Patent ID: 6854967

Claim:
An electric injecting molder wherein an injection screw disposed in an injection cylinder is driven to move in forward and backward directions by an electric motor to inject resin material in said injection cylinder into a metal mold to fill said metal mold, said electric injecting molder comprising: control means for velocity-controlling said electric motor when the resin material is filled into said metal mold but pressure-controlling said electric motor when the resin material is replenished for shrinkage of the resin after the resin material is filled; position detection means for detecting or estimating the position of said injection screw in the forward and backward direction; velocity detection means for detecting or estimating the velocity of said injection screw in the forward and backward direction; and force detection means for detecting or estimating the force applied to the resin material in said metal mold, and that said control means performs changeover from the velocity control to the pressure control after a position detection value from said position detection means reaches a predetermined position set in advance, and corrects, at least before the changeover from the velocity control to the pressure control upon the velocity control, a velocity target value for said injection screw in response to a force detection value from said force detection means so that the velocity target value for said injection screw may decrease as the force detection value increases to perform velocity feedback control of said electric motor so that the velocity detection value from said velocity detection means may be equal to the velocity target value, but determines, upon the pressure control, the velocity target value in response to a difference between the force detection value and a force target value to be applied to the resin material and velocity feedback controls said electric motor so that the velocity detection value may be equal to the determined velocity target value to perform control so that the force detection value and the force target value may coincide with each other.