Adhesion and friction in single asperity contact

In the modern era, many mechanical systems require more stringent requirements in terms of performance and reliability. The applications of these systems can be found in medical instrumentation, electron microscopes, lithography systems, as well as in aviation and space applications. Instruments like Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM), Scanning Tunnelling Microscope (STM) and many others enable us to perform experiments on an atomic scale. The mechanical systems in these instruments require high reliability and accurate performance. On the other hand, the revolution in the semiconductor industry calls for more rigorous requirements for the machines in order to manufacture smaller and smaller structures accurately. Similarly, the increasing demand of developing Micro Electro Mechanical Systems (MEMS) and Nano Electro Mechanical Systems (NEMS) forces the designers and researchers to think of those phenomena that are not important on macro scale. One of the important building blocks of these scientific instruments and industrial machines is the positioning mechanism. These mechanisms are used to manoeuvre the samples or products precisely and accurately in the order of a few nanometres. Therefore, achieving the precision and accuracy in positioning in the order of a few nanometres in these machines is an important target for designers and control engineers. The adhesion and friction behaviour of a single asperity contact is important to understand the overall adhesion and friction behaviour of surfaces in contact (e.g. in positioning mechanisms). Therefore, this study is focused on developing adhesion and friction models for a single asperity contact and validating them through experiments. A dedicated vacuum-based adhesion and friction tester was developed and the newly developed adhesion and friction models were verified for multiple number of material interfaces.