摘要 |
A process and apparatus for forming a sheet material by drawing it into a die cavity (12) utilizing the flow of a viscous thermoplastic polymer medium extruded against the sheet (22) and/or extruded out of said die cavity (12) through a plurality of passageways, (14a), (14b), and (14c) and programmably varying said extrusion of said medium to cause the sheet material to be controllably stretched into the cavity and shaped.
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