| 摘要 |
PURPOSE:To make it possible to maintain the internal part of a cavity in a high vacuum state even in time of a low speed packing by making high speeds evacuation of the air etc. flowing into the cavity just befoe the cavity has been filled with molten resin. CONSTITUTION:The instant when molds 1, 2 are closed, a limit switch 21 operates, an electronic control device 20 drives a solenoid value 16, the piston 13 opens the valve 6, the cavity 3 is connected to a vacuum tank 9 and the air begins to be evacuated. A timer 22 is set to the time necessary to let the internal space of the cavity 3 arrive at a high vacuum. Preparations are made by a signal of the limit switch 21 and the injection of resin commences from the spool 4 at the specified time elapse. When molten resin arrives at the position of the resin detector 7, the temperature rises suddenly, therefore, the arrival of the molten resin is detected, the electronic control device 20 drives the solenoid 16 to close the valve 6. |
