| abstract |
PURPOSE:To produce easily a hollow casting, etc. with a repetitively usable core by filling fluid in the bag-shaped core of metallic foil, etc. to a prescribed shape, disposing the same in a matrix, charging a metallic melt, etc. and casting the hollow object, etc. CONSTITUTION:Fluid such as liquid nitrogen or the like is filled in a core 1 consisting of a bag-shaped body formed of metallic foil or plastic film to a prescribed shape and such core is disposed in a matrix consisting of top and bottom molds 5, 6. The core print parts 1a, 1b of the core 1 are fitted into the holes 7, etc. of the matrix and are thus set. The melt of aluminum, etc. or a plastic for casting such as PP or the like is charged in the matrix through a sprue (not shown), and is then cooled to solidify. A valve 3 is opened to extract the fluid from the inside of the core 1, and the shrunk core 1 is drawn to the outside from the holes 7; at the same time, the molds 5, 6 are removed and a hollow casting 8 of aluminum, etc. is obtd. |