Comparative analyses off the deep drawing process with extended process kinematics

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Necking and wrinkling are the main cases of failure in deep drawing processes. Different approaches have been tested so far to effectively exploit the deformability of the material. The development of high dynamic servo press technology enables the implementation of new technologies with active changes in loading during variable path of the press ram and die cushion. The well-known technology of the pulsating die cushion extends the forming limits. A more recent approach is the simultaneous pulsation of the die cushion and ram which is designated as a cushion-ram-pulsation. In preliminary investigations some effects could be shown which lead to a further extension of the forming limits. The knowledge of the stress conditions in the contact area and the forecast of the process parameters are insufficient for the cushion-ram-pulsation. Today an appropriate basis of evaluation is still lacking. For example, if the amplitudes of the load changes are in the same order as backlash and as elasticity in the whole system of tool and machine, these quality-determining factors must be taken into account in the process setup by superimposed vibrations. In the proposed project, a method for evaluating single-force-terms shall be used to allow a direct comparison between the standard deep drawing, the cushion pulsation and the new cushion-ram-pulsation and to clarify the observed phenomena of processes with variable kinematics.