Due to the difficulty of measurement and evaluation of machined micron/nanometer-scale V-shaped groove

a single-point diamond turning was employed to machine the V-shaped groove of optic glass in micron/nanometer-scale and then a non-contact laser measure technology was used to analyze the topography of machined V-shaped groove. The aim is to analyze the micron/nanometer-scale machinability of V-shaped groove and find out the evaluation method for its machining precision. First

brittle/ductile mode cutting of V-shaped groove was conducted by using a single-point diamond turning. Then

the machined V-shaped groove was measured by 3D laser meter and then by using the measured data points

the evaluation mode of form error PV and tip arc-radius of V-shaped groove was established. Finally

the effect of sub-micron-scale cutting depth was investigated on the form error PV and the tip arc-radius. The results show that there exists a critical cutting depth transferred from brittle mode cutting to ductile mode cutting in sub-micron-scale space. In ductile mode cutting

the diamond tool tip can be replicated to the workpiece

producing the sub-micron-scale V-shaped groove with the cutting depth of 0.386μm and less

the form error PV of 0.103μm and the tip arc-radius of 0.182μm. In addition

the form error PV of V-shaped groove may maintain a stable value in ductile mode cutting

but greatly increased with the increase of cutting depth in brittle mode cutting; on decreasing the cutting depth

the tip arc-radius decreases in ductile mode cutting and also is reduced to critical borderline and less for the formation of V-shaped groove. It is concluded that the form error PV and the tip arc-radius can be employed to evaluate the machining precision and micro-scale of V-shaped groove by processing 3D data derived from non-contact laser measurement.