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

用含磨料的流体射流抛光为光学表面的精加工提供了各种可能性和优点。通过改变工艺，可以满足不同材料特性、所需表面粗糙度和形状精度等挑战。在这方面，与常用的磨料如氧化铈或SiC相比，金刚石颗粒作为磨料被证明具有更高的效率。由于机床的限制，迄今为止还不可能进行广泛的测试。为了科学地研究金刚石颗粒流体喷射抛光，必须将基础实验与数值模拟相结合，以确定其控制机制。本研究拟建立一个试验台，该试验台提供一个稳定的流体射流，该射流加载金刚石磨料到一个可移动的参考表面上。应通过适当的计量系统监测发生在射流以及冲击区和排放区的事故，并通过生成的表面形貌将其与材料去除相关联。通过数值建模和模拟，描述了整个流体运动以及单个颗粒相互作用以及与材料相互作用的行为，并与实验结果进行了验证。最后，将基本原理转化为真实的过程，以验证所开发的模型。该研究项目的科学挑战在于确定主导材料去除的基本机制，以及参数对这些机制的影响的揭示。此外，数值模拟方法的选择和过程固有边界条件的考虑是最高优先级的建模过程真实的真实的条件，以了解在最小尺度上的主要事件。

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.