Method and arrangement for changing the shape of a sheet-like workpiece

Abstract

A method for changing the shape of a sheet-like workpiece, which has a mould recess formed by reducing the thickness of the material, includes arranging the workpiece on at least two spaced-apart supporting elements of a machine bed, and forming the workpiece into a final shape by step-by-step free bending. The steps of bending a part of the workpiece by lowering an upper die between the supporting elements from a waiting position into a forming position, raising the upper die into the waiting position and moving the position of the workpiece relative to the machine bed in at least one infeed direction are performed repetitively. Before the workpiece is formed into the final shape, a filling element, which is adapted to the mould recess and designed to make up the material thickness, is produced and is arranged in the region of the mould recess. An arrangement is also provided.

1 . A method for changing the shape of a sheet-like workpiece, which has a mould recess formed by reducing the thickness of the material, comprising:
 arranging the workpiece on at least two spaced-apart supporting elements of a machine bed;   forming the workpiece into a final shape by step-by-step free bending, in that the steps of;
 bending a part of the workpiece by lowering an upper die between the supporting elements from a waiting position into a forming position; 
 raising the upper die into the waiting position; and 
 moving the position of the workpiece relative to the machine bed in at least one infeed direction; 
   are performed repetitively;   wherein before the workpiece is formed into the final shape, a filling element, which is adapted to the mould recess and designed to make up the material thickness, is produced and is arranged in the region of the mould recess.   
     
     
         2 . The method according to  claim 1 , wherein the filling element is produced at least substantially as a negative form of the mould recess. 
     
     
         3 . The method according to  claim 1 , wherein, in regions of the mould recess with reduced material thickness, the filling element has a minimum thickness in each case which corresponds at least to an amount of reduction in the material thickness of the workpiece in this region. 
     
     
         4 . The method according to  claim 1 , wherein the filling element is produced in such a manner that, when arranged in the mould recess, it finishes flush with an upper side of the workpiece, forming an at least substantially smooth pressure surface. 
     
     
         5 . The method according to  claim 4 , wherein the filling element is produced so as to protrude with respect to the pressure surface in predetermined raised regions. 
     
     
         6 . The method according to  claim 5 , wherein a pressure-resistant foil is arranged on the pressure surface of the filling element for producing the raised regions. 
     
     
         7 . The method according to  claim 6 , wherein the foil is glued on. 
     
     
         8 . The method according to  claim 1 , wherein the filling element is made of acrylonitrile butadiene styrene (ABS). 
     
     
         9 . The method according to  claim 1 , wherein the filling element is produced by machining. 
     
     
         10 . The method according to  claim 1 , further comprising arranging a resilient supporting surface element between the supporting elements of the machine bed and the workpiece. 
     
     
         11 . An arrangement for changing the shape of a sheet-like workpiece, which has a mould recess formed by reducing the thickness of the material, comprising:
 at least two spaced-apart supporting elements designed for arranging the workpiece on the machine bed;   a forming device designed for forming the workpiece into a final shape by step-by-step, repetitive free bending with an upper die, the upper die being controllably lowerable from a waiting position into a forming position for bending a part of the workpiece;   positioning means configured for moving a position of the workpiece relative to the machine bed in at least one infeed direction; and   a filling element adapted to the mould recess and configured to make up the material thickness, the filling element configured to be arranged in a region of the mould recess before the workpiece is formed into the final shape.   
     
     
         12 . The arrangement according to  claim 11 , wherein the filling element is configured at least substantially as a negative form of the mould recess. 
     
     
         13 . The arrangement according to  claim 11 , wherein, in regions of the mould recess with reduced material thickness, the filling element has a minimum thickness in each case which corresponds at least to an amount of reduction in the material thickness of the workpiece in this region. 
     
     
         14 . The arrangement according to  claim 11 , wherein the filling element is configured in such a manner that, when arranged in the mould recess, it finishes flush with an upper side of the workpiece forming an at least substantially smooth pressure surface. 
     
     
         15 . The arrangement according to  claim 14 , wherein the filling element is configured so as to protrude with respect to the pressure surface in predetermined raised regions. 
     
     
         16 . The arrangement according to  claim 15 , wherein a pressure-resistant foil is arranged on the pressure surface for producing the raised regions. 
     
     
         17 . The arrangement according to  claim 16 , wherein the foil is joined to the pressure surface by means of an adhesive bond. 
     
     
         18 . The arrangement according to  claim 11 , wherein the filling element is made of acrylonitrile butadiene styrene. 
     
     
         19 . The arrangement according to  claim 11 , further comprising a resilient supporting surface element arranged between the supporting elements of the machine bed and the workpiece.