| 摘要 |
PURPOSE:To obtain a blow molding method by which molding is easily performed and the productivity can be enhanced. CONSTITUTION:Pressure (Pj), volume and temperature (Tj) of the air of the inside of a parison 1 are grasped in every time by controlling pressure (Ph), volume and temperature (Th) of the air blow from an air tank 3 at high temperature. A pre-blow stage, a blow-up stage or a cooling stage in a molding process is judged from the grasped volume of the air of the inside of this parison 1. The parison 1 is set at pressure and temperature of the air suitable for each stage and molded. When the volume of moldings is made equal to the volume of the inside of the parison 1, solenoid valves 12, 13 are opened and a solenoid valve 11 is closed. Air is introduced from an air tank 4 at low temperature. The air is controlled so that the flow rate discharged from the parison 1 is made equal to the flow rate supplied from the air tank 4 at low temperature. When cooling is finished, the solenoid valves 11, 12, 13 are closed and the moldings are taken out. |
