Patent ID: 7607329

Claim:
A free bending process, comprising: prescribing a bending angle about which a workpiece is to be bent; bringing the workpiece into contact with a bending edge of a lower die about which the bending angle is to be formed, the workpiece arranged as a sheet metal plate relative to the lower die; executing a first bending process step including bending the sheet metal plate across the bending edge by moving a bending punching tool relative to the lower die for generating a current bending angle of the sheet metal plate; measuring the generated current bending angle at least after executing the first bending process step; executing further bending process steps each corresponding to the first bending process step; determining during the further bending process steps a plurality of bending forces to be applied by the bending punching tool for achieving the prescribed bending angle relative to a trajectory of the bending punching tool; creating a measuring curve including the determined bending forces related to the trajectory; determining an angle deviation from the current bending angle and the prescribed bending angle; calculating a correcting parameter based on the determined angle deviation, the created measuring curve and a model calculation representing the free bending process; and executing at least one final bending process step corresponding to the first bending process step based upon the calculated correcting parameter.