Analysis and optimization of the machining fixture system stiffness for near-net-shaped aero-engine blade

Low stiffness of the near-net-shaped blade machining fixture of aero-engine creates challenges for the CNC machining accuracy and efficiency of near-net-shaped blade. This study aims to optimize the fixture’s material and structure to improve the stiffness of the blade-fixture system. First, the main influencing factors of the near-net-shaped blade tenon root CNC machining process were analyzed, and the influences of the positioning and clamping component materials and structures on the stiffness of the machining fixture were analyzed based on finite element analysis (FEA). Second, the mechanical properties of the positioning and clamping components of different materials and structures were analyzed based on cross-scale analysis from microscopic and macroscopic perspectives. Finally, the positioning and clamping components of the machining fixture were designed based on material selection and structure optimization, and the optimized machining fixture with new material and structural was verified by CNC machining process. The results showed that the material and structure of the positioning and clamping components were the main influencing factors of the machining fixture stiffness. The positioning and clamping components of the PEEK-GF30 material of the new splicing structure could effectively improve the blade-fixture stiffness.