Diamond grinding wheel wear characterization after finishing cemented tungsten carbide cutting inserts

Knowledge related to the abrasive tool wear during grinding of cemented tungsten carbide cutting inserts is essential, as this operation provides final geometry and dimensions as well as appropriate surface and edge quality. Within this context, the present work aims to characterize the wear of a diamond grinding wheel and to assess its effects on the insert surface characteristics and grinding force components. For this, grinding forces, surface and edge quality parameters were measured and the grain protrusion and the number of active cutting edges were analyzed through the measurement of roughness parameters of the grinding wheel abrasive layer by focus-variation microscopy. The abrasive topography was assessed directly in the microscope and through a mold produced with photopolymerizable resin. During grinding, grain protrusion oscillated between 2 and 6 & mu;m, surface roughness presented values between 1.5 and 2.5 & mu;m and edge roughness remained approximately constant, with a value of 2 & mu;m. The obtained results showed an initial decrease in the grain protrusion and a consequent increase in the grinding forces with the increase in the material removal volume. After grinding of greater volumes, however, the occurrence of self-sharpening was observed, which led to increased grain protrusion and reduced grinding forces. This phenomenon contributed to an increase in the number of active cutting edges in the abrasive layer and caused a reduction in the insert surface roughness.