Experimental and numerical investigation on shear banding during nanomachining of an amorphous glassy polymer.

Highlights • Nanomachining of glassy polymer is carried out below the depth of 200 nm. • Shear banding occurs when the depth of cut or cutting speed exceeds critical value. • Finite element analysis is conducted using a viscoplastic model accounting for adiabatic heating. • Adiabatic heating causes the formation of shear band in nanomachining of polymer. Abstract This paper discusses the shear banding phenomenon which took place during nanomachining of an amorphous glassy polymer. The nanomachining were carried out with varying machining conditions (depth of cut, machining speed), and the morphologies of the machined surfaces were characterized using atomic force microscopy. The experiments reveal the occurrence of shear band as the critical machining condition is reached. The shear banding was rationalized by the effect of adiabatic heating during machining. Finite element modelling of nanomachining was conducted using an existing elastic-viscoplastic model for this polymer, which accounts for the adiabatic heating due to plastic dissipation. The simulation was then compared with the experiment. It shows that the simulation can capture the main features of shear banding in nanomachining, indicating that the machining is controlled by a localized deformation mechanism. This work can be helpful in optimizing the processing parameters to improve the surface quality of optical products. Graphical abstract Image, graphical abstract [ABSTRACT FROM AUTHOR]