An experimental study of edge radius effect on cutting single crystal silicon

Abstract

According to the hypothesis of ductile machining, brittle materials undergo a transition from brittle to ductile mode once a critical undeformed chip thickness is reached. Below this threshold, the energy required to propagate cracks is believed to be larger than the energy required for plastic deformation, so that plastic deformation is the predominant mechanism of material removal in machining these materials in this mode. An experimental study is conducted using diamond cutting for machining single crystal silicon. Analysis of the machined surfaces under a scanning electron microscope (SEM) and an atomic force microscope (AFM) identifies the brittle region and the ductile region. The study shows that the effect of the cutting edge radius possesses a critical importance in the cutting operation. Experimental results of taper cutting show a substantial difference in surface topography with diamond cutting tools of 0°rake angle and an extreme negative rake angle. Cutting with a diamond cutting tool of 0°rake angle could be in a ductile mode if the undeformed chip thickness is less than a critical value, while a ductile mode cutting using the latter tool could not be found in various undeformed chip thicknesses.

Theoretical and experimental investigations of finish machining with a rounded edge tool

“…For example, Fang and Zhang [3] performed experimental investigations and reported that the tool edge radius causes an extreme negative rake angle in machining, and that the plastic deformation and plowing * Corresponding author. become dominant action rather than cutting.…”

Quality of silicon convex lenses fabricated by ultra-high precision diamond machining

“…The influence of tool geometry was investigated by Fang and Zhang [13]. They concluded that ductile machining can be achieved by using a diamond tool with a negative effective rake angle.…”

An experimental study on the machining characteristics in ductile-mode milling of BK-7 glass

“…Later studies established some strategic requirements concerning ductile-mode machining. Fang and Zhang [10] reported that edge radius should be at submicron level for fracture-free machining of brittle materials. It was reported by Cai et al [11] that brittle-ductile transition in machining of brittle materials occurs if the cutting tool edge radius is reduced to nanoscale and the undeformed chip thickness is smaller than the tool edge radius.…”