| 摘要 |
PROBLEM TO BE SOLVED: To provide a mold assembly for injecting a molten material in a cavity formed by mold clamping under predetermined pressure to precisely injection-mold a precise part having an undercut. SOLUTION: The mold assembly is equipped with a cylindrical body 120, which has an undercut molding part 1,231 for molding a shape incapable of being demolded in a mold opening direction formed to its outer peripheral surface 123, and a diameter expanding member 112, which enters a cavity 121 from the opening 122 of the cylindrical body 120 to expand the outer diameter of the cylindrical body 120 and relatively freely advances and retreats with respect to the cavity 121, and the diameter expanding member 112 is located in the cavity 121 at the time of mold clamping but drawn out of the cavity 121 at the time of mold opening. The cylindrical body 120 comprises a metal having longitudinal elastic modulus of which the value is not less than a predetermined pressure value and the outer diameter expanded by the diameter expanding member 112 thereof is contracted when the diameter expanding member 112 is drawn out of the cavity 121. COPYRIGHT: (C)2006,JPO&NCIPI
|
