Non-destructive testing of polycrystalline diamond cutters using dc electrical conductivity imaging

A new application of electrical impedance tomography/resistivity imaging is investigated: non-destructive testing of polycrystalline diamond cutters used for rock drilling. An instrument employing 121 spring-loaded probes to contact the diamond surface of a cutter was constructed. The acquired 4-probe dc resistance data are reconstructed using an established algorithm into a 3D electrical conductivity distribution within the diamond table. Measurements on cutter samples demonstrate the feasibility and potential utility of this imaging method. Flaws, such as metal rich zones, can be detected. The bulk conductivity is also found to be a strong function of manufacturing process parameters