In this process material is removed by electro chemical dissolution.

I. Electro-chemical machining (ECM)

II. Electro-chemical grinding (ECG)

III. Electro jet drilling

Principle of Electro-chemical machining (ECM):

• This machining process is based on Faradays low of electrolysis.
• It states that the weight of substance produced during electrolysis is directly proportional to the current which passes, the length of time of the electrolysis process and the equivalent of the material which is deposited.

Working of Electro-chemical machining (ECM):

• The diagram of electro-chemical machining is shown in figure.

Electro Chemical Machine

• It is basically a process which is the reverse of electroplating.
• The electrolytic action is used for removing the metal.
• In contrast to electroplating a high current density is used in ECM.
• The process involves the passage of current through an electrolyte in the gap between the work piece (anode) and the tool (cathode).
• The metal removal rate depends on the current density which is a function of conductance of the electrolyte and voltage applied as well as the shape and the gap between the electrodes.
• The chemical reaction that occurs in ECM is the conversion of metal into its hydroxide.
• The metal hydroxide is dissolved in the electrolyte and is washed away by the circulating electrolyte.

Advantages of Electro-chemical machining (ECM) :

• High surface finish rate.
• No sharp edge and burrs remains on the work piece.
• Extremely thin sheet can be easily worked.

Disadvantages of Electro-chemical machining (ECM):

• Non conducting material cannot be machined.
• The specific power consumption is more.

Applications of Electro-chemical machining (ECM):

• Cutting slots in a valve plates.
• Machining of turbine blades.
• For cutting cavities in forging dies.