| 摘要 |
PURPOSE:To shorten drastically correcting time of a mold by preventing generation of sink marks, by accelerating partial foaming by sending an inducing agent of the foaming into a plastic material through the tip of a core pin through a passage formed in a core pin in the course of molding. CONSTITUTION:The inside of a cavity 3 is filled with a plastic material in a molten state and then and inducing agent of the foaming is sent into a plastic material through the tip of a core pin 4 through a passage 8. Although time directly after filling of the plastic material is preferable for timing of this sending-in, the same is controlled according to a kind of the plastic material to be filled up and a thickness of a molded product. A state of protrusion into the cavity 3 of the core pin 4 is controlled under various conditions. After partial foaming has been accelerated o the plastic material with the inducing agent of the foaming, the plastic material is solidified by cooling a a mold and when the plastic material is solidified, the molded product is taken out by separating a male and female molds 1, 2 form each other. A base part 10 is formed on the molded product molded like this and a sink mark is not generated on the surface of the boss part 10. |
