| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of a gas default by suppressing remaining unsolidified sand inside a gas passage tube and securely discharging pyrolysis gas outside a sand mold.SOLUTION: A sand mold 10 is formed by a lamination method of: spreading sand S to form each layer L having a predetermined thickness in the inner space of an elevator 5; solidifying a desired portion of the sand S in the layer; and laminating the layers one by one. In the vicinity part of cores 13a, 13b and a mold cavity part 16 of the sand mold 10, a gas passage tube 15 is arranged and formed. The gas passage tube 15 includes an opening part 15a communicating with the outside of the sand mold 10 and a lid part 15b for closing the opening part 15a. After discharging the unsolidified sand S that remains inside the gas passage tube 15 through the opening part 15a, the opening part 15a is closed by the lid part 15b to discharge pyrolysis gas outside from inside the gas passage tube 15. |
