| 摘要 |
PURPOSE:To prevent the blow-back of molten metal and the formation of blowholes by constituting the pattern by the molding having continuous vent holes among foamed resin particles thereby letting the gas evolved by pouring through the continuous vent holes. CONSTITUTION:A binder solution is compounded in foamed resin particles 1 having closed cells, whereby a binder layer 2 is evenly formed on the surfaces of the resin particles 1. Next, these are packed in the specified mold and hot air is sent into the mold, at the same instant of which the mold is pressed. When the foamed resin particles 1 are partially bonded and the temperature has lowered to the deformation temperature or lower of the binder layer 2, the mold is parted. This yields the pattern of good air permeability having the continuous cells 3. Hence, the combustion gas evolved through pouring passes through the cells 3 and is discharged to outside the mold, thus its stagnation in the mold is obviated. |
