| 摘要 |
PURPOSE:To obtain a core of rigid shape by such an arrangement wherein sheets of film are caused to closely contact with the interior of two split type metal molds which are closed and fastened, and the sheets of film are melted and positively fused together by heating wires embedded in the parting and they maintain sealed condition so that it withstands vacuum and decompression and the bag of film is filled up with dry sands by a vacuum pump. CONSTITUTION:Sheets of film 5a, 5b softened by a heater 14 are caused to closely contact with the surfaces of metal molds 3, 4 being sucked by a pump 12. Next, the upper mold 3 and lower mold 4 are joined and fastened and the sheets of film 5a, 5b are caused to fuse together in the vicinity of an inscribed portion, being heated by an electric heating wire, and a bag of core-like shape is formed. Dry sands 17 are sent into the bag from an injection hole 15 through a pipe 18. The interior of the core bag is made vacuous by a vacuum pump 19 through suction pipes 21a, 21b... arranged at all branches from the center of the core. As a result of this process, dry sands are compacted by vacuum condition and the core becomes rigid state. |
