抄録
The quality of manufactured wide films is determined by the flatness of their thickness. In the lip-heater method, the thickness control is performed by realizing a uniform distribution of melted polymer flow velocity in the gap between die lips and for this purpose one hundred or more regulating heaters are used. In the previous paper, a design method is proposed for such control systems based on a concept of fundamental subsystems. This paper aims at proposing a parameter adjusting mechanism of the obtained controllers to cope with the change of operating conditions. As the causes of the change, the following three factors are taken into account: (1) casting speed, (2) polymer extrusion rate and (3) lip gap. Thickness of films can be determined through the combinations of these three factors. In the paper, it is shown through the analysis of experimental data that the change of the dynamics of the thickness process model can be well expressed simply by the changes of the gain and the dead time of the process. Based upon this fact, a pre-setting type control method is described which enables to realize a uniform control stability for any operating conditions. In this method, before starting manufacturing, the necessary matrices to be used in the controllers are easily obtained from the matrices calculated beforehand. The effect of the control method is shown by simulation calculations.
