| 摘要 |
PURPOSE:To provide a manufacturing method which effectively performs the pre-heating of a mandrel for an extrusion die when the extrusion molding of a synthetic resin pipe is started, an does not generate trouble such as the breakage of a heater built in the metal die or the wiring due to heat deterioration at the same time. CONSTITUTION:A mandrel 2 of a metal die for synthetic resin pipe, which is attached to an extruder, is pre-heated by inserting a cartridge heater 5 from the opening end side of the metal die in the mandrel 2 and connecting power. After the temperature rising is completed, the cartridge heater 5 is pulled out from the mandrel 2 and separated from the extrusion die, and then, the operation of the extruder is started. |
