Precision forming of thin-walled hollow components with the complex surface by self-adaptive non-uniform pressure

Abstract

The precision forming of thin-walled hollow components with the complex surface is difficult due to the excessive thinning of small radius circular arcs and the springback of small curvature surfaces. The difficulty is because the pressure required for forming a small radius circular arc is larger than that needed for other regions, while the pressure supplied inside the hollow blank in a conventional hydroforming process is equal everywhere causing the forming pressure cannot meet the requirements of different deformation regions. To solve this problem, the thin-walled hollow component with the complex surface is formed precisely by employing self-adaptive non-uniform pressure. Herein, theoretical analysis of the self-adaptive non-uniform pressure of viscous medium acting on the blank and the stress distribution of blank during the circular arc filling process is conducted. Then, different viscous medium parameters are employed in the forming of hollow components with different circular arc radii by numerical simulation. The results indicate that the non-uniform pressure is formed during the forming process, and is affected by the mechanical properties of viscous medium. The stress and strain distribution of blank are uniform, as well as the wall thickness thinning ratio and springback are small when the appropriate viscous medium is selected. As an application, the thin-walled hollow turbine blade is manufactured. The wall thickness is uniform and the dimensional deviation is kept at a lower level.