Feedrate planning for synchronized movements involving rotary axes in multi-axis EDM for shrouded blisks

As compared to traditional machining approaches, multi-axis electrical discharge machining (EDM) has its unique advantages in machining components which are made of difficult-to-cut materials and have complex structures, such as shrouded blisks. Manufacturing processes of such complex parts involve synchronized movements of both linear and rotary axes. Due to different dimensions of angular and linear velocities, there is a discrepancy between demanded and actual feedrates. This feedrate discrepancy, on the one hand, can cause feedrate fluctuations leading to a machining instability, and on the other hand, can cause inaccurate heights of electrode jumps. In order to ensure the machining stability, this paper proposes a feedrate planning method for multi-axis EDM of shrouded blisks. In this method, CAD models of both an electrode and an shrouded blisk are utilized to extract characteristic radii for feedrate planning in G-code generations. A feedrate post-processing algorithm for multi-axis EDM for shrouded blisks is proposed to reduce feedrate fluctuations and achieve a proper electrode jump height. Data analysis demonstrates the resultant feedrate can be kept in a proper range. In comparative multi-axis EDM for shrouded blisks, the machining time has been reduced by up to 21.43 % by using the proposed feedrate planning method.