Electrochemical machining (ECM) is a method of removing metal by an electrochemical process. It is normally used for materials that are difficult to machine using conventional methods. Currently, ECM can only be used for electrically conductive materials. ECM can cut both external and internal geometries. It works on small or odd-shaped, intricate contours or cavities in hard and exotic metals, such as titanium aluminides, Inconel, Waspaloy, and high nickel, cobalt, and rhenium alloys.
The ECM cutting tool (cathode) is guided along the desired path close to the work but without touching the workpiece (anode). The pressurized electrolyte is injected at a set temperature to the area being cut. The feed rate is the same as the rate of liquefaction of the material. As electrons cross the gap, material on the workpiece is dissolved, as the tool forms the desired shape. The electrolytic fluid carries away the metal hydroxide formed in the process. The ECM process is most widely used to produce complicated shapes such as turbine blades.