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The electromagnetic blank holder is an advanced technology for sheet metal drawing using electromagnetic force. This paper introduces the electromagnetic blank holder and its working principle. The calculations of theoretical electromagnetic force, excitation current and maximum coil turns of electromagnetic blank holder system are given. The simulation model of the electromagnetic blank holder system is established using Maxwell software. The static magnetic field simulation of the electromagnetic blank holder is carried out according to the varied size of the plate and varied exciting current of the coil. The magnetic field distribution of the blank holder and magnetic ring is shown. The magnitude values of the electromagnetic force exerted on plate, blank holder and magnetic ring is given. The research results of this paper have important theoretical help for realizing the electromagnetic blank holder of sheet metal drawing in production practice.

In this study, an intelligent strategy of predicting the maximum thinning rate is proposed. Prediction strategy is based on Back Propagation Neural Network (BPNN). Because Blank Holder Force (BHF) can effectively reflect the thinning rate of cylindrical part with flange, the nodes of which are served as the inputs of BPNN in this research. The prediction objective is to obtain corresponding the maximum thinning rate of cylindrical part, which is served as the output of BPNN. The inputs data are derived from designed several critical types of Variable Blank Holder Force (VBHF). In addition, the output data is originated from corresponding simulation results of cylindrical part drawing. The mathematical expressions of prediction process have also been given in this paper. The advantage of this novel prediction strategy is that it can rapidly and accurately obtain the thickness reduction rate of cylindrical part with flange. Eventually, the validation of the created prediction method is proved by corresponding simulations and experiments.