Machining fixture and deformation control of aero-engine thin-walled casing

The aero-engine casing, with its thin-walled complex structure, is a critical component that significantly influences machining quality due to its low-stiffness dynamic characteristics. In this study, we propose a multi-point flexible adaptive clamping technology to enhance the local stiffness of large-scale aero-engine casings. This approach aims to mitigate deformation during milling and drilling processes and improve precision throughout the multi-process machining procedure. Firstly, we analyze the milling and drilling processes involved in multi-process machining of aero-engine casings and construct a comprehensive error transfer model that considers both geometric errors and coupling effects caused by machining deformation. Furthermore, we elucidate the principles behind positioning using multi-point flexible clamping fixtures and controlling machining deformation. Finally, through simulation analysis of machining errors as well as actual machining experiments, we verify the effectiveness of our proposed multi-point flexible clamping fixture in suppressing deformation during milling and drilling processes. Our results demonstrate that this method effectively controls casing deformation during machining: it reduces flatness error at the casing mounting edge by 38.3%, while decreasing verticity error and position error at the casing mounting hole by 40.2% and 33.1%, respectively.