EDM Drilling is the process used to produce very small, round bores in any hard or soft material and in any shaped component by conducting electrical current through brass or copper electrodes. Drilling involves the creation of holes that are right circular cylinders. This is accomplished most typically by using a twist drill, something most readers will have seen before. The figure below illustrates a cross section of a hole being cut by a common twist drill. EDM drilling is most often used to produce bores from 0,1mm diameter to approximately 3mm diameter .