| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation of shrinkage and gloss at a surface side corresponding to a groove part by engraving a weak part to be broken into the shape of a groove formed on an inner surface side of a coating part, into the shape of a groove. SOLUTION: An air bag cover is provided with a groove part 40 integrally molded in advance. A thickness of a bottom 36 of the groove part 40 is 1/3 of a general thickness t0 of a base part of the air bag cover. By applying the thickness of the bottom 36, a milling blade 56 having a diameter smaller than a width of the groove part 40 is used for further engraving the groove on the bottom 36 of the groove part 40. The groove has two stages, and a cut burr 33 is formed on a boundary part 32 between the milling blade 56 and the bottom 36. Then a mold 58 is pressed for chamfering while levelling off the cut burr 3, and a side wall having the approximately S-shaped cross section is formed by shaping. On this occasion, since a point of the mold 58 does not reach a bottom part 31, the change of gloss is not generated at a surface side. |
