Table 3
Average cutting force and frictional coefficient with different undeformed chip thickness
Cutting direction	Cutting depth (nm)	Tangential force (nN)	Normal force (nN)	Frictional coefficient
on (010) surface	1	315.3	647.5	0.487
on (111) surface	1	342.5	659.1	0.520
on (010) surface	2	550.7	1056.9	0.521
on (111) surface	2	592.4	1058.5	0.560
on (010) surface	3	778.0	1360.4	0.572
on (111) surface	3	850.4	1372.8	0.619

Lai et al. Nanoscale Research Letters 2013 8:13   doi:10.1186/1556-276X-8-13