| 摘要 |
PURPOSE:To facilitate a stopping accuracy of mold closing and a centering accuracy of a mold by forming a pre-blow air passage at a core disposed at a center of a die, and movably inserting a high pressure blow pin in the passage coaxially with the passage. CONSTITUTION:A parison 22 formed of thermoplastic resin as a base material is vertically extruded from a slit 20 of a die 10 and suspended between a male mold 24 and a female mold 26 heated to a predetermined temperature. Then, after a lower end of the parison 22 is pinched by a pinch unit to a bag state, pre-blow air of low pressure is introduced from a pre-blow air passage 30 into the parison 22. Then, after the molds are clamped, high pressure blow air is charged into the parison 22 from a high pressure blow pin 28 movably inserted into the passage 30 coaxially with the passage 30 into the parison 22 closed at upper, lower sides and periphery by both the molds 24, 26 thereby to complete a molded form of a final shape. |
