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.
Highlights
The manufacturing and repair of fan, compressor and turbine blades constitute very high added-value industrial processes with a high relevance in the aerospace manufacturing industry
These operations have traditionally been performed through manual belt grinding, the need to automate the process to the extent possible has encouraged the engine part maintenance industry to move towards milling-based recontouring, performed on 5-axis machines or hybrid cells in which welding and machining operations are performed in the same clamping [7,8]
This paper presents a self-tuning algorithm for the tuneable clamping table for efficient blade manufacturing and repair
Summary
The manufacturing and repair of fan, compressor and turbine blades constitute very high added-value industrial processes with a high relevance in the aerospace manufacturing industry. The aim of the recontouring stage is to remove, by machining operations, the excess material added in the welding stage (see Figure 1a,b) using additive manufacturing technologies such as laser cladding [5] or laser metal deposition [6] and achieve the final blade geometry These operations have traditionally been performed through manual belt grinding, the need to automate the process to the extent possible has encouraged the engine part maintenance industry to move towards milling-based recontouring (see Figure 1c), performed on 5-axis machines or hybrid cells in which welding and machining operations are performed in the same clamping [7,8]. Active dampers can improve the dynamic stiffness of the part by counteracting the measured vibration by means of an actuator This idea has recently been implemented to successfully damp flexible parts during heavy duty milling operations on thin walls [15]. The algorithm is validated through semidiscretization and initial value time-domain simulations, showing a superior performance compared to regular wide-bandwidth tuning methods
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