Workpiece bending method and workpiece bending apparatus

Abstract

workpiece bending method and a workpiece bending apparatus that allow setting of a trajectory of a bending implement based upon a pre-processed shape of a workpiece and an intended post-processed shape of the workpiece. The workpiece bending method bends a flange of a workpiece via a processing roller, and includes a step for obtaining a pre-processed angle of the flange before processing and a flange length of the portion of the flange to be bent; a trajectory determination step for determining a path (trajectory) of the processing roller based upon the pre-processed angle, an intended angle after processing, and the flange length; and a processing step for moving the processing roller in a prescribed direction in accordance with the path determined in the trajectory determination step and then bending the flange until the intended angle is achieved.

1 . A workpiece bending method for performing a bending process on an end portion of a workpiece by a processing tool, the method comprising:
 a step of obtaining a pre-processed angle of the end portion before processing and an end portion length of a bent portion of the end portion;   a trajectory determination step of determining a trajectory of the processing tool on the basis of the pre-processed angle, an intended angle after processing, and the end portion length; and   a processing step of moving the processing tool in a predetermined direction on the basis of the trajectory determined in the trajectory determination step and bending the end portion up to the intended angle.   
     
     
         2 . The workpiece bending method according to  claim 1 ,
 wherein, in the trajectory determination step, a difference between the pre-processed angle and the intended angle or a value obtained by dividing the difference by the end portion length or both are calculated as a trajectory determination value, and   the number of times of bending and the bending angle of each step are calculated from a trajectory number determination map in which the trajectory number representing the number of times of bending to be bent in stages from the pre-processed angle to the intended angle is determined in stages depending on the magnitude of the trajectory determination value, and from the calculated trajectory determination value.   
     
     
         3 . The workpiece bending method according to  claim 1 , wherein when the shape of the end portion of the workpiece is different in the movement direction of the processing tool, in the trajectory determination step,
 the trajectory of the processing tool is determined   on the basis of the pre-processed angle, the intended angle, and the end portion length of a first cross section of the end portion viewed in the movement direction of the processing tool, and   on the basis of the pre-processed angle, the intended angle, and the end portion length of a second cross section different from the first cross section of the end portion viewed in the movement direction of the processing tool.   
     
     
         4 . The workpiece bending method according to  claim 3 , wherein a difference between the pre-processed angle and the intended angle of the first cross section, a value obtained by dividing the difference by the end portion length or both are calculated as a first trajectory determination value,
 a difference between the pre-processed angle and the intended angle of the second cross section, a value obtained by dividing the difference by the end portion length or both are calculated   as a second trajectory determination value, and   the number of times of bending and the bending angle of each step are calculated from a trajectory number determination map in which the trajectory number representing the number of times of bending to be bent in stages from the pre-processed angle to the intended angle is determined in stages depending on the magnitude of the trajectory determination value, and from the calculated first and second trajectory determination values.   
     
     
         5 . The workpiece bending method according to  claim 4 , wherein in the trajectory number determination map, values for determining an upper limit value for each trajectory number are determined, and
 the bending angle is calculated in each step by reflecting a deviation with respect to the upper limit value in the range to which the trajectory determination value plotted in the trajectory number determination map belongs.   
     
     
         6 . A workpiece bending apparatus which performs a bending process on an end portion of a workpiece by a processing tool, the apparatus comprising:
 a control unit which obtains a pre-processed angle of the end portion before processing and an end portion length of a bent portion of the end portion, and determines a trajectory of the processing tool on the basis of the pre-processed angle, an intended angle after processing, and the end portion length; and   a robot which moves the processing tool in a predetermined direction on the basis of the trajectory determined in the control unit, and bends the end portion up to the intended angle.   
     
     
         7 . The workpiece bending apparatus according to  claim 6 , wherein the control unit calculates a difference between the pre-processed angle and the intended angle or a value obtained by dividing the difference by the end portion length or both, as a trajectory determination value, and
 the number of times of bending and the bending angle of each step are calculated, from a trajectory number determination map in which the trajectory number representing the number of times of bending to be bent in stages from the pre-processed angle to the intended angle is determined in stages depending on the magnitude of the trajectory determination value, and from the calculated trajectory determination value.   
     
     
         8 . The workpiece bending apparatus according to  claim 6 , wherein, when the shape of the end portion of the workpiece is different in the movement direction of the processing tool,
 the control unit determines the trajectory of the processing tool,   on the basis of the pre-processed angle, the intended angle, and the end portion length of the first cross section of the end portion viewed in the movement direction of the processing tool, and   on the basis of the pre-processed angle, the intended angle, and the end portion length of the second cross section different from the first cross section of the end portion viewed in the movement direction of the processing tool.   
     
     
         9 . The workpiece bending apparatus according to  claim 8 , wherein a difference between the pre-processed angle and the intended angle of the first cross section, a value obtained by dividing the difference by the end portion length or both are calculated as a first trajectory determination value,
 a difference between the pre-processed angle and the intended angle of the second cross section, a value obtained by dividing the difference by the end portion length or both are calculated as a second trajectory determination value, and   the number of times of bending and the bending angle of each step are calculated, from a trajectory number determination map in which the trajectory number representing the number of times of bending to be bent in stages from the pre-processed angle to the intended angle is determined in stages depending on the magnitude of the trajectory determination value, and from the calculated first and second trajectory determination values.   
     
     
         10 . The workpiece bending apparatus according to  claim 9 , wherein in the trajectory number determination map, values for determining an upper limit value for each trajectory number are determined, and
 the bending angle is calculated in each step by reflecting a deviation with respect to the upper limit value in the range to which the trajectory determination value plotted in the trajectory number determination map belongs.