Performance of single-crystalline and nanometer-sized- polycrystalline diamond tools in cutting cobalt-free tungsten carbide under face turning

摘要

This paper describes the analysis of cutting performance of a single-crystalline diamond [SCD] tool and a nanometer-sized-polycrystalline diamond [NPCD] tool under continuous V-grooving of cobalt-free tungsten carbide. The cutting experiment was conducted using a face turning system with an aerostatic rotary table set on a surface grinding machine. Wear height of the tool edge under V-grooving for the SCD and the NPCD tool was 4.8 μm and 2.3 μm respectively after 440 m grooving. Tool edge of the SCD showed a larger proportion of cleavage compared with abrasive wear, while abrasive wear was dominant when the NPCD tool was used. Plastic flow of tungsten carbide was observed at the bottom of the V-groove and brittle fracture occurred at the edge of the groove when the NPCD tool was used. Transcrystalline and plastic flows were observed in chips resulting from use of each diamond tool. The NPCD tool showed superior performance when cutting tungsten carbide under V-grooving as compared to the SCD tool.