Supplemental bending method for correcting already bent workpiece, and apparatus for determining information for supplemental bending on the workpiece

A method of effecting a supplemental bending operation on an initially bent workpiece having a centerline extending between opposite ends thereof and having been subjected to an initial bending operation at an initial bending position selected along the centerline, said supplemental bending operation being effected for correcting a relative position between the opposite ends of said initially bent workpiece, said method comprising the steps of:

• determining an actual relative position between said opposite ends of said initially bent workpiece, and determining, on the basis of the determined actual relative position, a value of at least one supplemental bending parameter used for effecting said supplemental bending operation on said initially bent workpiece, for reducing an error between said actual relative position and a nominal relative position between opposite ends of a product to be obtained by said supplemental bending operation, said at least one supplemental bending parameter including one of a supplemental bending position and a supplemental bending amount when the other of said supplemental bending position and said supplemental bending amount has been determined as known, and both said supplemental bending position and said supplemental bending amount when neither of said supplemental bending position and said supplemental bending amount has been determined as known, said supplemental bending position being different from said initial bending position, said supplemental bending amount being an amount of bending of said workpiece by said supplemental bending operation at said supplemental bending position;
• and
• performing said supplemental bending operation at the determined supplemental bending position, so as to achieve the determined supplemental bending amount.