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2008
Conference Paper
Titel
Polishing-grinding - an innovation for high precision optics
Abstract
The technology of ELID-grinding was developed as an in-process dressing of the grinding wheel and the advantages are well known. This technique allows the continuous use of tools with the smallest grain sizes under stable grinding conditions. Yet little is known about the polishing principle that occurs during the employment of electro-chemical process of metal bonded grinding wheels. At the same time especially the use of grinding wheels with ferrous binding shows an additional aspect when grinding glass. The electrolytic reaction produces metal oxides, particularly iron oxides. These materials have a long history in the manufacturing process of glass lenses. Since early days glass was polished with metal oxides. However, while today CeO2 is meant to be state-of-the-art ferrous oxides known as rouge were used until few decades ago. Indeed, the iron oxides produced in the electrolytic process of ELID can have a special polishing effect on the components made of glass. For this reason Fraunhofer IPT is developing an Electrolytic Generated Polishing-Grinding (EGPG). As the polishing process of surfaces up to optical quality takes the biggest amount of time of the entire production chain, EGPG permits a considerable reduction of time and cost in producing of glass products with ultra precise optical surfaces. Especially in the manufacturing procedures of aspheric glass lenses production the conventional polishing steps contain enormous technological challenges and take up to 70 % of production time. At this point Polishing-Grinding offers the opportunity to integrate the polishing step into a grinding process. This will reduce the following polishing time or even make it redundant. In this paper the author presents and discusses different approaches of material removal mechanism which occur during Polishing-Grinding.
Author(s)