Shear surface control in blanking by adaptronic systems

Due to the increasing demand of improved geometrical accuracy and reduction of the scattering of mechanical properties in finished products, the need to enhance the active control of dynamic phenomena has become more and more important in the optimization of the blanking processes. The response of the frame to the oscillations arising is strictly dependent on the characteristics of the shock damping systems used and affects the finished shear surface of manufactured parts. In this paper, the application of innovative adaptronic damping systems and the evaluation of their performances are investigated. The developed devices, based on magneto-rheological fluids, allow controllable and reversible changes of damping characteristics during cutting process when an external magnetic field is applied. The experiments, conducted on a hydraulic press using both commercially available hydraulic dampers and magneto-rheological dampers, are presented with particular focus on the excited frequencies and the vibrations to quantify the impact of dynamic phenomena on the quality of final parts. Micro-hardness tests and metallurgical observations were performed to evaluate the quality of shearing surfaces, as well as to correlate the performances of adaptronic devices to the characteristics of the sheared surfaces.