SWITCHING PROCESS OF INJECTION DWELL PRESSURE OF INJECTION MOLDING MACHINE AND ITS DEVICE

摘要

PURPOSE:To enable a molded object to be obtained always stably, while the molded defect such as burrs or the sink marks due to insufficient filling, etc., is eliminated by a method in which ultrasonic wave is radiated inside of a cavity from the outside of a mold in the filling process into the mold cavity with molten resin, and then the existence of packed molten resin is detected, and after the existence of resin has been detected, the filling process is switched to dwell pressure process. CONSTITUTION:Molten resin P is injected in a cavity 37 through a nozzle 53, while a ram 47 is moved in left direction. Ultrasonic wave is radiated on the position S to be filled finally in the cavity 37 from a prove 75, and then the prove 75 receives reflecting wave and a prove 76 receives penetrating wave. Said reflecting wave or penetrating wave is amplified by an amplifier 79 through an ultrasonic wave generator 77, and the wave pattern of actual reflecting wave or the penetrating wave is compared with the normal wave pattern of the reflecting wave or the penetrating wave in a comparator 81. The filled state in which the molten resin has entered into the position S to be filled finally is judged as normal state. A signal of said normal state is brought into a process-switching device 85 and is switched to the pressure-setting signal generator 89 for dwell pressure-process.