Application of foil electrodes for electro-erosion edge honing of complex-shaped carbide inserts

Electro-erosion honing is a novel process that exploits the undesirable but inevitable phenomenon of localized electrode wear in sink electrical discharge machining that rapidly rounds off sharp edges, for the edge honing of cutting tools. The process essentially entails the sinking of a sharp edge of a cutting tool into a counterface of an appropriate material to generate the round edge geometry. This paper proposes the innovative application of a foil counterface, with a view to expanding the capability of this process in the honing of tools with such geometric features as nose radii and curved edges. Such a configuration involves no particular alignment requirements, and facilitates the simultaneous processing of a batch of inserts. In consideration of their industrial significance, the process is evaluated in the honing of cemented carbide inserts. The novel process is demonstrated to address the limitation of the conventional brush honing process in being capable of generating consistent edge geometry, while delivering comparable tool life.

► The novel application of foil counterfaces for the electro-erosion edge honing of inserts with nose radii and curved edges is presented. ► The process is configured for the edge honing of cemented carbide inserts with no binder depletion. ► The tool life of inserts prepared thus is comparable to that of brush honed inserts. ► The variability in edge radius is less than 15% which is significant in terms of ensuring a robust process response.