Patent ID: 8959967
Filing Date: 2015-02-24
Classification: B21D,C21D

Abstract:
1. A method for controlling a flatness of a first surface of a sheet material, the method comprising: (a) determining a first surface contour of the first surface of the sheet; (b) applying compressive stresses to one or more portions of the first surface of the sheet after the determination of the first surface contour of the sheet; (c) annealing compressive stresses in one or more portions of the first surface of the sheet after the determination of the first surface contour of the sheet; (d) determining a second surface contour of the first surface of the sheet after the compressive stresses have been applied to, and annealed from, the sheet; (e) comparing the second surface contour to a threshold flatness; and (f) performing (b)-(e) one or more times until the determined second surface contour is less than the threshold flatness.