Electrical discharge machining of carbon fibre composite materials

An investigation has been made into the feasibility of using Electrical Discharge Machining (EDM) as a means of machining carbon fibre composite materials. Machining was preformed at various currents, pulse durations and with different tool materials and polarities. There exists an optimum material removal rate with peak current and the pulse-on time. However, electrical discharge machining of carbon fibre composite materials should be done at low current density as high current density would cause the epoxy resin to smear over the surface leading to reduced material removal rate and rapid deterioration of the EDM surface. It is found that copper electrodes perform better than graphite electrodes in terms of tool wear, and tools with positive polarity give higher material removal rate and lower tool wear ratio.