| 摘要 |
PURPOSE:To stably provide films with little ununiform thickness by a method wherein a heater, which allows to set the temperature profile different in width direction, is arranged in the width direction near die lips and the thickness of films in the width direction is automatically controlled by means of a temperature sensor and a thickness sensor. CONSTITUTION:A heater 9 for controlling ununiform thickness is provided in the width direction near die lips 3 and electrically connected to a controller 11, to which a temperature sensor 10 arranged near the die lips 3 is electrically connected. The controller 11 passes electrical current through the heater 9 in accordance with the target temperatures of respective blocks so as to perform the temperature setting. After the temperature setting by the heater 9, the temperature of the molten resin extruded through between the die lips 3 is changed in response to the target temperatures of the respective blocks of the heater 9. When the difference between the temperature profile of molten resin and the target temperature profile becomes smaller than the certain value, the controller 11 performs the new setting of the target temperature profile on the basis of the difference between the ununiformity profile measured by a thickness sensor 12 and the target ununiformity profile. |
