A binding scheme to minimize thinning of formed tailor welded blanks

Seyam, M. S., M. Shazly, A. El-Mokadem, and A. S. Wifi, A binding scheme to minimize thinning of formed tailor welded blanks, , 2018.


Weld line movements (WLM) and thinning in draw bending and deep drawing of Tailor Welded Blanks (TWBs) constitute major defects in automotive applications. The present work aims at the development of a binding scheme that improves sheet thinning and eliminates WLM. This is achieved by using controlled blank holding segmented binders (blank holders) at the boundaries of the parent sheets of the TWB and counter pins at the weld lines. Analytical models for the 2-D draw bending and 3-D deep drawing are developed to predict the required blank-holder/counter-pin forces that insures identical elongation (deformation) on both sides of the TWB and thus eliminates the WLM. The 2-D model is validated by a series of draw-bending laboratory experiments. The experimentation of the proposed force scheme produced identical elongations on both parent sheets and consequently zero weld line movement (WLM) as targeted by the analytical model and hence the feasibility of the proposed scheme is proved in practice. Additional draw-bending/box-drawing experiments are conducted to compare the proposed scheme with separate use of either segmented blank holders, weld line clamping pins or counter punch. The results showed improved reduction in thinning and elimination of WLM when the binding forces of the process are controlled as proposed by the developed model.



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