Closed-loop control of the blank-holder force in deep-drawing: finite-element modeling of its effects and advantages

As a steelmaker specialized in the manufacturing of flat coated sheets, the authors' company started some research into the stamping domain with a special focus on the influence of friction, on material modeling and on the improvement of drawing performances. The main purpose in doing such research is to enhance the company's knowledge in the final use of its products and to know how to orientate that use.

Therefore, from a technological point of view, the company developed a completely new (and patented) regulation system to control the blank-holder pressure. In this system, working in closed-loop, the feedback-loop controlling the variation of the blank-holder pressure can be based on several process parameters such as the punch force or the detection of the occurrence of wrinkling.

From a numerical point of view, the effects and the impacts of this new system have been simulated, in the cases of both potential laboratory and industrial applications. Those simulations were performed with a commercial finite-element code using an explicit integration scheme, and are mainly related to the following applications: (i) the minimum blank-holder pressure needed to avoid the occurrence of wrinkling; and (ii) the improvement of drawing performance through the increase of the LDR value, this being done by maximizing the blank-holder pressure.