熱可塑性樹脂の射出成形における適応制御―型内樹脂温度変化の解析―
Adaptive Process Control in Injection Molding-Prediction of the Temperature Variation of Polymer in the Cavity-
焼本数利・前川善一郎・_田泰以・酒井忠基
Yakemoto, Kazutoshi / Maekawa, Zenichiro / Hamada, Hiroyuki / Sakai, Tadamoto
Product quality and consistency in the injection molding process are largely dominated by the temperature variations of the mold wall or of the polymer inside the barrel. As a critical step for the development of process control to solve the fluctuations in product quality caused by temperature variations, a new method to predict the temperature variation of polymer in the cavity was investigated.
An equation to predict the temperature variation of polymer in the cavity was derived by using heat conduction analysis. This equation is believed to be adequate in accuracy, reliability, and applicability to process control. In this derivation, the conduction heat transfer during the filling and holding pressure stage, and the viscous dissipation during the filling stage were investigated.
The validity of the equation was investigated experimentally by using GPPS, PP, and POM under the conditions of varying mold temperature and of varying polymer temperature inside the barrel. And the measured and calculated temperature variations of polymer in the cavity were compared.
As a result, the temperature variation of polymer in the cavity, which may practically happen during the injection molding process, could be estimated with accuracy by the equation presented in this study. And the equation could be applied to predict product weight fluctuations in advance of the filling stage. So, it was confirmed that the prediction method presented in this study can be applied effectively to the adaptive process control.
Key words: Injection molding / Polymer temperature / Mold wall temperature / Conduction heat transfer / Process control