Γ	rake angle
A	clearance angle
vc	cutting velocity
d, dmin	cutting depth
Fc	tangential force
Ft	contact force
R, Rmax, Rmin	resultant cutting force
S, Smax, Smin	shear force
R	cutting edge radius
P	ploughing force
Fn	forces across the shear plane
Fs	forces along the shear plane
Ff	frictional force
N	normal force
Θ	shear angle
d 1	chip thickness
μtc	the friction coefficient of the tool–chip contact surface
μtw	the friction coefficient of the tool–workpiece contact surface
μ, COF	the friction coefficient in the cutting zone
Fp	contact zone cutting force
Np	contact zone normal force
Rt	resultant force in the transverse direction
Pt	ploughing force in the transverse direction
Rc	resultant force in the cutting direction
Pc	ploughing force in the cutting direction
A	shear zone area
w 1	shear zone width
w 2	shear zone length
l	cutting path
AE	acoustic emission signal value