Rotating curvilinear tools for EDM of polygonal shapes with sharp corners

Flushing of the inter-electrode gap is of critical importance in the performance of electrical discharge sinking operations. When the provision of flushing holes in the tool or the workpiece is impractical, effective flushing is best realized by inducing a relative motion between the electrodes. This paper relates to a novel application inspired by the kinematics of a Reuleaux Triangle that facilitates flushing through synchronous orbiting of a rotating curvilinear tool. This innovative scheme enables the machining of regular as well as non-regular polygonal shapes with sharp corners. Experimental results from implementing this concept on a 4-axis CNC EDM machine tool are presented.