Investigation of the Equi-Potential Line Method vs. Backward Tracing Method in Preform Shape Design in Tube Hydroforming Process

A carefully selected preform process can contribute significantly to improving product quality, reducing tooling cost and processing time. Hence, it is necessary to produce a proper preform shape for the successful hydroforming from the tubular blank to final shape. In this paper, a novel method based on the equi-potential line designed in the electrostatic field was used to find an appropriate pre-form shape. The equi-potential line generated between two conductors of different voltages shows similar trends for minimum work path between the undeformed and the deformed shapes. Based on this similarity, the equi-potential line obtained by arrangement of the initial and final shapes was utilized for the design of the pre-form. Then the effectiveness of this method was compared with backward tracing method. It was shown that the new method was simpler and more accurate than the backward tracing method in finding the pre-form shape. As a result, this approach can be extended to a wide range of practical tube hydroforming processes.

Keywords:

Tube hydroforming , Preform shape , Backward Tracing , Equi-Potential Line