METHOD AND APPARATUS FOR MEASURING ANGLE OF BEND, METHOD OF BENDING, AND APPARATUS FOR CONTROLLING ANGLE OF BEND

摘要

An angle detector head (29) including a light-emitting section (113) and a pair of photodetectors (115, 117) is freely movable in X, Y and Z directions. The angle detector head (29) is placed in a most suitable position for measuring the angle of a workpiece. A press (1) applies pressure to bend the workpiece close to a predetermined angle, and the angle of bend is measured. The pressure is then removed to take the load off the workpiece, and the no-load angle is measured. The difference between the angles of the workpiece before and after the removal of pressure is determined and registered as springback.