| 摘要 |
<p>PROBLEM TO BE SOLVED: To properly and stably finish a molded sheet to a mirror surface state when a molten sheet to be extruded from a T-die is to be subjected to extrusion molding by a sheet molding machine. SOLUTION: In this control method, the molten sheet extruded from the T-die of an extruder is cooled to predetermined temp. by a first cooling roll and this molten sheet is molded into a sheet with predetermined thickness through a touch roll, a second cooling roll and a taking-over roll. In this case, the drive current (regenerative braking current) of a first servo motor 33 for driving a touch roll 30 and a first cooling roll 32 in a cooperative state and the drive current (effective value current) of a second servo motor 35 for driving a second cooling roll 34 are respectively detected and these detected current values A1, A2 are subjected to cooperative operation and, so that the value thereof becomes a limit value or less when tolerable dead band quantity is set to a limit value A0 in a balanced state or in the touch roll 30, the speed of the touch roll 30 is subjected to feedback control.</p> |
