Development of cBN(cubic boron nitride)-Coated Cutting Tools

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In this study, we fabricated and evaluated cBN-coated cutting tools, which may be applicable to the cutting process of difficult-to-cut materials and environmentally friendly manufacturing processes. It is well known that cBN has excellent heat resistance and antiwear properties, but its anti-tipping property is insufficient. Therefore, we consider that a cBN-coated cutting tool, in which a thin cBN film is adhered on a tungsten carbide substrate, has properties comparable to those mentioned above. First, we investiga1ed the tribological properties of the cBN film, which was fabricated by the PVD process. The results showed that the cBN film has excellent tribological properties, such as a low frictional coefficient and an antiwear property, under both atmospheric and vacuum conditions, which simulated the tool edge condition in an actual cutting operation. Next, we investigated the cutting properties of actual cutting tools, such as cBN-coated drills and ball-nosed end mills. Namely, … More we fabricated these tools and evaluated the advantageous characteristics of the cBN-coated tools through several cutting tests, such as the cutting of a mold steel workpiece. The results clarified that the fabricated cBN-coated tools have better cutting performance than conventional tools made of high-speed steel and tungsten carbide. However, we also observed that the cutting performance of the fabricated cBN-coated tools is significantly less progressive than those of conventional TiN-and TiAIN-coated tools, because the thickness and adhesion of the cBN film are insufficient. Finally, we investigated the cutting performance of the sintered cBN ball-nosed end mills with a specially designed cutting edge. It was expected that these tools have good cutting performance, similar to that of the cBN-coated tool with large-thickness and good adhesion properties. The results of our experiment clarified that the newly designed sintered cBN end mills have excellent cutting performance, compared with a conventional TiAIN-coated tungsten carbide end mill. Less