Method For Producing A Workpiece By Forming Under Bending Conditions

Abstract

A method of producing a workpiece by bending a panel in a bending press, in particular an edge bending press, with measures for compensating deformations of the edge bending press due to load. The measures involve detecting the displacement forces of drive means whilst the panel is being bent at a bending depth of the bending tools that is slightly shorter than a bending depth needed to produce a predefined bending angle. From the detected displacement forces, the bending deformation of the press beams corresponding to them are determined and the displacement force of the drive means is reduced, after which a compensating device is displaced in order to set a complementary camber in support surfaces for the bending tools or tool holders, and the panel is finally bent by displacing the press beam to the bending depth corresponding to the predefined bending angle.

1 . Method of producing a workpiece by bending a panel in a bending press, with a machine frame comprising two side walls spaced at a distance apart from one another and connected to a table beam equipped with a first bending tool and a press beam equipped with another bending tool which can be displaced in guides relative to the table beam, and having drive means of a drive system for the press beam and a control and/or regulating unit with a computer and data memory, and detection means hardwired to the control and/or regulating unit, and a compensating device for creating a complementary camber in oppositely lying support surfaces of the table and press beams for the bending tools or tool holders to counter a bending deformation of the table and press beams which occurs under load due to displacement forces of the drive means, wherein once the panel has been positioned between the mutually spaced first and second bending tools, the bending tools are positioned by displacing the press beam at a bending depth slightly shorter than a bending depth needed to produce a predefined bending angle and to this end the displacement force of each drive means is derived from a measurement value of the detection means in the computer, after which the bending deformation of the table and press beams, corresponding to the displacement forces is determined as a function of machine data stored in the computer or from data stored in the data memory and the displacement force of the drive means is reduced, after which the complementary camber of the support surfaces is set by displacing the compensating device and then the panel is actually bent by displacing the press beam by the bending depth corresponding to the predefined bending angle.  
   
   
       2 . Method as claimed in  claim 1 , wherein the bending deformation of the table beam and/or the press beam is derived from the detected displacement forces and the production data for bending the panel and the machine data.  
   
   
       3 . Method as claimed in  claim 1 , wherein the displacement forces for each drive means are determined whilst the panel is being bent on the basis of the pressure level in a pressurising medium applied to the drive means.  
   
   
       4 . Method as claimed in  claim 1 , wherein the displacement forces for each drive means are determined whilst the panel is being bent on the basis of the output power of a drive of the drive means.  
   
   
       5 . Method as claimed in  claim 1 , wherein a position of the bending tools by reference to a length of the table beam and/or the press beams is determined on the basis of the displacement force of each drive means.  
   
   
       6 . Method as claimed in  claim 1 , wherein the bending deformation of at least one of the table beam and press beam and/or the flexing of the side walls is stored in a data matrix in the data memory for a predefined number of load situations.  
   
   
       7 . Method as claimed in  claim 6 , wherein once the displacement forces have been determined on the basis of a stored load situation approximately corresponding to the current one, associated setting values for the compensating device are retrieved and the compensating device is adjusted in accordance with the setting values.  
   
   
       8 . Method as claimed in  claim 1 , wherein a characteristic value in the data matrix is assigned to each load situation for setting up the compensating device.  
   
   
       9 . Method as claimed in  claim 8 , wherein the characteristic value is displayed at the control and/or regulating unit.  
   
   
       10 . Method as claimed in  claim 8 , wherein a specific setting is assigned to the characteristic value at the compensating device.  
   
   
       11 . Method as claimed in  claim 1 , wherein the bending deformation of at least one of the table beam and press beam is derived by a computing operation of the computer from the detected displacement forces of the drive means as well as the position of the bending tools and the bending length and the machine data.  
   
   
       12 . Method as claimed in  claim 1 , wherein a characteristic value is assigned to respective predefined ranges of the bending deformation.  
   
   
       13 . Method as claimed in  claim 12 , wherein control signals are generated from the characteristic value in the control and regulating unit, and displacement drives of the compensating device are activated in order to set up the compensating device on the basis of the characteristic values.  
   
   
       14 . Method as claimed in  claim 12 , wherein the compensating device is set in stages predefined by the characteristic values.  
   
   
       15 . Method as claimed in  claim 1 , wherein the compensating device is set steplessly.