Electro-chemical machining (ECM), an advanced metal processing method, is investigated. For the implementation of the method, a unique three dimensional CNC machine is developed and customized for electro-chemical applications. A new device is developed by integrating the CNC machine with a pulsed DC power supply, a servo motor system that provides vertical gap control, and an electrolyte circulating and recycle system. The variable parameters that lead to the operation of the system within the desired limits are determined. It is found that correct cathode tool design, well adjustment of the vertical gap between the anode and the cathode, and accurate control of electric current density and voltage values are crucial in controlled operation of the system, while keeping the electrolyte concentration constant is effective on system stability.