Glossary of Website Terms

Anode

The work piece is electrochemical machining that is positive in polarity.

Cathode

The electrode or tool in electrochemical machining, which is negative in polarity.

Difficult Materials

Electrochemical Grinding (ECG) is an excellent process for making parts from difficult materials such and stainless steel and most high temperature alloys, such as Inconel and Hastelloy. For a complete list, click here.

EDM

Electrical Discharge Machining. A process of cutting metal by spark erosion. The electrode used is normally made of a graphite or copper (Sinker EDM). Wire EDM utilizes wire for the electrode.

Electrochemical Machining (ECM)

The controlled removal of metal by electrolyte action, without mechanical aid.

Electrochemically Reactive

Materials that are Electrochemically reactive dissolve when subjected to a flow of electricity. The rate of dissolution is inversely proportional to the valence of the material (electrons to be removed/atom) and the flow of current.

Electrode

The cathode or tool made of electrically conductive metal and having the desired contour or shape, size and so on. It is always connected to the negative terminal of the power supply in electrochemical machining.

Electrolyte

The electrically conductive fluid composed of concentrations of chemicals dissolved in water. Sodium chloride is used to machine a majority of metals, but other salts and various salt combinations have been used for cutting other metals. Dilute acid solutions are also used as electrolytes.

Faraday's Laws of Electrolysis

A theoretical basis for computing the amount of material set free, or deposited by the ECM process. The amount removed is directly proportional to the current that passes through the electrolyte from the anode to the cathode in a given time. In practice, a number of factors tend to reduce the actual rate of metal removal per ampere.

Metal Removal Rate

The volume of metal removed in a unit of time, usually expressed in cubic inches per minute. This will vary from one metal to another, depending on its chemical analysis, as well as the chemistry and temperature of the electrolyte.

Re-cast Layer

In EDM or laser cutting the material is vaporized at extremely high heat. As the molten metal cools at the surface a brittle thin layer of material develops with different mechanical properties than base metal.