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| Vacuum forming is used to provide final shapes fabricated from thermoplastic polymeric materials. The low melting point of these materials permits the sheet stock to be heat softened, clamped to a mould that can be evacuated, and deformed to the mould shape by the differential pressure across the sheet. As indicate in the right diagrams, the vacuum deformation process may be assisted by a plug. |  |
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| Uniform
heating and loading of the thermoplastic polymer can produce shapes of
constant wall section without re-entrant faces. The plastic deformation
of the polymer tends to orient the macromolecules along the flow direction,
as a result of which the mechanical properties of the component may be
non-isotropic.
From: "Manufacturing with Materials," Edwards and Endean (Eds.), Butterworth (1990) |
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