Dipping mandrel with a gap
A mandrel for molding polymer valve leaflets for heart valve prostheses is disclosed, including a body portion including an outer surface with ridges and contoured surfaces corresponding to the leaflets, the upper edge of the contoured surfaces corresponding to the free upper edge of the leaflets, and the mandrel including a mandrel extension above the body portion, and a gap extending around the mandrel between the upper edge of the contoured surface and the mandrel extension. A process for producing these polymer valve leaflets is also disclosed by dip coating with this mandrel and removing the polymer film created at the gap, preferably by applying suction or blowing thereto.
1. A mandrel for the molding of at least one polymer valve leaflet for a prosthesis, said mandrel comprising a body portion including an outer surface having a plurality of ridges, and at least one contoured surface between said plurality of ridges, whereby said at least one contoured surface corresponds to at least one leaflet for said prosthesis, said at least one contoured surface including an upper edge portion corresponding to the upper free edge of said at least one leaflet, said mandrel further comprising a mandrel extension portion disposed above said body portion, and an intermediate circumferential gap extending around said mandrel between said upper edge portion of said at least three contoured surfaces and said mandrel extension portion.
2. The mandrel of claim 1 for molding at least three polymer leaflets for a prosthesis, wherein said body portion includes an outer surface having at least three ridges and at least three contoured surfaces between said at least three ridges corresponding to at least three leaflets for said prosthesis.
3. The mandrel of claim 1 wherein said body portion comprises a substantially cylindrical body portion.
4. The mandrel of claim 1 wherein said circumferential gap includes a gap having a depth of between about 1 and 5 mm.
5. The mandrel of claim 4 wherein said circumferential gap has a depth of between about 1 and 2 mm.
6. The mandrel of claim 1 wherein said gap has a width between about 0.5 and 5 mm.
7. The mandrel of claim 6 wherein said gap has a width of about 1 mm.