Investigation on the precision cropping system with high-speed and centrifugal action

In view of the special shape of V-shaped notch on metal bar in course of low-stress bending blanking, a new-type of cropping method, which is a precision cropping system with high-speed and centrifugal action, is proposed by introducing the crack controlled expansion and the centrifugal technology into the low-stress blanking. The working principle of the cropping method is introduced, and the calculation method of critical initial loading force acted on the metal bar is given. By means of ADAMS software, the movement characteristic of the slide block is obtained. Based on the characteristic of low-stress blanking, five types of excited frequency control curves are designed and applied in the cropping experiments and influences of these control curves on the cropping cross-section quality and the cropping time are analyzed in detail. The cropping experimental results show that 1/2 cosine decrease control curve, by which the high-quality cross section is obtained and the cropping time is reduced to 3 s, is an ideal control mode compared with other control modes mentioned in this paper. Finally, influence of geometric parameters of V-shaped notch on the cropping time is analyzed and the ideal combination of geometric parameters of V-shaped notch is also determined.