ARC PVD-COATED CUTTING TOOLS FOR MODERN MACHINING APPLICATIONS

Present research work in machining determined by ecological and econom ical reasons is focused on working without cooling and lubrication, hi gh speed cutting (HSC), near net shape production and rapid prototypin g. To achieve the desired aims in productivity and quality, modern hig h-performance machining tools as well as the adapted tooling machines and process parameters are necessary. In particular, the machining of tempered or austenitic steels requires complex mechanical, thermal and tribological properties from the applied tools. Since conventional hi gh-speed steel or cemented carbide tools often cannot fulfil these hig h demands, new efficient cutting tools have to be developed. This pape r presents the development of new are PVD coatings in the systems Ti-H f-C-N. The coatings were characterized due to the desired property pro file for special cutting operations. For the machining of austenitic s teels, coatings with a low friction coefficient to austenite and a hig h adhesion to the substrate are necessary. These properties were inves tigated by pin-on-disc and scratch tests. The thermophysical propertie s and thermal stability of the coatings, which play and important role in dry machining, were determined by photothermal spectroscopy, ice-t ribometer tests and high-temperature X-ray diffraction. The results of the machining tests of the new coatings deposited on cermets are pres ented in another paper. (C) 1997 Elsevier Science S.A.