| 摘要 |
PURPOSE:To efficiently prepare a flanged pipe made of a synthetic resin by positioning a single parison having the length corresponding to that of a molded product between split molds and clamping the lower end part of the parison in such a state that a cavity for a flange is closed from below to integrally mold a thick flange. CONSTITUTION:After a main core 11 is allowed to racede to supply a molten resin A to a die head A, a bis-core 13 is allowed to rapidly recede to open a parison emitting port 12 and a thick-wall parison part P1 having predetermined length is extruded as the max. thick-wall dimension. At this time, a hole P3 for inserting a slide pin D is formed to the center of the parison part P1 by the tip 13a of the core 13. Thereafter, the sub-core 13 is returned to the original position and the opening demising of the parison emitting port 13 is adjusted to extrude a thin-wall parison part P2. Subsequently, the upper end of a parison P is clamped by a split mold C to be received in the cavity thereof and the shaft part 20 of the slide pin D is pushed in the passing hole P3 to perform blow molding and the thick-wall part P1 is outwardly extruded to be expanded in such a state that a cavity 31 for a lange is closed and the lower end part of the parison is clamped to integrally mold a thick-wall flange F. |
