HIPIMS coated carbides with high adhesive strength for hard machining

Abstract

Hard processing is defined as the machining of ferrous materials with a hardness of at least 50 HRC. Due to the possibility of the substitution of grinding processes, hard processing has grown in importance in recent years. Fundamental to this was the development of heat and wear resistant cutting materials. The turning of hardened steel is currently possible with cubic boron nitride and ceramic tools, however, hard metals offer a higher versatility and optimization potential. With a choice of different substrate compositions, grain sizes, micro and macro geometry and hard coatings, modern manufacturing technology has a large range of tool combinations. By progressive developments in the field of PVD coating technology it is now possible to deposit hard, dense and smooth layers with sufficient toughness by the application of the HiPIMS (High Power Impulse Magnetron Sputtering) process. In this contribution cemented carbide cutting inserts in combination with varying TiAlN HiPIMS films are studied with regards to their wear behavior in model wear test rigs. The tools are tested not only with regard to their individual wear resistance, the layer adhesion compared with conventional DCMS (Direct Current Magnetron Sputtering) tools is also evaluated afterwards. After evaluating the wear of the HiPIMS layers a promising film-substrate system for the cutting tests is selected. The use and wear behavior of the HiPIMS tools is compared to the behavior of the DCMS coated inserts. The objective is to establish the HiPIMS layer for industrial usage in the hard machining process.