Electromagnetic-assisted calibration for surface part of aluminum alloy with a dedicated uniform pressure coil

Springback is an inevitable defect of aluminum alloy sheet after conventional stamping process, which directly has an influence on the forming accuracy of part. For a surface part of aluminum alloy, the stamping process was used to complete the preforming process, and then the electromagnetic forming was adopted to calibrate the shape and improve the forming accuracy. A dedicated uniform pressure coil was proposed to quasi-uniformly impose the impulse magnetic pressure on the whole part. The effect of discharge voltage on the springback phenomenon was experimentally and numerically investigated. It was found that the springback defect of surface part was significantly reduced with the discharge voltage increasing. The forming accuracy of surface part was remarkably improved under the discharge voltage of 5 kV. It can be attributed to two aspects: on the one hand, the effective plastic strain level at the bottom of surface part was greatly elevated, and on the other hand, the gap between the tensile stress on the exterior surface and the compressive stress on the interior surface was well decreased.