| 摘要 |
PURPOSE:To facilitate the withdrawal of a disc at a hole section by providing a spool bush movable with a die closed while a special pundh is provided facing it to enables the accurate arrangement of a hole at the center of the disc molded. CONSTITUTION:After the clamping of a die, a nozzle 38 is pressed on a recess 8a of a sprue bush 8 and a melted resin is injected into a disc-shaped cavity. After the elapse of a specified time, the nozzle 38 is retracted and then, a liquid is forced into a cylinder 31 provided on the first member 13 on the mobile side to stick out a punch 29 through a piston 32. With this, the sprue bush 8 is retracted and a hole is made on a disc immediately after molded with the same diameter as the tip of the punch 29 and the tip 8a of the sprue bush 8. After the opening of the die, an ejector pin 30 provided at the center of the punch 29 is sticked out to facilitate the withdrawal of the disc at the hole section. |
