Wire EDM
Machining Services

As with all EDM machining, measured voltages between two electrodes are required to produce a current of electricity. These electrodes create a spark, generating temperatures of over 14,000°F to vaporize and erode the material being machined. With wire EDM, voltage is sent through the wire and a current path is established between the work piece and the wire, which serve as the two electrodes. A precise servo motor ensures constant gap between the wire and the piece. If the wire were to touch the work piece, a short circuit would occur, stopping the process. In some ways, it is helpful to compare the wire EDM cutting action to that of a band saw, except the teeth of the band saw are replaced with the spark, which jumps from the wire to the work piece nearly a million times per second to erode the material. Eroded materials shed from the work piece are no larger than specks of dust. Like a band saw, the thin wire is spooled and constantly fed between two computer assisted guides. This constant spooling action provides a fresh cutting surface throughout the wire cutting process. Because the cutting action produces constant erosion of both electrodes, long lengths of wire must be used – around 11 miles long (19 km) – and spools can weigh about 18 pounds, depending on the wire’s gauge. Once the cutting dimensions are entered into the CNC machine, the process is ready to begin. De-Ionized Water: Wire EDM Cutting Medium Pressurized and de-ionized water, or any dielectric fluid, provides resistance to the spark. This resistance helps to precisely control the level of voltage jumping from the wire to the work piece, providing a consistent cut. Unfiltered water does not work for this purpose. The minerals present in normal water act as a conductor of electricity which would mean uncontrollable cutting at lower levels of voltage. Resin tanks filter out the minerals, producing pure de-ionized water, which does not conduct electricity under normal circumstances. Only after enough voltage is applied will dielectric fluid ionize to conduct a current. Dielectric water also serves to flush any shed material from the environment, ensuring a clean cut.