AN INVESTIGATION ON FLANK WEAR MECHANISM OF TUNGSTEN CARBIDE DRILLS DURING CONVENTIONAL AND MODULATION ASSISTED DRILLING

The aim of this research was to experimentally investigate and compare the wear performance of tungsten carbide drills used in conventional and modulation assisted drilling (MAD). During MAD, modulations of low frequency and high amplitude were superimposed on tool motion in the feed direction. Direct measurement of flank wear land was used as tool condition monitoring method. Since the width of flank wear was not regular along the cutting edge, the maximum flank wear, VBmax , was measured using a toolmaker's microscope. The drills were inspected under the scanning electron microscope to establish the possible wear mechanism. The results indicate that the drills used in MAD were better in resisting tool wear than those used in conventional drilling. However, at higher feed during MAD, a catastrophic failure of drill occurred due to fracture of cutting edge.