Patent ID: 7344369
Filing Date: 2008-03-18
Classification: G05B

Abstract:
1. A controller of an injection molding machine having an injection screw axially moved by a servomotor at a variable injection velocity in an injection process, comprising: setting means for setting changeover conditions for changing over the injection velocity at respective sections of the injection process, and values of the injection velocity for the respective sections; means for successively outputting a motion command for the servomotor at every sampling period in accordance with the value of the injection velocity set for each of the respective sections; determining means for determining whether or not one of the changeover conditions is met at every sampling period; changeover means for changing over the injection velocity to a set value when said determining means determines that one of the changeover conditions is met; calculating means for calculating a compensation amount as a displaced motion amount of the injection screw caused by a time lag between a point in time when the changeover condition is actually met and a point in time when said determining means determines that the changeover condition is met at the sampling; and compensating means for compensating the motion command in at least one subsequent sampling period after said determining means determines that the changeover condition is met based on the calculated compensation amount.