Electrical discharge machining (EDM) is one of the major manufacturing technologies in order to produce high-precision and complex features into hard-to-cut materials. For tool wear compensation, various tool electrodes need to be applied. The production of these tool electrodes is a cost and time intensive part of the process chain.
For reducing the number of required tool electrodes, wear resistant tool electrode materials need to be investigated. High thermal conductivities, high specific heat capacities and high melting temperatures are beneficial for tool electrode materials. These characteristics are met by the material tungsten carbide-cobalt. The die-sinking EDM with tool electrodes made of different tungsten carbide-cobalt grades in workpieces made of tool steel has already been investigated. Within this work, the high temperature nickel-based alloy MAR-M247 was used as workpiece material. Nickel-based alloys are a common group of materials for turbomachine components, where EDM is frequently applied for manufacturing of specific features like seal slots or similar.

The cobalt content tends to have an impact on the wear behaviour. With increasing cobalt content a decrease in relative tool wear can be observed until a certain value, which differs depending on the grain size of the tungsten carbide grains. The group representing the highest grain size reaches the lowest values for relative tool wear. The minimum tool wear of 5.1 % occurs in this group for a cobalt content below 10 %. Lower grain sizes go together with higher relative tool wear. Nevertheless, the maximum relative tool wear of 31.0 % is generated for a grain size of 0.21 µm due to a non-comparable low cobalt content of 0.8 % for this tungsten carbide-cobalt grade. Further investigations will include the thermophysical properties of the tungsten carbide-cobalt materials for defining a tool wear resistance coefficient for this group of materials.