A Hybrid Flexible Sheet Forming Approach towards Uniform Thickness Distribution

This paper presents a newly developed flexible sheet forming approach with better sheet thickness distribution and reduced processing time comparing to the conventional incremental sheet forming. In the approach, a two-step forming process has been proposed: multi-point forming as preforming is employed to achieve an initial shape and designed thickness distribution; After the preforming, incremental sheet forming process is then applied to finalize part geometry with desired thickness distribution. In the work, a numerical model for predicting the thickness distribution of the final part is developed by integrating finite element simulation and analytical prediction of ISF process. To achieve the uniformity of final thickness distribution, the preformed shape is optimized based on the developed thickness prediction model. Additionally, a real industrial case problem of forming an aerospace cowling is used to validate the proposed hybrid flexible sheet forming approach. Satisfactory results are obtained, which demonstrates the feasibility and effectiveness of the developed forming process.