Deep drawing with radial segmental blank holder based on magnetic control

Abstract

<p indent=0mm>We propose a radial segmental blank holder technique based on the electro-permanent magnet (EPM) technology, in which we can obtain a more reasonable blank holding force (BHF). The magnetic pole unit was constructed according to the characteristics of soft magnetic materials and adjusted the magnetic state of the magnetic pole unit by an instantaneous low-intensity current. The tensile test revealed that the magnetic pole unit can provide a sufficiently large magnetic attraction force to satisfy the blank holding requirements. The measurement results of the temperature rise experiment verified that the magnetic pole unit would not cause overheating. According to the characteristics of the drawing process, the blank holder device and the drawing die based on EPM technology were designed. The BHF applied during the drawing process does not need to be continuously energized, so it has the advantages of energy-saving and safety. Theoretical derivation was used to determine the feasibility of the radial segmental blank holder technique and analyzed the initial distribution of the BHF on sheet metal using FEA. The results show that, compared with the conventional blank holder, we could implement the BHF applied by the new method in a larger radial area. We further verified the efficiency of the radial segmental blank holder technique by performing simulation. Since the BHF is more rationally distributed in the radial direction, we could control the sheet thickness variation better. Finally, the drawing experiment of the galvanized sheet revealed that the EPM technology is feasible for the blank holder, and the radial segmental blank holder technique can efficiently suppress wrinkling and enhance the performance.