Two-Level Static Floatation Tool Used in Belt Grinding for Root Fillet of Titanium Alloy Blade

Abstract

The root fillet of key components in aero-engines, such as the blade, blisk, and blade ring, is the most stress-concentrated area during thermodynamic interactions. The root fillet is constructed with a small curvature radius and variable curvature in different sections. Variable curvature is difficult to achieve with the integrated heat in the grinding process, and the surface quality of the root fillet is therefore greatly influenced. A “horseshoe nest”may be created in the high-temperature air environment, which would significantly affect the fatigue life of the key components. Therefore, to solve the problem of precision grinding for a variable-curvature root fillet, a two-level static floatation tool is proposed for belt grinding. First, the system design of the two-level static floatation tool is introduced, and the principle of the two-level static air floating is analyzed based on fluid dynamics. Second, the deformation and stress distribution of the two-level static floatation tool is analyzed when combined with the belt grinding process for a variable-curvature root fillet. Finally, an experiment performed on the root fillet of an aero-engine titanium alloy blade is described. The results show that the surface roughness is less than 0.4 μm, the profile precision errors are less than 5%, the transition is smooth between the plane and the fillet (blade surface to root fillet rabbet), and a longitudinal texture on the blade root fillet is formed.