板材拉深成形电控永磁压边方法研究

为了克服传统压边方法不能独立施加压边力，电磁压边能耗高且发热量大的问题，提出了一种基于电控永磁技术的压边方法。根据电控永磁技术和拉深成形工艺的特点，研制了带有磁力压边装置的拉深成形模具。采用有限元方法模拟了磁极单元和磁垫的充退磁过程，在进行磁场和力学场耦合分析的基础上，确定了以磁吸力作为压边力施加在成形板坯上的接触压力分布。由有限元软件模拟的电控永磁压边与传统压边作用下板坯的成形效果可知，两种压边方法所得拉深件的应变分布基本一致。采用电控永磁压边方法分别对直径为180 mm和195 mm的08Al板坯（厚度为0.98 mm）进行了拉深实验，拉深高度为48 mm，结果表明，电控永磁压边方法可以实现压边力的独立加载，能够提供足够大的压边力。最后，分别计算了采用传统压边方法、电磁压边方法和电控永磁压边方法的能量消耗，其中，电控永磁压边方法节能效果最好，相对于电磁压边方法，节能高达95%以上。

Research on Deep Drawing of Sheet Metal Using EPM Blank Holder Technique

 In order to overcome the problems that the conventional blank holder could not apply BHF independently, and the overheating problem of electromagnetic blank holders, a novel blank holder technique was proposed based on EPM technology.  According to the characteristics of EPM technology and deep drawing processes, a deep drawing die with magnetic cushion was designed and manufactured. The magnetization and demagnetization states of magnetic pole unit and the cushion were simulated by finite element analysis(FEA). Based on the coupling analysis of magnetic field and mechanics field, the distributions of contact pressures applied on the sheets by magnetic forces were determined. By using FEA, the deep drawing processes of cylindrical cups were simulated with conventional blank holder and the new technique respectively. The results show that the strain distributions of the drawn parts obtained by the two blank holder methods is basically the same. Using EPM blank holder, the drawing experiments of 08Al sheets (thickness is as 0.98 mm) with diameters of 180 mm and 195 mm were carried out, where the drawing heights were as 48 mm. The results demonstrate that the large enough BHF may be applied independently using the new EPM blank holder method. Finally, the energy consumption of the conventional blank holder, the electromagnetic blank holder and the EPM blank holder method were calculated respectively. Among them, the EPM blank holder method has the best energy saving effectiveness. Compared with the electromagnetic blank holder, the energy saving rate using the new blank holder method is as high as 95%.