Experimental investigations on the forming mechanism of a new incremental stretch-flanging strategy with a featured tool

摘要

In conventional stretch-flanging process by incremental sheet forming (ISF), serious thinning is a major challenge due to the ISF deformation mechanism of stretching, bending, and considerable shearing in the area far from the flange edge. To solve this problem, a new flanging tool for ISF is proposed, accompanied with the suitable tool path strategy. In order to obtain a better understanding of this new stretch-flanging approach, experiments have been conducted to study the geometric accuracy, thickness distribution, forming force, and fracture behavior of typical circle and square flange features. Besides, the effect of tool radius on the new stretch-flanging process is also investigated. Results show that the forming strategy which the tool moves horizontally in the X-Y plane is the most suitable one for the new flanging tool. Thicker but shorter flange with a more uniform thickness distribution can be obtained by the proposed stretch-flanging approach. Tool radius also has an important influence on the diameter of the final hole, the forming depth, and the fracture limit strains in the new stretch-flanging process.