| 摘要 |
PURPOSE:To mold the peripheral wall of a boss wall in a large thickness, by a method wherein, when blow-molding a boss hole, a molding pin for the boss holes is projected from a wall surface of a mold, a projected part is provided in proximity to the pin, and the projected part is retracted into the mold at the time of blow molding. CONSTITUTION:A parison P is inflated and is defored to conform to the inside wall surface of a metallic mold 1. As the inflation proceeds, the parison P comes into contact with a tip part of the molding pin 2, is deformed into the shape of a mount, and thereafter it comes into contact with a tip part of an auxiliary sliding pin 4. When the pin 4 is retracted, the peripheral wall of the boss hole is molded in a large thickness. Accordingly, the peripheral wall of the boss hole thus molded has a large thickness, and can sufficiently endure at the time of fitting a screw. |
