Using diamond coated tool-electrodes for drilling micro holes with EDM

Due to its thermal working principle and its independency of the work piece's mechanical properties, Micro Electrical Discharge Machining (EDM) is predestined for fabricating holes with diameters of below dh = 200 m at minimum tolerances of ± 1 m. Besides the use of special pulse generators providing discharge currents of down to ie = 100 mA at discharge durations of te 40 ns an important process factor is the tool electrodés material which has a great influence on the machining time and result, and the electrodés wear [1, 2, 3]. To assure an efficient process at a high accuracy and a low tool wear, basic properties demanded for electrodes are an excellent electrical and thermal conductivity as well as a high melting temperature, and a high mechanical strength.