DIE, PUNCH, METHOD FOR DETECTING BENDING ANGLE AND BENDING MACHINE

摘要

PROBLEM TO BE SOLVED: To exactly detect a bending angle in bending a work with a noncontact type detector and also to improve over length accuracy of bending. SOLUTION: In a bending machine provided with a die D provided with a die groove DV for bending a planar work W and a punch P which is relatively freely movable in the approaching and separating direction to the die D in order to press the work W against the die groove DV, a half mirror 39 for dividing a laser beam LB which is oscillated with a laser length-measuring device 41 into the plural beams and making them reflect to the neighborhood of the bending part of the work W is provided on at least one of the punch P and the die D. A calculating means for calculating the inclined angles of both side faces of the work W based on the distances from the laser length- measuring device 41 to plural laser irradiated points on the work W and calculating the bending angle of the work W based on each of these calculated inclined angles is provided.