Effect of crystallographic orientation on wear of diamond tools for nano-scale ductile cutting of silicon

Wear in diamond tools is a crucial factor in ultra-precision machining. However, as is well known, single crystal diamond possesses strong anisotropy. Its mechanical and physical properties vary with crystallographic orientation. In this study, tool wear investigation was carried out on nano-scale ductile cutting of silicon using an ultra-precision lathe with single crystal diamond tools. The wear characteristics of single point diamond tools and the effect of diamond crystallographic orientation were investigated. Experimental results indicate that gradual wear occurred mainly on the flank face of the tool. A very smooth wear mark on the rake face was also seen. The machining data show that wear resistance of the tool and tool life were greater when the crystallographic orientation of the rake face was {110} than when it was {100} or {111}. The thrust force on the diamond tool was lower when the rake face crystallographic orientation was {110} than when it was some other orientation. For all the crystallographic orientations studied in the diamond tools, gradual tool flank wear had no significant effect on the surface roughness of machined silicon work material. (C) 2004 Elsevier B.V. All rights reserved.