| 摘要 |
PURPOSE:To prevent the reciprocating movement of a lunger from being checked by the synthetic resin entering the gap made between the plunger and a material charging chamber in a transfer molding consisting of a pair of molds equipped with molding cavities and the plunger reciprocatingly inserted in the material charging chamber provided on either one of both the molds. CONSTITUTION:On the outer peripheral surface of a plunger 9, a plurality of streaks of grooves, the starting end 10a of each of which locates at the region near the tip surface 9a of the plunger are engraved so as to open the terminal part 10b of each streak of groove extending spirally from its starting end into open air. |
