| 摘要 |
PURPOSE:To enable the smooth entry of melted material into a cavity and to prevent the sticking of smear to molded articles so as to upgrade the appearance thereof, by exhausting a gas and extraneous oily substances in the cavity by suction during a period between the completion of closure of a mold and the start of injection. CONSTITUTION:When two side members 1a and 1b of a mold 1 make contact with each other, a limit switch 2 operates to open a solenoid valve 3 for 10sec, for instance, whereby the cavity of the mold 1 is made to communicate with a vacuum tank 5 through the intermediary of a vacuum hose 4. Thereby a gas and oily substances in the cavity are sucked into the vacuum tank 5, and further they are sucked by a vacuum pump 6 to be discharged outside. After the solenoid valve 3 is closed and thereby the vacuum suction is stopped, a stroke of normal injection molding proceeds, and the above-stated suction discharge is conducted after the mold is closed again. A high pressure usually required for making resin enter the corner part of the cavity in injection becomes unnecessary, and such a disadvantage as the impairment of the appearance of molded articles is eliminated, since the oily substances are exhausted completely. |
