Method for deep-drawing blanks, in particular deep-drawn sheets for motor-vehicle body elements

摘要

The invention relates to a method for deep-drawing blanks, in particular deep-drawn sheets for motor-vehicle body elements. In this method, a hydraulic deep-drawing press (2) is used in which the blank (5), during the deformation process brought about by an upper die (6) of a press ram (10) cooperating with a lower die (4), is firmly clamped at its edge regions between a sheet-holder body (7) of a sheet holder (8) and a die cushion (11), and the sheet-holder pressure is applied by valve-controlled sheet-holder cylinders (9.1-9.4) which, in addition, determine the movement sequence of the sheet holder (8). In order to enable the quality of the deep-drawn parts produced in such deep-drawing presses (2) to be optimised and, moreover, to achieve rapid and simple adaptation of the deep-drawing press (2) to the production of deep-drawn parts to be formed and shaped differently, provision is made for the valves (16.1-16.4 and 20.1-20.4 and 24.1-24.4) arranged upstream of the respective sheet-holder cylinders (9.1-9.4) to be supplied by an electronic control system (14) with switching signals which alter the cylinder pressure of the sheet-holder cylinders (9.1-9.4) a number of times during the deformation process. The drawing-path-dependent sheet-holder pressure then corresponds to a specified curve (49) desired for each deep-drawn part to be produced. IMAGE