Development of forming process for deep drawing of square cup with optimized blankholder pressure

Abstract A novel segmental blank holder technique was developed to apply BHF on sheet metal, in which the binder was divided into double rings to apply blank holding force (BHF) independently and effectively on different flange regions. Firstly, the holding principles were expatiated by theoretical derivation. The results show that the BHF can be applied on different radial areas independently. Then The reasonable of segmental blank holder technique was proven by forming simulation. the distribution of BHF applied by the new blank holder is reasonable than that of single blank holder. Finally, the feasibility of the segmental blank holder technique was proven by a series of experiments. the flange wrinkling was demonstrated to be more eliminated than that using the single blank holder. Also, the result indicates that compared with 1:2 and 2:1, when the distribution ratio between outer ring and the inner ring is 1:2, there have a better forming quality.