Abstract: 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.

Abstract: 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.

Abstract: A method of manufacturing a sheet by extruding and forming a polymer by using a plurality of mouthpieces each having a thickness adjusting means, comprising the steps of varying the amount of operation applied to the thickness adjusting means along a specified time series pattern, measuring a thickness distribution in the lateral direction of the sheet, and rapidly and accurately determining the corresponding relation between the thickness adjusting means and a thickness measurement position based on the results of comparison between a variation in sheet thickness variation distribution thus obtained or the standard time series pattern of the variation in sheet thickness distribution and the time series pattern of the measured values of the thickness distribution.

Abstract: Recess portions each comprising one or a plurality of transverse grooves or a large number of dimples are disposed below the lowermost position of a meniscus under a steady operation state within a distance of 200 mm on the inner peripheral surface of the casting mold so that a solidified shell is gradually cooled and the cooling capacity of each inner surface of the casting mold is substantially inform.

Abstract: To provide a continuous casting method for a billet capable of stable casting without causing rhomboidity or side periphery deformation in the billet produced by continuous casting, in a casting mold used for this method, recess portions each comprising one or a plurality of transverse grooves or a large number of dimples are disposed below the lowermost position of a meniscus under a steady operation state within a distance of 200 mm on the inner peripheral surface of the casting mold so that a solidified shell is gradually cooled and the cooling capacity of each inner surface of the casting mold is substantially uniform.

Abstract: A method of oscillating a continuous caster mold at high frequencies comprises disposing a plurality of oscillators having substantially the same oscillating characteristic at appropriate intervals along or in the vicinity of a line where liquid metal contacts an inner lining of a mold, connecting the tip of each oscillator to the inner lining so that the axis of the oscillator extends at right angles to the surface of the inner lining, and supplying power from an oscillation generator to each oscillator so that the oscillation frequencies of any two adjoining oscillators are differentiated within the limit of 2 KHz. Thus, any two adjoining oscillators oscillate the inner lining at right angles to the surface thereof at mutually differentiated frequencies.