Method for correcting a folding operation and folding press

A method of correcting a bending operation performed by a press brake of the type comprising a fixed beam, a movable beam, displacement means for displacing the movable beam resting on two side frames integral with the fixed beam, sensors, associated respectively with the two side frames, measuring the forces exerted by the said displacement means on the said side frames, deformation compensation cylinders associated with one of the two beams, and an electronic control device controlling the displacement of the movable beam between a top dead centre and a bottom dead centre, wherein a calibration nomogram is pre-recorded in the memory of the electronic control device using very short calibration pieces, the said nomogram establishing a correspondence between the forces measured by the sensors associated with the side frames and the pressures that can be applied to said compensation cylinders of the beam carrying them, in order to keep the said beam substantially straight, and wherein, during a subsequent bending operation, pressures resulting from the said nomogram are applied to the said compensation cylinders, according to the forces measured at the said sensors.