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AssigneeToray Industries, Inc.
InventorsHajime Hirata, Masatsugu Uehara, Yasuhiro Nakai, Jiro Terao
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A method of controlling the thickness of sheets manufactured by the extrusion of a material from a die having a plurality of thickness adjusting means by repeating, at specified timings, the following steps of 1) measuring the distribution of thickness of the sheets in lateral direction, 2) evaluating a predicted future variation in sheet thickness by using a specified evaluation function and based on a process model representing a relation between the amount of operation and the sheet thickness and sheet thickness measured values and leading an operating amount time series to minimize the evaluation function, and 3) outputting at least the initial amount of operation of the led operating amount time series to the thickness adjusting means.
A method of manufacturing a sheet, in which a raw material is extruded and molded into a sheet using a die with plural thickness adjusting means and the thickness of said sheet is controlled by controlling the manipulated variables applied to said thickness adjusting means, characterized by repeating, at predetermined intervals, a step of measuring the thickness distribution of the sheet in the transverse direction, a step of deriving manipulated variable time series in which a predetermined evaluation function for evaluating the future sheet thickness changes predicted based on said measured values and on a process model expressing the relation between said manipulated variables and sheet thickness values becomes a minimum value, and a step of delivering at least the first manipulated variables of the derived manipulated variable time series to said thickness adjusting means.
A device for controlling sheet thickness, which delivers manipulated variables obtained based on the measured sheet thickness values at respective portions of a sheet in the transverse direction measured by a thickness gauge to sheet thickness adjusting means at corresponding positions;
A program, for letting a computer perform the action of repeating, at predetermined intervals, a step of entering the measured thickness values at the respective portions of a sheet in the transverse direction, a step of computing the differences between the target thickness values and the measured thickness values at the respective portions, and a step of computing the manipulated variables to be applied to thickness adjusting means based on the said differences at the respective portions, characterized in that the step of computing manipulated variables includes a step of deriving manipulated variable time series in which a predetermined evaluation function for evaluating the future sheet thickness changes predicted on said measured values and on a process model expressing the relation between said manipulated variables and sheet thickness values becomes a minimum value, and a step of delivering at least the first manipulated variables of the derived manipulated variable time series to said thickness adjusting means.
A sheet obtained by extruding and molding a raw material using a die with plural thickness adjusting means, characterized in that the power spectrum of the thickness profile of the sheet in the transverse direction expressed by the following formula
Dependencies are inferred from the claim text.