The effects of grinding process parameters of a cemented carbide micro-drill on cutting edge burr formation

In the forming grinding of a cemented carbide micro-drill, edge burrs are generated. To explore the formation of the edge burrs, the grinding parameters, such as feed rate, grinding depth, wheel service time, and wheel rotation, are analyzed experimentally. Results show that the burrs on the micro-drill edge are caused by material plastic flow and cumulative effect of deformation under the grinding wheel cutting edge. At the same time, the greater the grinding depth, the greater the material flow and accumulation, and the bigger the edge burrs. When decreasing the feed rate to the grinding wheel, the number of grinding cycles will be increased, and the material accumulation on the micro-drill edge can be removed timeously by abrasive particles. This brought considerable relief in edge burr formation. The grinding wheel turning direction has a significant effect on material plastic deformation and its flowing. The cutting angle of abrasive particles is an acute angle when the grinding wheel rotates clockwise, much material accumulates near the blade, and the edge burrs on the blade are bigger. The cutting angle of an abrasive particle is obtuse when the grinding wheel rotates anticlockwise. The material is gathered towards the back face and departs from the micro-drill with no edge burrs being generated. When the grinding wheel is sharp, there are no distinct edge burrs generated. The results also show that, after grinding for 72 h, the edge burrs are generated as the sharpness decreases: the longer the grinding wheel is used, the bigger the edge burrs.