insulator are separable pieces, wherein said funnel insulator includes a funnel-shaped surface in thermal contact with said reservoir, said funnel-shaped surface tapering from a relatively wide upper opening at a relatively narrow lower opening, wherein said funnel includes an outer funnel surface that has a slope that is steeper than a slope of said funnel-shaped surface of said funnel insulator such that there is some play between said funnel and said funnel insulator when said funnel is placed in nested engagement with said funnel-shaped surface of said funnel insulator such that said funnel can rock laterally within said funnel-shaped surface; placing said funnel in nested engagement with said funnel-shaped surface of said funnel insulator prior to pouring said molten material into said mold; providing a portion of phase-change material within said reservoir; heating said portion of phase-change material to at least partially melt said portion of phase-change material; pouring said molten casting material into said mold until said mold is completely filled and an excess amount of molten casting material is retained within said funnel; allowing said molten casting material within said mold to cool as said phase-change material provides heat to said inner funnel surface while said heated portion of phase-change material at least partially changes from a liquid phase to a solid phase, said heat from said phase change material maintaining said excess amount of molten casting material in said funnel above a melting temperature such that said excess amount of molten casting material within said funnel can feed into said mold as said casting material in said mold solidifies and contracts; allowing said casting material within said mold to cool and harden into a cast article; and removing said funnel from aid funnel insulator by breaking said funnel away from said cast article after allowing said explosive material within said projectile shell to cool and harden, said play between said funnel and said funnel-shaped surface aiding the process of breaking said funnel away from said cast article.