| 摘要 |
A mold for vacuum forming plastic sheet and the like and a method of making the mold. A relatively thin mold shell provides a forming surface through which small apertures open to exhaust air to vacuum form a heat-softened plastic sheet. Small manifold conduits behind the forming surface connect the apertures to a source of vacuum. The mold area subtended by the manifold conduits is substantially less than the area of the entire forming surface, thereby substantially limiting the force exerted upon the forming surface by the pressure differential created during vacuum forming of a plastic sheet. The mold is preferably made by electroforming a metallic shell on a pattern, and is apertured in a desired pattern. Filaments are advantageously used to form the apertures during electroforming. A low melting point material is applied to the back of the shell in a manifold pattern to connect the apertures and a metallic layer is electroformed to the back of the shell. The material forming the manifold pattern is then melted and removed.
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