| 摘要 |
PURPOSE:To improve rigidity and shape accuracy of a shell mold for casting in the stage of adhering a pair of half-split shell mold materials and molding the shell mold by incorporating reinforcing rods into the half-split molds and utilizing the same as receiving seats for bonding. CONSTITUTION:Two reinforcing rods 22 are disposed with a pattern part 21 for a cam shaft formed on a pattern plate 20 in-between in the stage of casting a cam shaft by using a shell mold for casting. Receiving members 24 which are receiving seats for bonding are fixed to the plural positions on the top surface of the rods 22. After such pattern plate 20 is heated in an electrical furnace, the plate is set in a dump box 27 and chillers 30 are attached to the prescribed parts of the pattern 21. Resin sand 31 is put into the box 27 and after the sand is molded and melt-stuck, the resin sand layer is parted, calcined and cured, by which a half-split shell mold 32 is manufactured. Two pieces of such molds are combined and bonding pins 34 are press-welded to the members 24. Both half- split molds are adhered and the shell mold having the excellent rigidity provided by the reinforcing rods and having excellent shape accuracy is molded. |
