Aspects of plasma-enhanced magnetron-sputtered deposition of hard coatings on cutting tools

Plasma-enhanced magnetron-sputtered deposition (PMD) is a physical vapor deposition process that combines plasma–ion bombardment with conventional magnetron sputtering to produce wear-resistant coatings with unique microstructural and tool-wear properties. With respect to microstructural properties, TiN deposited using the PMD process shows a very fine grain size and high internal stress with excellent adhesion and cohesion properties. With respect to tool-wear properties, end mills, shaper cutters, and hobs coated with TiN using the PMD process, show improved life when compared to those using arc-evaporation and unbalanced magnetron sputtering processes. The microstructural and tool-wear characteristics are believed to result from the plasma and ion-bombardment properties of the PMD coating process. In this paper, we present a summary description of the PMD plasma–ion bombardment process as well as gear-cutting wear measurements for PMD-coated cutting tools.