Stretch forming system and stretch forming method

Abstract

A stretch forming system has jaws clamping a workpiece at end edge portions, a die disposed between the jaws and coming into contact with the workpiece, and a plurality of control axes changing relative positions and orientations of the jaws with respect to the die, and has a jaw path calculating unit calculating paths of the relative positions and orientations of the jaws with respect to the die when the workpiece is wrapped onto the die by moving the die in a vertical direction under a restricting condition that the positions and orientations of the jaws are freely changeable except for movement in a vertical direction being regulated, and a control axis operation pattern calculating unit calculating operation patterns of the plurality of the control axes achieving the paths of the jaws.

1 . A stretch forming system comprising:
 first and second jaws clamping a workpiece at respective end edge portions opposite to each other;   a die disposed between the first and second jaws and coming into contact with the workpiece; and   a plurality of control axes changing relative positions and orientations of the first and second jaws with respect to the die;   a jaw path calculating unit calculating respective paths of the relative positions and orientations of the first and second jaws with respect to the die when the workpiece is wrapped onto the die by moving the die in a vertical direction under a restricting condition that respective positions and orientations of the first and second jaws are freely changeable except for movement in a vertical direction being regulated; and   a control axis operation pattern calculating unit calculating respective operation patterns of the plurality of the control axes achieving the respective paths of the relative positions and orientations of the first and second jaws with respect to the die calculated by the jaw path calculating unit.   
     
     
         2 . A stretch forming system comprising:
 first and second jaws clamping a workpiece at respective end edge portions opposite to each other;   a die disposed between the first and second jaws and coming into contact with the workpiece; and   a plurality of control axes changing relative positions and orientations of the first and second jaws with respect to the die;   a jaw path calculating unit calculating respective paths of the relative positions and orientations of the first and second jaws with respect to the die when the workpiece is wrapped onto the die by moving the die in a vertical direction under a restricting condition that respective positions and orientations of the first and second jaws are freely changeable except for movement in a vertical direction being regulated and rotation around a rotation center line being regulated, the rotation center line extending in a direction that is a horizontal direction orthogonal to a jaw facing direction; and   a control axis operation pattern calculating unit calculating respective operation patterns of the plurality of the control axes achieving the respective paths of the relative positions and orientations of the first and second jaws with respect to the die calculated by the jaw path calculating unit.   
     
     
         3 . The stretch forming system according to  claim 1 , wherein the jaw path calculating unit calculates the respective paths of the relative positions and orientations of the first and second jaws with respect to the die by using a workpiece having a thickness thinner than the thickness of the actual workpiece. 
     
     
         4 . The stretch forming system according to  claim 1 , further comprising a die movement amount calculating unit calculating first and second intersections between the respective paths of the relative positions of the first and second jaws with respect to the die calculated by the jaw path calculating unit and respective tangent lines at the both end edge portions of a forming surface of the die,
 the die movement amount calculating unit calculating first and second vertical direction distances from the calculated first and second respective intersections to an apex of the die,   the die movement amount calculating unit comparing the calculated first and second vertical direction distances with each other to determine the greater one as a relative vertical-direction movement amount of the die with respect to the first and second jaws.   
     
     
         5 . A stretch forming method of using first and second jaws clamping a workpiece at respective end edge portions opposite to each other, a die disposed between the first and second jaws and coming into contact with the workpiece, and a plurality of control axes changing relative positions and orientations of the first and second jaws with respect to the die to wrap the workpiece onto the die by the first and second jaws for forming, the method including
 calculating respective paths of the relative positions and orientations of the first and second jaws with respect to the die when the workpiece is wrapped onto the die by moving the die in a vertical direction under a restricting condition that the respective positions and orientations of the first and second jaws are freely changeable except for movement in a vertical direction being regulated, and   calculating respective operation patterns of the plurality of the control axes achieving the calculated respective paths of the relative positions and orientations of the first and second jaws with respect to the die.   
     
     
         6 . A stretch forming method of using first and second jaws clamping a workpiece at respective end edge portions opposite to each other, a die disposed between the first and second jaws and coming into contact with the workpiece, and a plurality of control axes changing relative positions and orientations of the first and second jaws with respect to the die to wrap the workpiece onto the die by the first and second jaws for forming, the method including
 calculating respective paths of the relative positions and orientations of the first and second jaws with respect to the die when the workpiece is wrapped onto the die by moving the die in a vertical direction under a restricting condition that the respective positions and orientations of the first and second jaws are freely changeable except for movement in a vertical direction being regulated and rotation around a rotation center line being regulated, the rotation center line extending in a direction that is a horizontal direction orthogonal to a jaw facing direction, and   calculating respective operation patterns of the plurality of the control axes achieving the calculated respective paths of the relative positions and orientations of the first and second jaws with respect to the die.   
     
     
         7 . The stretch forming system according to  claim 2 , wherein the jaw path calculating unit calculates the respective paths of the relative positions and orientations of the first and second jaws with respect to the die by using a workpiece having a thickness thinner than the thickness of the actual workpiece. 
     
     
         8 . The stretch forming system according to  claim 2 , further comprising a die movement amount calculating unit calculating first and second intersections between the respective paths of the relative positions of the first and second jaws with respect to the die calculated by the jaw path calculating unit and respective tangent lines at the both end edge portions of a forming surface of the die,
 the die movement amount calculating unit calculating first and second vertical direction distances from the calculated first and second respective intersections to an apex of the die,   the die movement amount calculating unit comparing the calculated first and second vertical direction distances with each other to determine the greater one as a relative vertical-direction movement amount of the die with respect to the first and second jaws.