文档介绍：Advanced Manufacturing Technology ? EDM is a machining method primarily used for hard metals or those that would be impossible to machine with traditional techniques. One critical limitation, however, is that EDM only works with materials that are electrically conductive . EDM or Electrical Discharge Machining, is especially well- suited for cutting intricate contours or delicate cavities that would be difficult to produce with a grinder, an end mill or other cutting tools . Metals that can be machined with EDM include hastalloy, hardened tool- steel, titanium , carbide, inconel and kovar. ? EDM is sometimes called "spark machining" because it removes metal by producing a rapid series of repetitive electrical discharges. These electrical discharges are passed between an electrode and the piece of metal being machined. The small amount of material that is removed from the workpiece is flushed away with a continuously flowing fluid. The repetitive discharges create a set of essively deeper craters in the work piece until the final shape is produced. ? There are two primary EDM methods: ram EDM and wire EDM. The primary difference between the two involves the electrode that is used to perform the machining. In a typical ram EDM application, a graphite electrode is machined with traditional tools. The now specially- shaped electrode is connected to the power source, attached to a ram, and slowly fed into the workpiece. The entire machining operation is usually performed while submerged in a fluid bath. The fluid serves the following three purposes: Advanced Manufacturing Technology ? flushes material away ? serves as a coolant to minimize the heat affected zone, thereby preventing potential damage to the workpiece ? acts as a conductor for the current to pass between the electrode and the workpiece. Advanced Manufacturing Technology ?In wire EDM a very thin wire serves as the electrode. Special brass wires are typically used; the wire is slo