Performance of CBN

In the first years of CBN at the market, it was seen as competitor to diamond. However, CBN proved soon to be an ideal complement for machining of hard to machine ferreous materials [JUCH78]. In addition, CBN has advantages in its higher thermal stability over diamond. In the beginning, CBN was bonded in metal or resin bonds, however, vitrified bonds featured the intrinsic advantages of CBN best. The first vitrified bonded tool needed additional profiling processes [STUC88, p. 113]. With newer bondings, now the dressing process with diamond dressing tools provides a sharp grinding wheel topography in one conditioning process.

Thermally induced damage with CBN tools is less of a problem compared to conventional abrasives [MALK08, p. 215; MALK85]. Not only are the specific grinding energies normally smaller for CBN grinding, but the abrasive grit material CBN has also a much higher thermal conductivity (e. g. 35 times bigger than that of corundum) [MALK08, p. 215 f.]. The comparably lower heat flux into the work­piece results in smaller tensile stresses and even favorable compressive stresses at the surface [BRIN82, p. 128].

CBN proves especially useful in high-speed grinding operations. The wear resistance of CBN is much higher than for conventional abrasives, so that CBN grinding wheels excel with G-ratios up to 1000* higher for steel grinding compared to Al2O3 tools [JACK11, p. 9 f.].

In honing tools, the usage of CBN instead of diamond enables the use of emulsion instead of oil lowering the cleaning costs for workpieces [JUCH78].

Updated: 24.03.2016 — 11:54