WEAR MECHANISMS AND MATERIAL FLOW ANALYSIS IN HIGH SPEED TURNING OF SOFT GREY CAST IRON Janez Kopac, Franci Pusavec e Joze Jurkovic
Resumo: High speed machining has received important interests in automotive industry
because it leads to an increase of productivity and better workpiece surface quality. However, at high cutting speeds, the tool wear increases dramatically due to the high temperature at the cutting zone. Tool wear impairs the surface finish and hence the tool life is reduced. That is why an important objective of metal cutting research has been the assessment of tool wear patterns and mechanisms. In this paper, the wear performance of CBN tool in high speed turning is presented when cutting grey cast iron. The tool wear patterns were examined through a toolmaker's microscope. With aim to minimize tool wear also chip formation was analyzed. The research results show that the tool wear types differed in various tool geometries. The main wear mechanisms were mechanical friction, adhesion and chemical wear promoted by high mechanical and thermal influence. Hence, the important considerations of CBN cutting tool material is high heat resistance, wear resistance and chemical stability. The research results will be of great benefit in the preparation of cutting tool edge and in the control of tool wear in high speed machining processes.
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