A novel multi-DOF point envelope forming process for manufacturing thin-walled components

Abstract

Thin-walled components are widely used in aerospace, ship and automotive industries owing to the light weight advantages. Rotary forging is an advanced process for manufacturing thin-walled components owing to its local deformation mode and small forming force. However, for large scale thin-walled components, the forming force in rotary forging becomes larger because of the larger contacting area between dies and thin-walled component (The contact between dies and thin-walled component is line contact in theory). Therefore, it is necessary to further reduce the forming force in rotary forging so as to improve its process limits. This paper proposes a novel multi-DOF point envelope forming process for manufacturing thin-walled components, in which the contacting area between dies and thin-walled component is significantly reduced and consequently the forming force is significantly reduced (The contact between dies and thin-walled component is point contact in theory). Firstly, the principle of multi-DOF point envelope forming process is proposed. Secondly, the design methods for envelope die geometry and motion are developed. Thirdly, a FE model for multi-DOF point envelope forming process of a thin-walled component is established. Through the FE simulation, the evolution laws of plastic strain, metal flow velocity, geometry shape and forming force are revealed. Finally, a novel multi-DOF envelope forming equipment is developed and the multi-DOF point envelope forming experiment of a thin-walled component is carried out. The simulation and experimental results indicate that the proposed multi-DOF point envelope forming process and equipment are suitable for manufacturing thin-walled components and the forming force can be significantly reduced compared with rotary forging.