Research on adaptive CNC machining arithmetic and process for near-net-shaped jet engine blade

Near-net-shaped jet engine blade machining process have better performance on both reducing material waste during production and improving work reliability in service, while precision machining of this blade is very challengeable and difficult due to its positioning difficulty and low stiffness. This paper propose that reasonable fixture and adaptive CNC machining technology can provide a systematic solution for the machining of near-net-shaped blade Tenon root, tip and Leading edges and Trailing edges (LTE). Firstly, process characteristics, difficulties and requirements of near-net-shaped blade are analyzed. Secondly, adaptive CNC machining process and its key technical principles are introduced and optimized, and proposes measuring bad points culling algorithm of simultaneously using distance relationship, angle relationship and radius relationship, and proposes camber line calculation algorithm of equidistant offset, and optimizes the iterative closest point (ICP) algorithm based on point-to-line ICP algorithm with six control points, and realizes the reconstruction of processing model. Finally, the feasibility of the proposed adaptive CNC machining process and the designed Polyetheretherketone (PEEK-GF30) material and multi-points support rigid-flexible coupling fixture are verified by a typical near-net-shaped blade LTE and Tenon root adaptive CNC machining process experiments. The results shows that the proposed process scheme of reasonable fixture and adaptive CNC machining process can solve two problems of near-net-shaped blade manufacturing of position difficulty and low stiffness. The designed fixture of PEEK-GF30 material and multi-point support rigid-flexible coupling, and the optimized adaptive CNC machining process algorithms can realize high-precision manufacturing of near-net-shaped jet engine blade.