Metal Matrix Composites - Mmc - Turning: Comparison of Tool Materials

The main properties required to the modem cutting tools to be employed in production, are both high wear resistance and chemical stability. In this last years, in the machining of MMCs several kinds of coated tools have been developed; they are characterized by high hardness to resist to the relevant strength and abrasive action of the reinforce fibers or particles, arranged inside the matrix. In turning of MMC the employ of Tungsten Carbide tools coated with Polycrystalline Diamond (PCD) have shown to be very effective, whereas they are very expensive thus increasing the production costs. In order to reduce the tool cost, in the present work, some other tool materials, characterized by hardness values similar to PCDs, like coated Cermet tools and CBN (Cubic Boron Nitrite), are employed in the cut of a MMC. To evaluate the possibility of employing these tools in substitute of PCDs, tool life data have been compared taking into account both their cost and the surfaces quality obtained.