| 摘要 |
An excessive load detection device for an injection molding machine capable of detecting an excessive load exerted on the injection screw when the screw is driven with resin remaining unmolten in the heating cylinder. An output torque of the servomotor for axially moving the screw is limited to a predetermined value by a torque limiter and the screw is driven to move forward in a direction of injection by a predetermined amount at a predetermined velocity. If reference time elapses before the axial motion of the set amount is completed or a position deviation exceeds a reference value, it is determined that the remaining resin has low fluidity to cause an excessive load on the screw and an alarm is issued. When the axial motion of the screw is completed without an alarm, the screw is moved backward and forward alternately predetermined times. A servomotor for rotating the screw is driven in the same manner to detect an excessive load on the screw. Since the excessive load on the screw is directly detected, the excessive load is securely detected.
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