Effect of tool edge radius on material removal mechanism of single-crystal silicon: Numerical and experimental study

摘要

As a significant mean of ultra-precision machining technology, nanometric cutting plays an crucial role in the field of nano-manufacturing. Owing to the size effect at the nanoscale, the tool edge radius has a remarkable effect on the material removal mechanism. In this work, the material removal mechanism of single-crystal silicon is investigated both numerically and experimentally. Nanometric cutting simulations via molecular dynamic (MD) approach are firstly conducted to machine the specimen using diamond tools with different edge radii of 10, 20, 40 nm, respectively. The variations of atomic displacement vectors are analysed to study the material flow during nanometric cutting. On this basis, the minimum cutting thickness (MCT) of single-crystal silicon is deeply studied by labeling and tracing the silicon atoms. It is determined that the MCT strongly depends on the tool edge radius, and the ratio of the MCT to the tool edge radius is always between 0.25 and 0.4. Then, the material removal behavior is studied through the chip structure to distinguish the shear and extrusion. The effect of the tool edge radius on the cutting force is investigated as well. Ultimately, using a specially designed cutting device, nanometric cutting tests are performed to verify the MD simulation results. It indicates that the experimental results are in good agreement with the MD simulation results.