To clarify the tool wear mechanism in cutting fiber reinforced metal (FRM), turning three kinds of FRM were carried out. They are two kinds of SiC whisker reinforced Al (A6061) and Al2O3 short fiber reinforced Al (A6061). In cutting them, it is known that severe tool wear is observed. So, the tool wear mechanism in cutting them was investigated. Tool materials were five kinds of cemented carbides, two kinds of ceramics and the sintered diamond. In comparison in the cemented carbides, there is the difference of the tool wear by the Co content, the hard grain of the tool and the grain holding strength of the binder. And there is the difference of the wear mechanism in comparison in the three work materials. In cutting SiC whisker reinforced Al (A6061) with the cemented carbide, the tool wear seems to progress due to both of the simple abrasive wear and the falling off of the hard grains. This falling off is produced so that the binder is cut away by the very thin whisker. On the other hand, that in cutting Al2O3 short fiber reinforced Al (A6061) seems to progress due to only the simple abrasive wear. In cutting with two ceramic tools, the severe tool wear is observed in spite of the high hardness. In the diamond tool, the tool wear is very small and this is the most suitable tool in cutting FRM.
