盒形件分区变压边力拉深研究

Research on box-drawing based on variable blank-holder force

以盒形件为研究对象,根据盒形件受力情况将压边圈分区为圆角部分和直边部分。基于有限元模拟软件DYNAFORM,对盒形件进行拉深模拟分析,建立了评判成形质量的目标函数,采用正交试验的方法对变压边力拉深进行了研究。正交试验以拉深成形过程的5个位置:0,10,20,25和30 mm所对应的压边力值作为5个因素,进行五因素四水平的正交试验。与恒压边力加载的拉深相比,通过正交试验优化得到的"形"变压边力曲线进行数值模拟后,获得的综合指标为5.170,小于恒压边力加载模式的最小指标5.465,显著改善了盒形件的成形质量。试验验证的结果表明,随位置和行程变化的分区变压边力能有效控制起皱和拉裂等缺陷,从而提高盒形件的成形质量。

For the rectangular box, the blank-holder was segmented into the comer area and the straight side area based on the forces acting on it. The forming process of rectangular box was analyzed by DYNAFORM, and the objective function was established to evaluate the forming quality. Furthermore, the drawing process with variable blank-holder force was studied by orthogonal test. The five different positions O, 10, 20, 25 and 30 mm were selected in the drawing process, their BHF values were regarded as five factors of orthogonal test. The five-factor and four-level orthogonal test was carried out. The comprehensive index 5. 170 is obtained by simulation on the blank-hold- er force curve optimized from orthogonal test, which is less than the minimum value 5.465 produced by constant BHF mode. The results of experiments show that partition VBHF changing with the position and process can effectively prevent the occurrence of wrinkling and fracture, and the forming quality of stainless steel rectangular box can be ensured.