Geometrical Analysis of Wire Electrochemical Machining for the Manufacture of Turbine Disc Slots

Abstract

The advantages of sinking electrochemical machining (ECM), e.g. best surface integrity, are always faced with the cost-intensive initial effort for the component specific design of a machining device and its tool geometry. However, this disadvantage does not apply to wire ECM where no task-specific tool design is required for cutting 2.5-dimensional geometries like fir tree slots in turbine discs. An industrial application is still being hindered by insufficient flushing concepts. However, a previous study showed that the flushing approach of High Speed Wire Electrical Discharge Machining (HSWEDM) is also successfully transferable to wire ECM. Workpiece heights up to 40 mm could be machined with a cutting rate of Vw = 20 mm2/min. Nevertheless, these investigations were only performed with straight cuts, radii were not examined. Therefore, in this paper the geometrical accuracy of the wire ECM process is analyzed using the example of two different turbomachinery disc slot geometries with 20 mm and 40 mm heights by a coordinate measuring machine.