Patent ID: 7393481
Filing Date: 2008-07-01
Classification: B22D,B29C

Abstract:
1. A method for electric clamping using a die casting machine provided with a clamping unit having a fixed mold and a movable mold for forming a cavity together, and a core system for reciprocating a core between a retreating position and a position in which the core is fully drawn into the cavity using an actuator provided on the movable mold; and the clamping unit driven by a servo-motor to reciprocate the movable mold through a predetermined stroke and clamp the two molds together; the method performing a core-drawing-in process in which a core is drawn into a cavity in parallel with a clamping process in which the two molds are closed and clamped together, and the method comprising the steps of: setting a check point, for judging safety of the clamping process in advance, at a position that is nearer to the operational start position by a predetermined distance in the mold opening direction than a position of the movable mold when an operation to draw the core into the cavity is expected to be completed, wherein the core-drawing-in process and the clamping process proceed in parallel with each other in a straight course for reciprocating the movable mold; activating the core system and the servo-motor to start the operation to draw the core into the cavity in parallel with an operation to move the movable mold in the mold closing direction; detecting whether or not the movable mold reaches the check point; judging whether or not the core reaches the position in which the core is fully drawn in the cavity at a point of time at which the movable mold reaches the check point, and confirming the completion of the core-drawing-in process; and further continuing the clamping process of the molds if confirming that the core-drawing-in process is already completed.