Study on subsection variable blank holder force in deep drawing of rectangular parts

Abstract

To load blank holder force (BHF) in deep drawing of non‐axisymmetric parts, theoretical calculation models of radial pull‐stress on different sbsection flanges of rectangular parts were built up separately, based on analysis of plastic mechanics. Numerical simulations were carried out to verify the validity of the models. To verify the possibility of optimising loaded subsection U mode of variable BHF curves by numerical simulation, experiments were carried out on hot‐galvanised steel sheets for automobiles using an innovative structure of dual layers of binders and a novel probe ensor, and the guidelines were chosen as the mean square deviation of the thinning ratio of sheet thickness in numerical simulations and thickness measurements in tests. Final results showed that subsection U mode of variable BHF control can be more effective to reduce the thinning ratio of sheet thickness on the dangerous sidewall of final parts.

Keywords:

• Deep drawing
• BHF
• Rectangular part
• Subsection holders
• Dual layers of holders

This work was sponsored by Priority Themes of Major Projects in Zhejiang Province (No. 2008C01059‐1), and Science and Technology Projects of Zhejiang Province (No. 2006C21042), Science and Technology Project of the Education of Zhejiang Province (No. Y200908117).