Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Cutting tool materials for machining green powder-metallurgy composites

Certain green powder metallurgy materials can present considerable machining difficulties; notably very rapid rates of tool wear and excessive surface and edge "breakouts". Considering the composition and microstructure of green PM materials, the levels of tool wear experienced are unexpected and have been identified as somewhat unique among the more usual tool wear mechanisms (associated with the machining of conventional cast or wrought work materials).With regards to the issue of component quality, a series of cutting tool edge geometries were designed and manufactured and following turning tests at the Technical University of Berlin, were found to result in a considerable improvement in surface quality due to reduced surface-breakouts. For drilling applications, several methods were assessed for the production of PCBN-tipped drills.

One method, comprising a tapered PCBN segment brazed to a cemented carbide drill blank was used by Guehring for the production of twist drills and in a series of drilling tests on green PM materials, was found to result in excellent (mirror-like) surface quality and minimal edge breakouts.With regards to the issue of cutting tool wear, only one particular soft magnetic composite (SMC) PM material was found to result in significant rates of tool wear. Following extensive testing and investigation of the tool wear mechanisms, a series of novel cutting tool materials were produced using newly developed proprietary technology which despite not providing the anticipated improvements in wear resistance will help advance cutting tool materials technology for PM materials and beyond. Arising from the wear mechanism studies, Element Six also promoted the use of machinability-enhancing additives to the SMC material the results are somewhat positive through not in all machining applications.

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Reported by

Element Six Advanced Materials
- Co Clare