Parts with intricate structures can be formed using shape memory polymers as the forming structures. Shape memory polymers are those polymers which after being shaped into a permanent structure may by deformed into another metastable shape and quickly cooled below the switching temperature.  It will stay frozen in this metastable state until heated above the switching temperature.  Shape memory polymers include epoxies, acrylics, polystyrenes, and polyolefins. The shape memory polymer is formed into its permanent shape with the appropriate intricate structure. It is then deformed into a temporary, open structure and frozen in this state by cooling. The molding material is sprayed into this open preform. This molding material may include resins and composites.  After the molded material has solidified, the assembly is heated above the switching temperature, forcing the material into the desired structure. Once completed, the molded object is removed from the shape memory polymer mold, and the process can be repeated.  Berger et al, US Patent 7,727,450 (6/1/2010)

Comments