The electrode is electrically charged by a servo-controlled generator producing the spark. Water based dielectric flushes through and around the electrode providing a controlled environment for the spark to jump to the work piece. The electric spark erodes the surface of the work piece creating very small pockets. Eventually millions and millions of these microscopic pockets create the small hole. The size of the hole is controlled by the diameter of the electrode. The location and depth of the holes are driven by CNC ISO codes, reducing and eliminating operator error. Machines shown have automatic electrode changers for unattended machining.
Small hole edm is in many ways similar to a drilling operation but it offers the advantages of edm. Very low machining and work piece hardness are not barriers to performance.