Maximum free distance method for electrode feeding path planning in EDM machining of integral shrouded blisks

The application of integral shrouded blisks improves the aerodynamic efficiency and reliability of aerospace engines, while their semi-closed geometrical structures, high blade profile accuracy and difficult-to-cut material properties bring great challenges to their manufacturing. Electrical discharge machining (EDM) is regarded as an effective way to produce this kind of parts. In this paper, an electrode design method for EDM machining of integral shrouded blisks from a primitive electrode by electrode size reduction and electrode division was described. A new electrode feeding planning method named maximum free distance was presented, in which the position and attitude of a new electrode feeding path node was optimized by maximizing the distance that the electrode is able to move along a predefined reference direction before it interferes with the blisk. The feeding path sparsification was conducted to improve the workpiece debris evacuation and to save the machining time. The example of EDM machining an integral shrouded impeller with 1 in 2 out flow channels was given to validate the proposed electrode feeding path planning method.