Effect of Electrode Route Motion on Electrode Wear in EDM Machining of Mold Steel

In the electrical discharge machining (EDM) of deep holes, electrode wear may cause the dimensions of the finished holes to deviate from their design values. In practice, the extent of the electrode wear and the surface roughness of the machined holes depend not only on the EDM machining parameters (e.g., the pulse duration, the pulse current, and so on), but also on the electrode route motion. Accordingly, the present study performs an experimental investigation into the effects of three different electrode routes (straight dip, spiral attack hole, and awl free expand hole) on the electrode wear and surface roughness of the machined holes in the EDM machining of PDS5A and PDS-1 mold steel, respectively. Overall, the experimental results show that of the three electrode route motions, the awl free expand hole motion results in a more uniform wear of the electrode and a lower surface roughness of the machined hole.