Simulation Analysis and Experiment Study of Nanocutting with AFM Probe on the Surface of Sapphire Substrate by Using Three Dimensional Quasi-steady Molecular Statics Nanocutting Model

摘要

The three-dimensional quasi-steady molecular statics nanocutting model is used by this paper to carry out simulation analysis of nanocutting of sapphire in order to explore the effects of conical tools with different tip radii of probe and straight-line cutting at different cutting depths, on cutting force. Meanwhile, this paper uses a cutting tool of atomic force microscopy (AFM) with a probe tip similar to a semisphere to conduct nanocutting experiment of sapphire substrate. Furthermore, from the experimental results of nanocutting sapphire substrate, this paper in-novatively proposes the theoretical model and equation that the specific down force energy (SDFE) during nanocutting by using AFM probe as the nanocutting tool, is approximately a constant value. This paper uses three-dimensional quasi-steady molecular statics nanocutting model to simulate calculation and obtain nanocutting down force. It is compared with the down force calculated by SDFE theoretical equation proposed for verification. As a result, the down force obtained by the paper's simulation is very close to the down force calculated by SDFE theory. Therefore, it can be verify that the three-dimensional quasi-steady molecular statics nanocutting theoretical model used by this paper is feasible. The SDFE proposed by this paper is defined as equating to down force energy dividing the removed volume of down press of the workpiece by the AFM probe. From the experimental data and the calculation results, it is found that the values of SDFE under different down force actions are almost close to a constant value. The three-dimensional quasi-steady molecular statics nanocutting sapphire workpiece model is to find the trajectory of each atom of the sapphire workpiecs being cut whenever the diamond cutter goes forward one step. It uses the optimization search method to solve the force equilibrium equation of the Morse force in the X, Y and Z directions when each atom moves a small distance, so as to find the new movement position of each atom, and step by step calculates the behavior during cutting.