Analysis of machining deformation for adaptive CNC machining technology of near-net-shaped jet engine blade

Near-net-shaped process (NNSP) will be one of important development trend in TC4 blade manufacturing, while the blade precise machining after NNSP is a challenge. This paper analyzes the machining deformation of blade under the rigid-flexible coupling fixture (RFCF) and adaptive computer numerical control machining process (ACNCMP). Firstly, positioning and clamping scheme (PCS) of RFCF were introduced and analyzed, especially new material (PEEK-GF30) and new structure of RFCF were used in fixture manufacturing. Secondly, theoretical mechanic model of RFCF and blade was proposed. Thirdly, empirical model of cutting force and the main cutting parameters was established and analyzed by orthogonal cutting experiment (OCE). Fourthly, blade deformation under cutting force was analyzed by FEA and experiment. The results show that blade cutting deformation is a whole elastic deformation of 0.056mm which is acceptable for machining accuracy target of 0.1mm. The proposed RFCF can protect blade from occurring local deformation, and is of better application value in ACNCMP of NNSP blade.