Electro-Chemical Machining

Using electrolysis and by making the workpiece the anode of the dc electrical circuit, an electrolyte is pumped rapidly (under pressure) through the gap between the shaped cathode (also referred to as the tool) and the workpiece. The tool is moved slowly towards the workpiece by a ram, so that metal is progressively removed from the workpiece, until the desired shape is achieved.

The process is ideal for metals, which are difficult to machine by conventional methods and the finish achieved is good. High electric current is required and other essential requirements for the process are that the tool needs to be a good conductor (copper or brass). It must resist corrosion, because the electrolyte is often a salt solution.