US 7,607,329 B2
Method for free bending
Burkhard Heller, Leonding (Austria); Michael Kaever, Erlangen (Germany); and Nader Ridane, Dortmund (Germany)
Assigned to Siemens Aktiengesellschaft, Munich (Germany)
Filed on Mar. 17, 2006, as Appl. No. 11/385,050.
Claims priority of application No. 10 2005 012 384 (DE), filed on Mar. 17, 2005.
Prior Publication US 2006/0218984 A1, Oct. 05, 2006
Int. Cl. B21D 5/02 (2006.01); B30B 15/26 (2006.01); B21C 51/00 (2006.01); G06F 15/46 (2006.01)
U.S. Cl. 72—31.11  [72/389.3; 72/389.4; 72/702; 100/50; 100/257; 700/165; 700/206; 364/476.01; 364/474.07] 12 Claims
OG exemplary drawing
 
1. 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.