Method of manufacturing foam with a negative Poisson's ratio, involves applying isostatic pressure difference between inside and outside of chamber to collapse foam between flexible membrane and molding surface

NOVELTY - The method involves placing an open cell foam (12) on a molding surface. A flexible membrane (18) with the foam arranged within the chamber and is placed on the exposed surface of the foam to create a sealed chamber between the molding surface and the flexible membrane. An isostatic pressure difference is applied between the inside and the outside of the chamber to collapse the foam between the membrane and the molding surface. The foam is heated to a predetermined temperature and foam is cooled when collapsed. USE - Method of manufacturing foam with a negative Poisson's ratio. ADVANTAGE - Since the foam pad is heated before the isostatic pressure difference is applied, the ribs of the cells are softened before the cells are collapsed. The foam pad can be cooled after the pressure difference is applied to collapse the cells of the foam pad. The pressure difference need only be applied to collapse the foam pad and need not be maintained during the cooling process. DESCRIPTION OF DRAWING(S) - The drawing shows the sectional view of the apparatus for manufacturing foam. Packed mould (2) Tooling plate (10) Open cell foam (12) Temperature sensor (14) Flexible membrane (18)