Many manufacturing companies that employ multistage machine tools for high-speed manufacturing are seeking methods of reducing the downtime of machine tools when tool changes are necessary because of either worn or broken cutting tools.
The use of thin-film hard coatings is not a new technology. The traditional thin-film hard coating is titanium nitride (TiN). TiN coatings have been known for many years. The method of application of the coating technology was originally developed by physical vapor deposition (PVD) back in the late 1970s. The problem with this type of technology was its elevated process temperature and, of course, the toxic gas effluent removal.
It then developed into the technology of low temperature under low-pressure conditions of PVD. This technology had the great advantage of low-temperature process conditions and, thus, the reduction in distortion. Further, it produced a very hard surface of approximately 1900 to 2300 HV. The substrate was generally pre-hardened and tempered to support the deposited layer. The substrate of high-speed steel was in the region of 820 HV (64 HRC).