Enhancement of diamond machined RSA-Al501 surfaces for optical applications by process integrated Ion Beam Etching

• Applicants: Professor Dr. Thomas Arnold; Professor Dr.-Ing. Dirk Oberschmidt
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452333040

The overall objective of the project is the production of metal optics for the UV VIS range through a process chain consisting of ultra-precision machining and subsequent ion beam machining. The working hypothesis of the project is the assumption that the changes in the sub-surface caused by ultra-precision machining have an influence on the ion beam processes. The aim of the project is to gain fundamental knowledge about the material properties after machining with geometrically defined diamond tools in RSA-501 as well as their effects on ion beam-based smoothing and removal processes. From this, process strategies and parameters for shape correction and surface smoothing using ion beam machining in RSA-501 are derived. The generation of the continuous and discontinuous geometries by means of ultra-precision machining currently enables roughness values of the blaze flanks in the range Rq > 2nm. Through the knowledge gained in the project, it is expected that, especially through the investigations of the interaction of ion beam with the surface, roughness values below Rq < 0.5 nm [ARC18] with shape deviations < 2 nm can be realised. In the second funding period, it will be focused on improving the quality of structured surfaces. This includes the basic modelling of the type and characteristics of the change in the sub-surface zone, the establishment of a fundamental technological basis for machining the RSA alloys relevant to the different requirements, and the combination of both processes to achieve the overall goal.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Stefan Kühne