Cavity temperature control in plastic injection molding

A new approach for controlling part cooling in plastic injection molding is developed using a PI controller and coolant flowrate as the manipulated variable. The method uses an average part surface temperature within the mold as the setpoint parameter. A mechatronic system was developed for providing variable coolant flowrates. The control strategy was simulated using plant models, and then implemented and tested on a 50 tonne injection molding machine with good closed loop performance.