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Graphical abstract Highlights • Surface generation mechanism is studied by MD and experiments. • Slipping processes during material deformation are visualized. • Smaller groove depth and width be generated in comparison to static plowing. • Average machining force is significantly smaller for dynamic plowing. Abstract Dynamic ploughing lithography based on atomic force microscope (AFM) is a promising technique for fabrication of nano structures and devices. This study investigates the material removal mechanism and surface generation in dynamic ploughing of single crystal copper by molecular dynamics (MD) simulations in addition to the experimental tests, and compares it with that of static ploughing lithography. It is found that the material removal in dynamic ploughing is mainly due to downwards and sidewards slipping of workpiece material on the {1 1 1} slip planes and the subsequent elastic recovery, whereas forwards and sidewards slipping account for the material removal in static ploughing. As a result, there is little chip formation in dynamic ploughing, while significant chip formation is observed for static ploughing in both simulations and experiments. In addition, this results in smaller groove depth and width for dynamic ploughing, allowing fabrication of nanostructures with smaller features. The slipping processes in both static and dynamic ploughing can be corresponded with the periodical variations of machining forces. The average machining force in dynamic ploughing is significantly smaller than that in static ploughing. This indicates the possibility of reducing the wear of AFM tip by employing dynamic ploughing lithography, since the tip wear is greatly influenced by the magnitude of machining force. These results reveal the mechanism of material removal and surface generation in dynamic ploughing lithography, which can be of useful reference for its practical application in nanomanufacturing. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Relationship between material removal mode and scratching direction is investigated. • A theoretical model is developed to relate machining depth with normal load. • An optimal machining direction is selected based on the quality of the grooves. Abstract The material removal state, which is closely related to machining quality, is an important factor in any machining process. During the machining using a non-rotational symmetric cutting tool, scratching direction manifests significant influence on the material removal state. In the present study, the relationship between material removal mode and scratching direction was investigated during the nanoscratching process on single crystal copper using an atomic force microscopy (AFM) tip. Considering the installation angle of the cantilever and the height of pile-up, a theoretical model was developed to relate machining depth with normal load for the machining of a single groove. Experimental results revealed that the theoretical normal load model was more suitable when materials were expelled in constant chip formation with small pile-ups. In addition, based on the scratching tests in different directions, the critical included cutting angle determined whether materials were expelled in chip formation or not. The height of pile-up was also influenced by the included cutting angle during the scratching in face-forward direction; however, during the machining in edge-forward direction, the distance between the cutting swept faces formed by the lateral and front edges determined the height of pile-up. Finally, an optimal machining direction is selected based on the quality of the machined grooves, which can be used in the potential application. [ABSTRACT FROM AUTHOR]