Method for the production of sheet metal parts and device therefor

Abstract

The invention relates to a method and to a device for producing sheet metal components with substantially reduced springback.

1 . A method for producing a sheet metal component, wherein the method comprises at least two steps:
 preforming a metal sheet to give a sheet metal preform having, in cross section (Q), a base, at least one body, at least one transition between the base and the body, at least in some region or regions, a flange, and at least in some region or regions, a transition between the body and the flange in a preforming tool, which acts by means of its effective surfaces on the metal sheet, wherein the sheet metal preform has excess sheet metal material, at least in some region or regions; and   final forming of the sheet metal preform to give a sheet metal component in a sizing tool, which acts by means of its effective surfaces on the sheet metal preform, and in which the excess sheet metal material is compressed in the sheet plane (E);   wherein the effective surfaces of the preforming tool of the sheet metal preform to be produced are configured in such a way in comparison with the effective surfaces of the sizing tool of the sheet metal component to be produced that, at least on of (i) when the preforming tool and the sizing tool are compared, a torsion angle difference (tdiff) of at least 0.2° is established on consideration of the differential angle between the two main axes of inertia—said axes being oriented the same way with respect to the respective cross-sectional shape—through the centroids of two parallel cross-sectional areas, 100 mm apart, of the tool gap enclosed by the respective effective surfaces; and   (ii) that a curvature in the longitudinal extent of the sheet metal preform that deviates by at least 1% from the curvature in the longitudinal extent of the sheet metal component to be produced is established at least in some region or regions in the sheet metal preform to be produced in comparison with the sheet metal component to be produced.   
     
     
         2 . The method as claimed in  claim 1 , wherein the effective surfaces of the preforming tool are configured in such a way in comparison with the effective surfaces of the sizing tool that a body opening angle difference (zdiff) of at least 0.5° is established at the same location in the sheet metal preform to be produced in comparison with the sheet metal component to be produced. 
     
     
         3 . The method as claimed in  claim 2 , wherein a steel sheet with a yield strength Re of at least 400 MPa is used. 
     
     
         4 . A device for producing a sheet metal component, for carrying out a method as claimed in  claim 3 , having at least one preforming tool for preforming a metal sheet to give a sheet metal preform having, in cross section, a base, at least one body, at least one transition between the base and the body, at least in some region or regions, a flange, and, at least in some region or regions, a transition between the body and the flange, which preforming tool acts by means of its effective surfaces on the metal sheet, wherein the sheet metal preform has excess sheet metal material, at least in some region or regions; and having at least one sizing tool for compressing the sheet metal preform to give a fully formed sheet metal component, which sizing tool acts by means of its effective surfaces on the sheet metal preform, and in which the excess sheet metal material is compressed in the sheet plane; wherein the effective surfaces of the preforming tool of the sheet metal preform to be produced are configured in such a way in comparison with the effective surfaces of the sizing tool of the sheet metal component to be produced that, at least one of (i) when the preforming tool and the sizing tool are compared, a torsion angle difference (tdiff) of at least 0.2° is established on consideration of the differential angle between the two main axes of inertia—said axes being oriented the same way with respect to the respective cross-sectional shape—through the centroids of two parallel cross-sectional areas, 100 mm apart, of the tool gap enclosed by the respective effective surfaces; and (ii) that a curvature in the longitudinal extent of the sheet metal preform that deviates by at least 1% from the curvature in the longitudinal extent of the sheet metal component to be produced is established at least in some region or regions in the sheet metal preform to be produced in comparison with the sheet metal component to be produced. 
     
     
         5 . The device as claimed in  claim 4 , wherein the effective surfaces of the preforming tool are configured in such a way in comparison with the effective surfaces of the sizing tool that a body opening angle difference of at least 0.5° is established at the same location in the sheet metal preform to be produced in comparison with the sheet metal component to be produced. 
     
     
         6 . The device as claimed in  claim 5 , wherein the sizing tool has a sizing punch, a sizing die and at least one element of, wherein the element is arranged in the sizing die and can be moved relative to the sizing die. 
     
     
         7 . The device as claimed in  claim 6 , wherein the sizing punch is arranged at the bottom and the sizing die at the top in the sizing tool. 
     
     
         8 . The device as claimed in  claim 5 , wherein the sizing tool has a sizing punch, a sizing die and at least one element of, wherein the at least one element is arranged in the sizing punch and can be moved relative to the sizing punch. 
     
     
         9 . The device as claimed in  claim 8 , wherein the sizing punch is arranged at the top and the sizing die at the bottom in the sizing tool. 
     
     
         10 . The device as claimed in  claim 6 , wherein the at least one element arranged in the sizing die is moved in a controlled manner by at least one of means of the ram stroke and additional control units in such a way that a defined distance is obtained between the element and the sizing punch during the closure of the sizing tool. 
     
     
         11 . The device as claimed in  claim 10 , wherein the at least one element ends substantially flush with the effective surface of the sizing die during closure, before the lower end position is reached. 
     
     
         12 . The device as claimed in  claim 8 , wherein the at least one element arranged in the sizing punch is moved in a controlled manner by at least one of means of the ram stroke and additional control units in such a way that a defined distance is obtained between the element and the sizing die during the closure of the sizing tool. 
     
     
         13 . The device as claimed in  claim 12 , wherein the element ends substantially flush with the effective surface of the sizing die during closure, before the lower end position is reached. 
     
     
         14 . The device as claimed in  claim 13 , wherein the device is integrated in one of a press line, transfer press and compound progressive press.