Barrel temperature control during operation transition in injection molding

Injection molding barrel temperatures have slow responses. During the transitions between the machine's idle state and the operation state, significant temperature variations exist in the temperature zones. This leads to inhomogeneous melt temperatures and inconsistent product quality. This paper introduces this industrial problem and then presents a combined strategy using a feedback controller and an iterative learning feedforward (ILFF) controller to resolve the problem. The proposed strategy is implemented and tested on an industrial-sized reciprocating-screw injection molding machine. Experiments show that the combined control strategy has superior performance compared with that of the traditional feedback controller.