Electrical Discharge Machining (EDM) is a well-known process, which is mainly used to machine difficult-to-cut, conductive materials. Die-sinking EDM, wire EDM and EDM drilling are widely used in turbine blade machining. Optimization of EDM machining strategies is permanently aimed to achieve the highest precision in minimal machining time, and therefore, to reach better quality and higher efficiency. Reduction of the process chain, which is proposed in this work by performing more operations using a single machine tool, allows the reduction workpiece reclaiming and leads to positioning error minimization. The new strategy in EDM milling and shaping described in this work allows to machine complex geometries by using a standard cylindrical shape rotary electrode, which with some limitations can be used instead of the complex die-sinking electrode. This new strategy is used for complex-shaped diffusors machining in Inconel 718 turbine blades. The comparison between state-of-art layer-by-layer milling strategy and the new method is shown. Correlation of the electrode wear pattern after EDM drilling and EDM milling with the geometry of the machined cavities is applied. The presented new method is more than 15% faster in comparison with the layer-by-layer machining strategy, whereas has higher geometrical accuracy at the same time.
展开▼
