Engineered Grinding Wheels - Precision grinding of optical glasses

• Applicant: Professor Dr.-Ing. Ekkard Brinksmeier
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: from 2007 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 42225879

Defined dressed, coarse-grained, single layered, metal bonded diamond grinding wheels, so called Engineered Grinding Wheels, with uniform abrasive grain protrusion heights and flattened grains are suitable for ultra-precision grinding of optical glasses. Experiments on BK7 and SF57 glass show that the cutting mechanisms turn into ductile removal and optical surfaces with surface roughness of about Sa = 20 nm are achievable. Compared with usually used fine-grained, resin-bonded diamond grinding wheels Engineered Grinding Wheels exhibit a high wear resistance. Therefore periodically dressing cycles can be significantly reduced and an economical application of ultra-precision grinding of large optical workpieces is feasible. Thus, Engineered Grinding Wheels are an economic and technological alternative to conventional fine-grained diamond grinding wheels.To introduce Engineered Grinding Wheels in industrial application, however, further basic questions have to be clarified. First, knowledge about the generation of the sub-surface damages in the sub-surface zone of the optical glasses is one major scientific interest. Further, possible macro- and microscopic wear mechanisms of the diamond grains, which are introduced by the grinding process, but also by the conditioning process have to be identified. The analysis of the sub-surface zone of the ground glass and the understanding of the wear mechanisms of the diamond grains are essential in order to enable the application of these novel diamond wheels for grinding of large glass surfaces.

• DFG Programme: Research Grants