Towards the evaluation of wear and time-variant process stability during milling supported by k-means cluster analyses of Raman scattering data

Tool wear dynamics, efficiency of coatings in wear mitigation and dynamic process stability are studied for C45 steel machining using uncoated and TiAlN coated end mills. The TiAlN coated tools exhibit an enhanced wear resistance evidenced by a significant reduction in wear mark width, while the process stability becomes limited. Raman spectroscopy combined with grey-box modeling furthermore highlights possible wear initiations for the TiAlN thin films and outlines that the observed wear mitigation is related to the formation of self-organized nanostructures, primarily driven by a temperature-induced spinodal decomposition of TiN and AlN phases within the coating.