Simulation of the pulsed electrochemical machining (PECM) of thin-walled workpieces for turbomachinery component manufacturing – SIMPECT

• Applicants: Dr.-Ing. Andreas Klink; Professor Dr.-Ing. Wolfgang Schröder
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering ; Fluid Mechanics
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 439915866

In turbomachinery component manufacturing, the increasing thermal and mechanical requirements of more efficient engines require continuously higher-temperature materials, which are increasingly difficult to be processed conventionally. In particular, in blade production – in addition to high dimensional accuracy and surface finishes – the machining of thin-walled components is needed. These requirements are extremely difficult to be achieved technologically and economically by established machining processes due to the large process forces and the immense amount of tool wear. As a result, electrochemical machining (ECM) is more and more often used as an alternative by engine manufacturers. The material removal is independent of thermo-mechanical strength values due to anodic metal dissolution. The physical electrolyte properties and the fluid flow conditions are the elementary process influencing variables. They play a key role for the locally realizable material removal. For finishing of blade geometries usually pulsed electrochemical machining (PECM) technology is used, resulting in higher surface finish and manufacturing accuracy. The industrial application of the method shows, however, that flushing-induced phenomena can occur leading to shape deviations or even short circuits, especially in filigree components. There is no validated fluid dynamics simulation model for tool design in the PECM process. The reason lies in the strong unsteadiness in the electrolyte channel due to the oscillation of the tool electrodes and in the fluid-structure interaction during processing. In the first project funding phase, a generic environment for the simulation and measurement of flow and structural mechanical characteristics of the PECM process was successfully established as a basis. In the second phase, the targeted model development for the influence of flushing-induced forces and for the description of the accumulation of gas agglomerates on the electrochemical removal behavior of a real blade geometry was realized and applied. The aim of the third funding phase is to develop a tolerance-based decision model for the target-oriented selection of machining parameters for process optimization. This goal is to be achieved by combining highly efficient simulation models and precise experimental measurements. Based on this holistic understanding of the PECM process, the model is then developed, which uses simulation methods with greatly reduced complexity to determine, among other things, the static and dynamic structural properties of the workpiece and the material removal to be expected locally.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2231: Efficient cooling, lubrication and transportation – coupled mechanical and fluid-dynamical simulation methods for efficient production processes (FLUSIMPRO)