Removal mechanisms during fluid jet polishing of amorphous materials with diamond particles

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Polishing with an abrasive-laden fluid jet offers various possibilities and advantages for finishing of optical surfaces. By varying the process, challenges like varying material behaviour, required surface roughness and form accuracy can be met. In this regard, diamond particles as abrasives are attested a higher efficiency compared to commonly used abrasives like cerium oxide or SiC. Because of machine tool restrictions a wide testing has not been possible so far. To investigate fluid jet polishing with diamond particles scientifically, it is essential to connect basic experiments with numerical simulations to identify the governing mechanisms. For this research project, a test stand is to be developed, which supplies a steady fluid jet which is loaded with diamond abrasives onto a movable reference surface. Incidents which take place in the jet as well as in the impact zone and drain zone shall be monitored by appropriate metrology systems and correlated to the material removal via the generated surface topography. By means of numerical modeling and simulations the entire fluid motion as well as the behavior of single particles, in interactions with each other as well as with the material, are described and verified with respect to the experimental results. Finally, the basic principles shall be transferred to a real process with the aim to validate the developed models. The scientific challenges of this research project lie in the identification of the fundamental mechanisms, which dominate the material removal, and the revelationof the influence of the parameters on these mechanisms. Furthermore, the choice of methods for the numerical simulations and the consideration of process inherent boundary conditions are of highest priority for modeling the process true to the real conditions to understand the principle incidents on the smallest scale.