Ductile cutting of tungsten carbide

Abstract

Tungsten carbide as a super hard and high wear-resistant material has been used widely in industry. The common method for producing tungsten carbide components is by powder metallurgy technology. However, for small quantity production, such as product prototyping, this method is obviously too costly and time consuming. It is expected to make the prototypes by material removal process, such as cutting, if the ductile cutting of tungsten carbide can be achieved. In this paper, a theoretical and experimental study on the ductile cutting of tungsten carbide is presented. Theoretical analyses are given on the characteristics of tungsten carbide as functions of temperature and on the critical conditions for ductile mode chip formation in the cutting of tungsten carbide. An energy model for ductile chip formation in the cutting of tungsten carbide is developed, in which the critical undeformed chip thickness for ductile chip formation in the cutting of tungsten carbide can be predicted from the workpiece material characteristics, tool geometry and cutting conditions. The model is verified with experimental results from the cutting of tungsten carbide on a CNC lathe using CBN tools. The machined workpiece surfaces and their topographic details are examined using a scanning electron microscope (SEM) and an optical measurement inspection system (OMIS). The depth of cut at the transition region of the machined groove is measured using a surface profiler. It is shown that the predicted results for the critical undeformed chip thickness corresponding to ductile cutting agree well with the experimental results.