Modelling the surface generation process during AFM probe-based machining: simulation and experimental validation

The controlled removal of material conducted with the tip of an atomic force microscope (AFM) probe is a technique that has started gaining increased attention in recent years within the micro and nano manufacturing research community. The attractive characteristics of this process are that it is relatively simple to implement and low-cost compared with vacuum-based lithography techniques for micro and nano fabrication. However, similarly to any machining process, the resulting surface finish of features cut with an AFM probe can be critical. In this context, the focus of the paper is on the development and validation of a novel analytical model for predicting the floor surface roughness induced by AFM probe-based machining when generating cavities composed of linear parallel grooves. In addition to kinematic parameters, the proposed model takes into account the minimum chip thickness and elastic recovery associated with each phase present within the microstructure of a workpiece. The implementation of the model was carried out and its performance tested when processing a dual phase brass alloy using an AFM nano-indentation probe. A relatively good agreement was achieved between the analytical and experimental results with an average prediction error of 21% when assessing the arithmetic average roughness, Ra.