Patent ID: 8091608

Claim:
A method of forming a hollow sand core, comprising: placing a preform into a cavity defined in a mold, the preform having a predetermined configuration; introducing a granular material into the mold cavity and around the preform; establishing the granular material around the preform to form a sand core; deforming the preform in a manner sufficient to enable removal of the preform from inside the sand core; and removing the deformed preform from the sand core, thereby exposing a hollow portion of the sand core, wherein the preform is made from a shape memory polymer, and wherein prior to placing the preform into the cavity, the method further comprises: setting a permanent shape of the shape memory polymer; heating the shape memory polymer in its permanent shape to a temperature above its glass transition temperature, thereby rendering the shape memory polymer pliable; shaping the pliable shape memory polymer into the predetermined configuration; and cooling the shape memory polymer to set the predetermined configuration and thus a temporary shape of the shape memory polymer.