When the electric spark machining is carried out, the tool electrode and the work piece are respectively connected with the two poles of the pulse power supply, and immersed in the working liquid, or the working liquid is filled into the discharge gap. Through the gap automatic control system to control the tool electrode feed to the workpiece, when the gap between the two electrodes to a certain distance, the pulse voltage applied to the two electrode will work liquid breakdown, resulting in a spark discharge.

In the micro channel discharge in the instantaneous concentration of the heat, the temperature can reach 10000 DEG C, the pressure is also changing rapidly, so that the work surface of local trace metal materials immediately melting, gasification, and explosive splash into the working fluid, rapid condensation, formation of metal particles is solid, the working fluid. At this time on the surface of the workpiece will leave a trace of micro pits, discharge short stop, two electrode working fluid to restore the insulation state.

Next, the next impulse voltage at the two electrode is relatively close to another point breakdown, resulting in a spark discharge, repeat the process. In this way, although the metal amount of each pulse discharge is very little, but because of the tens of thousands of pulse discharge per second, the metal can be removed, with a certain amount of productivity.

In the constant discharge gap between the tool electrode and the workpiece under the condition of side etching of metal workpiece, while the tool electrode to workpiece, and finally processing corresponding to the shape of the tool electrode shape. So, as long as the shape of the tool electrode and the relative motion between the tool electrode and the workpiece can be changed, various complex surfaces can be processed. Tool electrodes are commonly used in good electrical conductivity, high melting point, easy to process of corrosion resistant materials, such as copper, graphite, copper tungsten alloy and molybdenum, etc.. In the machining process, the tool electrode also has the loss, but is smaller than the metal of the work piece, even close to no loss.

Working fluid as the discharge medium, in the processing process also plays the role of cooling, chip removal and so on. The working fluid used is low viscosity, high flash point, stable performance of the medium, such as kerosene, deionized water and emulsion etc.. The electric spark machine is a self excited discharge, which is characterized as follows: the spark discharge between the two electrodes in the discharge front with a higher voltage, when the two electrode is close, during which the medium is broken down, then the spark discharge. With the breakdown process, the resistance between the two electrodes becomes smaller, and the voltage between the two electrodes becomes lower and lower. The spark channel must be maintained in short time (usually 10-7-10-3s) after burning in a timely manner, it can keep the spark discharge of "freezing" characteristics (i.e., thermal energy conversion channel too late to make the channel energy, electrode depth) in small range. The function of the channel energy can cause the electrode local to be corroded. Method for processing the size of the material by the corrosion phenomena produced by the spark discharge is called the electric spark machining. EDM is in the lower voltage range, in the liquid medium of the spark discharge. The relative motion between the characteristics of EDM tool electrode according to the form and the workpiece, EDM can be divided into five categories: the molding tool electrode, workpiece for EDM simple feed movement; use the axial movement of the metal wire work out electrode and workpiece according to the required shape and size for to track movement, cutting electrospark wire cutting processing using conductive material; conductive wire or metal forming grinding tool electrode for rotation, small hole grinding or grinding EDM grinding; for EDM machining rotary conjugate thread ring gage, thread plug gauge, gear machining and machining; surface alloying moment English and other types of surface strengthening. The processing of common cutting method is difficult to cut materials and complex shape workpiece can EDM machining; no cutting force; no burrs and cut grooves and other defects; tool electrode materials not harder than the material of workpiece; direct use of power processing, easy to realize automation; after processing the surface modification layer, further removal shall be in some application of purification and processing; produced liquid in the smoke pollution treatment more trouble.