Efeito da preparação de aresta em ferramentas de CBN na usinagem de aços liga

Abstract

Due to the high thermomechanical loads in machining processes, proper edge preparation is essential for achieving longer tool life and good surface finishes on the produced parts. The correct choice of microgeometry can improve stress distribution, reduce heat generation, and increase edge strength. In light of this, the present work investigates the effect of edge preparation on cubic boron nitride (CBN) tools in the machining of alloy steels. Inserts with different nominal edge radii (sharp, 20 μm, 40 μm) were produced and had their microgeometry characterized. Turning tests were conducted using annealed 4340 and hardened 4140 steels, and tool wear was evaluated. The results indicate minimal chipping on sharp tools and asymmetry in the edge rounding produced by brushing. Regarding tool life tests, the sharp-edge and 20 μm radius tools showed no performance difference when machining the annealed steel. For the hardened steel, the insert with a 40 μm preparation showed the best performance, with 22% less wear compared to the other cases. It is concluded that the appropriate choice of edge microgeometry can optimize the performance of CBN tools, especially in the turning of hardened steels, providing greater efficiency and process predictability.