| 摘要 |
PURPOSE:To improve the escape of air and gas by a method wherein a space between a backing plate and a bottom plate is enclosed under the condition that molds are closes and evacuated during the injection of plastic. CONSTITUTION:An ejector plate upper 5 and an ejector plate lower 6 are arranged in a space between a backing plate 10 and a bottom plate 11, which is enclosed by a spacer block 9, a plate 13 and a ring 14. A hose attaching port 15, through which a vacuum generating device 16 is connected, is provided on the side of the plate 13. When molds are closed, a solenoid valve 18 is opened by means of a sequence timer 19 so as to generate vacuum and, after that, injection is started. The air in cavities and generated gas are sucked through clearances between ejector pins 8 and a movable retainer plate 2 in a vacuumized space between the backing plate 10 and the bottom plate 11. After the finish of injection, mold closing is done. At that time, before the start of the pushing-up of the ejector plate lower 6 by an ejector rod 7, the solenoid valve 18 is closed by means of the sequence timer 19, resulting in stopping the actuation of the vacuum generating device 16 so as to release vacuum. The removal of a product from the molds can not be hindered by vacuum. |
