Model-based control of strip bending in mass production

The bending angle in an industrial strip bending process for mass production is influenced by uncontrollable process and material variations like thickness, strength and friction. Most of these variations are not directly measurable in the production line. In a two stage bending operation, the force-time curve of the pre-bending step is measured and used to adapt the back-bending displacement. In this study several measurements from long test runs are evaluated and the feasibility of model-based control in metal forming is discussed. It is concluded that a model-based control scheme is required to reach an angular accuracy of 0.1°.