JPS57165112A - Controlling method of rolling mill - Google Patents

Abstract

PURPOSE:To obtain uniform sheet thickness, by controlling a finishing mill depending on the fluctuation of sheet thickness in a planetary mill. CONSTITUTION:A data fetching device 15 fetches the screw-down position SA and the screw-down load PA of a present finishing roll 5 from a screw-down deivce 14 at the time when a timing (i) is given by a timing device 12. PX is obtained from the fetched PA and SA so that the sheet thickness of a sheet to be rolled is hO after rolling. The difference DELTAPxi between Px and a standard rolling load Po is inputted to a differentiation device 17 from the device 15 in order to output the difference between DELTAPxi and DELTAPxi-1, as a DELTADELTAPxi, from the device 17. A screw-down position S is calculated to make the sheet thickness hO of the material to be rolled constant after rolling by rolling it with the finishing roll of the next timing by means of a screw-down position commanding device 19, by predicting DELTAPj of the next controlling timing with the aid of integration device 18. Thus the sheet thickness after rolling is kept constant by removing the periodical fluctuation of the sheet chickness before rolling, by operating the device 14 in accordance with said S.