| 摘要 |
PROBLEM TO BE SOLVED: To reduce the occurrence of uneven deformation in the design surface of a hollow structure caused by the shrinking of a foamed material after its foaming expansion. SOLUTION: Foamed materials 15 and 16 foamed by heating are held by a holder 11 on the shutting-off surface of a hollow section 7, then the foamed materials 15 and 16 are foamed by externally heating, and the hollow section 7 is shut off by filling the shutting-off surface with foamed bodies 15A and 16A. The first foamed material 15 is held in the holder 11 position corresponding to the non-design surface back surface part of the hollow section 7 and the second foaming material 16 having a foaming rate higher than that of the first foaming material 15 is held in the holder 11 position corresponding to the design surface 5A back surface part of the hollow section 7. |
