Self-Tuning Algorithm for Tuneable Clamping Table for Chatter Suppression in Blade Recontouring

Abstract

The production and repair of blades for aerospace engines and energy turbines is a complex process due their inherently low stiffness and damping properties. The final recontouring operation is usually performed by milling operations where regenerative chatter is one of the main productivity limiting factors. With the objective of avoiding specific stiffening fixtures for each blade geometry, this paper proposes a semi-active tuneable clamping table (TCT) based on mode tuning for blade machining. The active mode of the device can be externally controlled by means of a rotary spring and eddy current damping modules. Its in-series architecture allows damping to be introduced to the critical mode of the thin-walled part without any direct contact in the machining area and enables a more universal clamping. Its chatter suppression capabilities are maximized by means of a novel self-tuning algorithm that iteratively optimizes the tuning for the measured chatter frequency. The benefits of the iterative algorithm are validated through semidiscretization and initial value time-domain simulations, showing a clear improvement in blade recontouring stability compared to regular broad-bandwidth tuning methods.

Five-axis toolpath re-scheduling for facilitating assisted supporting thin-walled blade machining by decreasing axis sensitivity

“…Ratchev et al [7] and Richter-Trummer et al [8] predicted the machining deformation of the blade by analyzing the force interaction and measuring the residual stress, respectively, to select the best machining parameters to ensure the machining accuracy and shape of the blade by reducing the deflection deformation of the parts. In view of using external equipment, a special flexible clamping is often adopted, for example, Hao et al [9] and Sanz-Calle et al [10] adopted the self-adaptive auxiliary fixture of lowmelting-point alloy which have simple structures and the semi-active tune-able clamping table (TCT) based on mode tuning to improve the local stiffness of the workpiece during machining. The first type of method is widely used at present.…”

Vibration Suppression with Use of Input Shaping Control in Machining

“…The authors of [ 42 ] presented a method for continuous spindle speed control with a vibration prediction algorithm intended to improve the quality of machined long thin blades. Counteracting vibrations can be achieved through the use specially designed, dedicated fixtures and clamping devices which fix the turbine blade in place during machining [ 43 , 44 , 45 ].…”

Adjusting the Stiffness of Supports during Milling of a Large-Size Workpiece Using the Salp Swarm Algorithm

“…The electromagnetic force between the magnets and coils generates negative stiffness, which can be tuned online by controlling the current. In [ 23 ], the authors present an algorithm for tuning a semiactive clamping table for the purpose of chatter suppression in turbine blade recontouring. The damping of the table is provided by the adjustable eddy current damping modules.…”