Research on mechanism of nanoscale cutting with arc trajectory for monocrystalline silicon based on molecular dynamics simulation

Q Kang and XD Fang and L Sun and JJ Ding and ZD Jiang, COMPUTATIONAL MATERIALS SCIENCE, 170, UNSP 109175 (2019).

DOI: 10.1016/j.commatsci.2019.109175

Movement trajectory of diamond tool during an ultra-precision cutting may be nonlinear due to external vibrations. Hence, we investigate nanoscale cutting of monocrystalline silicon using molecular dynamics simulation when the diamond tool trajectory contains an arc segment. Surface morphology, atomic displacement, radial distribution function, coordination values, common neighbor analysis, temperature variation and distribution of von Mises stress and hydrostatic stress are studied by changing the arc radius of tool path. An optimal surface integrity for the workpieces is obtained when the arc radius is 30 angstrom. Displacement vector analysis shows that the atoms at the initial position between the diamond tool and the workpiece have relatively large displacement. Furthermore, cutting distance has great influence on radial distribution function and atomic coordination values. Dislocation analysis indicates that the subsurface of workpiece with the arc radius of 30 angstrom is the smoothest, while temperature analysis reveals that only the maximum temperature of this workpiece exceeds 1000 K. Finally, the stress analysis indicates that the average hydrostatic stress decreases before increasing with the arc radius. For comparison, the average von Mises stress increases gradually. In addition, peak value of the two average stresses resides at the middle and the end of the arc, respectively. The curve trajectory of the tool results in the concentration of the hydrostatic stress and the von Mises stress in the local region of workpiece subsurface.

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