What is it?
Sinker EDM uses a machined graphite or copper electrode to burn pockets that are in the shape of the electrode. The electrode is plunged into the part vertically, and electronic guidance adjusts the feedrate of the electrode so that a continuous arc passes between the work and the electrode. This arc vaporizes the material at the gap. The vaporized particles are flushed away by a dielectric oil that passes through the center of the electrode and into the pocket. The oil also serves to cool the electrode and the part.
What can it do?
This machining method can burn geometry that is difficult or impossible with other methods, including wire EDM. Like all EDMs, it can also machine hard or heat-treated metals. The finish on machined surfaces is about the same in appearance as a blasted finish, and the quality can be varied.
Is it for me?