In situ experimental study on material removal behaviour of single-crystal silicon in nanocutting

Ductile-mode removal of single-crystal silicon can be achieved by strictly controlling the cutting parameters, which significantly affects the machining efficiency. To improve the surface quality without reducing the machining efficiency, nanocutting experiments were performed to study the material removal behaviour using a specially designed nanocutting platform with a scanning electron microscope (SEM). Diamond tools with different edge radii were fabricated by focused ion beam (FIB) technology. The initiation and propagation of microcracks were observed online by an SEM to analyse the material removal behaviour of single-crystal silicon in the brittle mode. The effects of the crystal orientation and tool edge radius on the critical thickness of the brittle-ductile transition were investigated. Additionally, in the ductile mode, the influence of the tool edge radius on the minimum cutting thickness (MCT) was analysed. It was determined that the ratio of the MCT to the tool edge radius was 0.32-0.50, regardless of the tool edge radius. This in situ experimental study can provide a direct verification for the material removal behaviour in nanocutting.