Performance of two graphite electrode qualities in EDM of seal slots in a jet engine turbine vane

EDM may be the only method available when manufacturing deep slots in low machinability materials. This paper concerns manufacturing of “seal slots” in Ni-based turbine vanes. Performance in respect to MRR and electrode wear is compared for two graphite qualities. Correct electrode material is important for productivity and profitability of the manufacturing. Poco AF5 and Poco EDM3 were tested in a 23 factorial test. Two levels of discharge current and pulse duration were tested. The results show that EDM3 graphite performs very well giving significantly higher MRR than AF5, but still with acceptable relative electrode wear. The AF5 gives significantly lower wear, but also lower MRR.