(A) study on the feedback controller design of mold filling process for plastic injection molding machine

Abstract

It is proposed to examine the parameter variation depending on the input magnitude and the control effect according to the control type using the plastic injection molding machine. During the filling process which is one process of its 5 processes per cycle, ram velocity is controlled to trace desired velocity profile. First, dynamic equations of the filling process are formulated, taking into account the non-linearity of hydraulic control system, non-Newtonian flow of molten polymer in nozzle and cavity. Second, several unmeasurable coefficients included in the dynamic equations are determined by the parameter optimization, based upon the minimization of errors between the measured and the predicted machine response, using the Direct Search Method. The variation of unmeasurable parameters will also be examined by changing input magnitude because nonlinear system shows different response according to the input magnitude. Third, experiment and simulation using the estimated unknown parameters are performed according to the control type which are Proportional, Proportional \& Integral, Proporional \& Derivative, and Proportion \& Integral \& Derivative control. And finally, the examination is performed to discuss the result between experiment and simulation at each control type.