SELF-TUNING CAVITY PRESSURE CONTROL OF INJECTION-MOLDING FILLING

Cavity pressure is an important process parameter for injection moldin g control. However, the nonlinear and time-varying behavior of cavity pressure cause some difficulties in implementing a control system base d on commonly used linear, time-invariant design strategies. In this w ork, the nonlinearity and time-varying characteristics of cavity press ure are examined for the mold filling phase. A self-tuning controller has been developed, implemented, and tested for both regulating and tr acking purposes over a wide range of conditions. It is found that the proposed control system can automatically adapt itself to different op erating conditions, yielding quite accurate control. (C) 1994 John Wil ey & Sons, Inc.