圆锥形凹模径向分块压边拉深工艺实验研究

采用圆锥形凹模拉深工艺可以提高成形极限，但需要用压边圈将板坯先压成与凹模面吻合的形状，当变形程度较大时，板坯很容易起皱。为了克服这一缺点，提出了将圆锥形凹模与径向分块压边方法结合的工艺，该工艺可有效改善压边圈与板坯的约束状态,从而达到抑制起皱的目的。对圆筒形件的拉深成形，采用了刚柔复合的径向分块压边圈结构，设计了圆锥形凹模径向分块多压边圈拉深模，取不同凹模半锥角的圆锥形凹模进行了圆筒形件的拉深成形实验。实验表明,新的压边方法能有效克服初始成形过程的起皱，可与锥度较小的凹模一起使用。采用凹模半锥角为45°的凹模,得到AA5754、AA6061和08Al三种板材的极限拉深系数分别为0.410、0.431、0.373，显著提高了成形极限。对圆锥形凹模的拉深成形，给出了理论计算成形极限的方法，理论与实验结果非常接近。

Experimental Research on Deep Drawing Process Using Radial Segmental Blank Holders with Conical Die

The forming limit  could be improved by using the conical die in the deep drawing process when the blank  was drawn to the shape accordant to the inside surface of the die.And the blank wrinkled  easily  during the large deformation process.A  new technology combining  the conical die with  the radial segmental blank holding technique was proposed  to  improve the restrain conditions  between the blank holders  and the blank and to suppress the wrinkles.The drawing  die were designed with the conical die and the rigid-flexible composite segmental blank holders and the experiments for the cylindrical cup deep drawing process were  conducted using the conical dies with different die semi-cone  angles.The  results reveal that the wrinkles at the beginning of the drawing process can be  overcame  effectively by the new blank holding method with smaller conical angles. The forming limit  coefficients for AA5754, AA6061 and 08AL are  as 0.410,0.431 and 0.373 respectively, which are enhanced effectively, adopting the die with 45° die  semi-cone angle.The theoretical forming limit  calculation method for the deep drawing process with the conical die is given and the theoretical results are accordant with the experimental ones.