Electro Chemical Machining (ECM) is a machining method in which material removal is achieved by a controlled dissolution process. Under the influence of electrical power and a saline solution, miniscule metal particles are dissolved. These particles are washed away by the electrolyte flow, as a result the material is reduced in size.

The dissolution of material is greatest near the electrode, the further away the less influence the process exerts on the object. The electrode is gradually moved towards the material (maintaining a small gap) until the desired depth is reached and the product has its intended shape. The electrode is a key element in the process since it is "copied" onto the raw material. The ECM process has the advantage that electrode wear is negligible, consequently high standards of precision and reproducibility can be achieved.