SUNConferences, COMA '13

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Ultra-High Precision Machining of Modified High Strength Aluminium for Optical Mould Inserts
Khaled Abou-El-Hossein, Johannes Neethling, Oluwole Olufayo

Last modified: 2013-08-20


Traditional high strength aluminium grades such as AA6061 have been used in the high-precision industry to make components with good optical surface quality. AA6061 has become a successful material suitable for optics applications because of its increased strength and excellent thermal stability. However, when used as a mould material for injection of plastic optics AA6061 imposes some difficulties when ultra-high precision machined with diamond tools. This includes the difficulty in producing ultra-fine finishes of the machined surface which is a critical quality of optical mould inserts. Recently, a modified grade of AA6061 has been used in optics applications. This grade (RSA905) which is produced by rapid solidification demonstrates excellent optical characteristics. Surface finish of RSA905 when diamond machined is noticeably finer than that of AA6061 thanks to the fine microstructure and precisely controlled composition of the material. This study investigates the quality of ultra-high precision machined optical convex surfaces having a big curvature radius. The effect of different machining strategies and parameters are discussed in this paper.

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