SURFACE-TREATMENT OF CUTTING-TOOL SUBSTRATES

Today's research activities are concentrated on improving the properti es of cutting tools by optimizing manufacturing technologies, by alloy ing of special cutting materials and by coating of tools. As a result of the poor machinability of new cutting materials, grinding processes get more difficult, Especially in grinding of new WC-carbide and cerm et compositions, high mechanical and thermal loads influence the surfa ce topography and surface integrity of the tool. In particular, the co ating adhesion depends on the surface structure of the substrate. Vari ations of subsurface properties cause distinct differences to inferfac e strength and tool life. Influences of surface properties on film adh esion of PVD-coated carbides were investigated. Considered topics are the influence of grinding, micro blasting and water peening of carbide s on surface topography and surface integrity as well as effects on fi lm adhesion of (Ti,Al)N-coatings. Residual stress measurements and SEM -pictures were used for characterization of surface properties. Film a dhesion was analysed by scratch and indentation tests. Due to increasi ng interface strength of micro blasted tools a superior wear behaviour in dry machining was observed. (C) 1998 Elsevier Science Ltd.