Mold and molding process
A method and apparatus for forming a member, such as a column. The invention comprises inner and outer molds that are spaced apart forming a cavity for receiving a viscous material for making the member. A core is inserted within the inner area of inner mold when the viscous material is initially disposed within the mold. Once the material attains a gelled state, an extraction member is inserted within the inner area. A vacuum is applied to the inner area that causes the flexible inner mold to separate from the material and conform to the extraction member allowing for removal.
1. A method of molding columns comprising the steps of:
a) molding a column between an outer mold and an inner mold, said inner mold having a flexible wall and a hollow interior;
b) inserting a rigid core piece into said hollow interior of said inner mold during a molding step, the rigid core piece being sized to prevent the inner mold from collapsing inward during the molding process;
c) removing the rigid core piece from the hollow interior of said inner mold;
d) inserting an elongated extraction member into said hollow interior of said inner mold following said molding step to extract said inner mold from the hollow part, said extraction member extending substantially the entire length of said inner mold;
e) applying a vacuum to said hollow interior of said inner mold to collapse said inner mold against said extraction member while said inner mold is extracted from said hollow part; and
f) withdrawing said extraction member and said inner mold from said molded column.
2. The method of claim 1 , further comprising tapering the hollow interior and the extraction member to ease removal of the extraction member from the hollow interior.
3. The method of claim 2 , further comprising lubricating the extraction member prior to insertion into the hollow interior.
4. The method of claim 1 , further comprising forming a bottom of the extraction member to have a larger surface area than an inner mold bottom.
5. The method of claim 1 , wherein the step of applying a vacuum within the hollow interior causing the flexible inner mold to conform to the extraction member comprises inserting a top across the inner mold, the top having a duct through which a vacuum source pulls airs from the hollow interior.
6. A method of forming a column comprising the steps of:
a) providing a mold comprising an outer mold and a flexible inner mold, the inner mold having a hollow interior;
b) inserting a core into the hollow interior, the core being sized to prevent the inner mold from collapsing inward during the molding process;
c) filling a cavity between the outer mold and the inner mold with a viscous material;
d) allowing the viscous material to attain a gelled state;
e) removing the core from the inner area;
f) inserting an extraction member into the inner area, the extraction member comprising a larger cross sectional area than the inner mold;
g) applying a vacuum within the inner area causing the flexible inner mold to conform to the extraction member; and
h) removing the extraction member and the inner mold.
7. The method of claim 1 wherein an exterior surface of the rigid core piece contacts an inner surface of the inner mold.
8. The method of claim 6 wherein an exterior surface of the core presses against an inner surface of the inner mold.