BENDING METHOD USING PRESS-BRAKE, AND PRESS-BRAKE

摘要

PROBLEM TO BE SOLVED: To provide a bending method and a press-brake, which reduce a bending load in bending a platy work. SOLUTION: The bending method is used for bending a platy work W with a press-brake 1. Deflection of a punch 11 or a die 9 is generated in a state of concave curvature by the reactive force at the time of air-bending the work W. The punch 11 or the die 9 is pre-curved in a convex state with a curvature radius so as to correct the deflection. Bending of the work W is started in a state that the punch 11 or the die 9 is pre-curved in a convex state with a curvature radius that is smaller than the above curvature radius. When working of the work W is shifted from bending to bottoming, the curvature radius of the punch 11 or the die 9 is made larger so that the punch and the die are parallel with each other. Further, when bending the work at the vicinity of a target bending angle, pressurizing action and pressure-relaxing action by the punch and the die are alternately repeated for a proper number of times. COPYRIGHT: (C)2005,JPO&NCIPI