Experimental Investigations of Cutting Rates and Surface Integrity in Wire Electrochemical Machining with Rotating Electrode

Abstract

The advantages of ECM regarding productivity and best surface qualities are always challenged by high costs for process development and complex electrolyte flow devices. Combining the working principle of electrochemical machining (ECM) with a universal tool, like a wire, could meet these challenges. Such a wire ECM process might be able to machine flexible and efficient 2.5-dimensional geometries like fir tree slots in turbine discs. Nowadays, established manufacturing technologies for such geometries are broaching and wire electrical discharge machining (wire EDM). Nevertheless, high requirements on surface integrity of turbine parts need an intensive process development and – in case of wire EDM – trim cuts to reduce the heat affected rim zone. In the past, few studies dealt with the development of a wire ECM process to meet these challenges. However, previous concepts of wire ECM were only suitable for micro machining applications. Due to insufficient flushing concepts, the application of the process for machining macro geometries with higher cutting rates failed. Therefore, this paper presents experimental investigations on wire electrochemical machining of macro geometries. An axial flushing approach with a rotating tool electrode is used in order to optimize electrolyte flushing and thus, to increase cutting rates. The influences of different machining parameters on cutting kerf, surface integrity and cutting rate will be presented.