NanoTooling

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Cost effective and scalable manufacturing techniques are required to integrate components with nano scale features into products, and thus to broaden the range of applications where nanotechnology-based devices are utilised. To address these needs, the research community has developed and is still investigating process chains that represent production platforms for serial manufacture of nano structured components. The aim is to combine in these chains the capabilities of master-making methods with those of high throughput replication technologies such as thermal or UV imprinting or micro injection moulding. To fabricate the necessary nano structured replication moulds, most process chains employ lithography-based pattern transfer techniques, and more recently direct write processes, e.g. Focused Ion Beam (FIB) machining. A common characteristic of all these master making technologies is that they rely on capital intensive equipment and necessitate particular operating temperatures or vacuum conditions. The high capital investment needed to acquire, operate and maintain such equipment represents a major obstacle in many nanotechnology application areas. As a result, this could hinder the development of new or improved nanotechnology-enabled products. For this reason, it is desirable to develop alternative process chains that incorporate widely used and relatively simple master making techniques for the fabrication of nano-structured replication moulds. Consequently, such process chains will enable the rapid and cost effective replication of nano structured components. One of the candidate technologies for the fabrication of such replication masters is the Atomic Force Microscopy (AFM) scratching process, as it allows material on the surface of a sample to be moved or removed at the nano scale. Due to the fact that the technique is relatively simple and AFM instruments are widespread in research laboratories, such an approach could offer a fast and cost-effective route for the fabrication of nano structured masters. Recent experimental studies have demonstrated the potential of the AFM scratching process to prepare replication moulds in relatively soft materials, and thus to produce small batches of nano structured polymer components.In order to make this promising technology economically viable, it is important to ensure that it can be applied on suitable master materials for the medium to large series production of polymer parts. Unfortunately, the crystalline structure of engineering materials commonly employed for such replication masters at the macro scale has a significant influence on the machining conditions at the nano scale. In particular, non-homogenous cutting conditions occur as the tip of an AFM cantilever moves across different grains. Thus, to produce nano structures reliably and accurately with this technology, it is necessary to adjust continuously the AFM scratching conditions to the materials' microstructure. Regrettably, no suitable models exist to describe and simulate this nanometric cutting process that take into account the microstructure of multiphase materials and its effects on the processing conditions.In this context, the proposed research programme will advance our understanding of this atomic level cutting process by modelling the physical phenomena that govern the mechanical interaction between the tip of an AFM cantilever and a workpiece material. The contribution to knowledge that is expected to result from this fundamental research will permit better control of the process when it is applied to produce nano structures in a broad range of materials, especially metals.