Effect of cutting edge radius on ductile-brittle transition in cutting of silicon-wafers

Abstract

Ductile mode cutting of silicon wafers can be achieved under certain cutting conditions and tool geometry. An experimental investigation of the critical undeformed chip thickness in relation to the cutting edge radius for the brittle-ductile transition of chip formation in cutting of silicon wafers is presented in this paper. Experimental tests for cutting of silicon wafers using diamond tools of different cutting edge radius at a range of undeformed chip thicknesses are conducted on an ultra precision lathe machine. Both ductile mode and brittle mode of chip formation processes are observed in the cutting tests. The results indicate that ductile cutting of silicon can be achieved under certain values of the undeformed chip thickness, which depend on the tool cutting edge radius. It is found that there is a critical value of undeformed chip thickness in cutting of silicon wafers beyond which the chip formation changes from ductile mode to brittle mode. The ductile-brittle transition of chip formation varies with the tool cutting edge radius. Within the range of cutting conditions in the present study, it has also been found that the larger the cutting edge radius, the larger the critical undeformed chip thickness for the ductile-brittle transition in the chip formation.