
210 CHAPTER 7 Micro- and nanomachining
found that for single crystal metals σ
S
is independent of τ
S
when plastics such as cel-
luloid are cut. In general, if a small amount of compressibility is involved, yielding
will occur when the von Mises criterion reaches a certain value.
However, based on the results of Table 7.1, the role of compressive stress on shear
stress on the shear plane in steady-state metal cutting is substantial. The fact there is
no outward sign of voids or porosity in steady-state chip formation of a ductile metal
during cutting, yet there is a substantial inuence of normal stress on shear stress
on the shear plane, represents ...