Patent ID: 8601848

Claim:
A bending device that bends a longitudinal workpiece, the bending device comprising: a bending mechanism that includes a bending die and a clamping die which rotates around the bending die, the bending mechanism clamping the workpiece with the bending die and the clamping die, and bending the workpiece by rotating the clamping die while twisting the workpiece at a predetermined twisting angle around a longitudinal axis of the workpiece; a fixing table on which a chuck mechanism that grips the workpiece is mounted; an articulated robot to which the bending mechanism is attached; and a control unit that controls the articulated robot, the bending mechanism and the chuck mechanism, wherein the control unit includes (i) a determination unit that determines whether or not the twisting angle is within a preset twisting angle range, (ii) a first control unit that controls the articulated robot to twist the bending mechanism holding the workpiece around a longitudinal axis of the workpiece when the determination unit determines that the twisting angle is within the preset twisting angle range, and (iii) a second control unit that, when the determination unit determines that the twisting angle exceeds the preset twisting angle range, controls the articulated robot to twist the bending mechanism holding the workpiece around the longitudinal axis of the workpiece within the preset twisting angle range, and then controls the chuck mechanism and the bending mechanism to repeat an operation of releasing and again clamping the workpiece, and further twisting the workpiece within the preset twisting angle range, to thereby twist the workpiece by the twisting angle.