Flank wear of CBN cutting tools of various compositions

Abstract

In this paper, sintered CBN cutting tools of various composition are tested in the cutting of chromiummolybdenum steels (JIS, SCM435H) of various hardness for the purpose to clarify their flank wear characteristics. The tool wear, cutting forces, cutting temperature and surface roughness are measured. The variation of the shape of CBN grain on tool flank are examined through SEM, and the amount of deposited metals on tool flank are analyzed through EPMA in the test. The results obtained are as follows: (1) The flank wear of CBN cutting tool is caused by the wear of CBN grain itself and also the wear of bonding materials which results in the falling off of CBN grains. (2) CBN tool of 60% CBN contents indicates the minimum flank wear. (3) The flank wear of CBN tool is reduced by using small size grain of CBN. By using the mixed grains of small size and large size, the flank wear is reduced further.