| 摘要 |
<p>PROBLEM TO BE SOLVED: To control accurately the thickness of each of the layers of a multilayer film by effecting control in a short time against significant process variations such as condition change or the like, when the specified thickness of each of the layers of the multilayer film begins to be obtained. SOLUTION: A film thickness adjustment means for a die 1 which molds the multilayer film 5 from a molten resin, calculates an operation output through a specified control action based on data relative to the thickness of each of the layers detected at each of measuring points corresponding to plural adjustment units, for operating a discharge amount for every specified width from the die 1, which are arranged in every layer of the film 5 across the entire width of the die 1. In addition, a multipoint control means consists of plural control loops for controlling the thickness of each of the layers through applying the operation output to each of the adjustment units and controlling the thickness of each of the layers. In the thickness control device for a multilayer film comprising these described means, the thickness of each of the layers of the multilayer film is intermittently controlled, and at the same time, the operation output to each of the adjustment units is applied to each of the layers. The total layer thickness of the multilayer film 5, that is, the gross thickness and the surface layer thickness are measured and the thickness of a core layer is obtained by subtracting the thickness of the surface layer from the gross thickness.</p> |
