Chatter suppression in thin-walled part machining via conformal flexible clamping

Undesirable vibration and even chatter often occur during the unstable machining process of thin-walled parts. As an integral part of the machining system, machining fixtures play an important role in stable machining. This study proposes a novel flexible fixture system (FFS) with conformal flexible clamping, which combines curved shape retention and sufficient clamping force. The proposed FFS leverages bilateral flexible clamping forces to provide stiffness and damping, suppressing tangential vibrations at the clamping interface and transducing vibration control to the normal direction at machining points. A fixturing-machining dynamic model for conformal flexible clamping is then developed to systematically evaluate the impacts of the fixture parameters on the machining dynamics and chatter stability. Afterwards, the stability improvement mechanism of conformal flexible clamping is studied. By adjusting the clamping position and tangential stiffness, the tool-workpiece-fixture system's dynamics can be optimized to suppress chatter and reduce forced vibrations. An FFS with integrated clamping position optimization is then designed with process flexibilities for adapting to complex workpiece shapes, workpiece-tool motion, and machining dynamics. A case study for thin-walled blade machining applications shows that chatter is suppressed, the vibration amplitude is reduced by 90.1 %, and the quality of the finished surface is improved. High damping performance, extensive adjustability for workpiece-fixture system dynamics, and the flexibility to adjust fixture parameters throughout the machining process provide a high potential for stable machining of thin-walled parts.