Introduction to EDM
A method of processing a material by using a corrosion phenomenon generated by spark discharge is called electric discharge machining. EDM is a spark discharge in a liquid medium at a lower voltage range. EDM is mainly done by the machinery factory. The electric spark is a self-excited discharge, and its characteristics are as follows: The two electrodes of the spark discharge have a higher voltage before the discharge, and when the two electrodes are close, the medium is broken down, and then a spark discharge occurs. With the breakdown process, the resistance between the two electrodes sharply decreases, and the voltage between the two poles also sharply decreases. The spark channel must be extinguished in time after a short period of time (usually 10-7-10-3 s) to maintain the "cold pole" characteristic of the spark discharge (ie, the thermal energy of the channel energy conversion is too late to reach the depth of the electrode). The channel energy acts on a very small range. The effect of the channel energy can cause the electrode to be partially corroded.