Patent ID: 7595013
Filing Date: 2009-09-29
Classification: B29C

Abstract:
1. A method for adjusting a reverse rotation amount of a reverse rotation process in an injection molding machine which comprises an injection screw having a check ring thereon for closing a resin passage by reverse rotating the screw in a direction reverse to rotation of the screw during metering, rotary driving means for rotationally driving the screw, axial driving means for driving the screw in an axial direction of the screw, and rotational force detecting means for detecting a rotational force acting on the screw, and carries out a reverse rotation process in which, during an interval after completion of a metering process until start of an injection process, the screw is caused to rotate in a direction opposite to that during metering process, the method comprising the steps of: rotating the screw in reverse by said rotary driving means during the interval from completion of the metering process until start of the injection process, and then moving the screw forward by said rotary driving means; detecting a reverse rotational force applied to the screw by said rotational force detecting means during forward movement of the screw; determining whether or not the resin passage is closed by said check ring based on the detected reverse rotational force for each molding cycle; increasing the reverse rotation amount of the screw for each molding cycle until said determination means determines that the resin passage is closed; and stopping an increment of the reverse rotation when the resin passage is determined to be closed, and setting the current reverse rotation amount as a setting value of the reverse rotation process.