The glass ceramic ZERODUR is well known for its extremely low coefficient of thermal expansion making it one of the key materials for ultra-precision application such as IC and LCD Lithography, High-end Metrology, Aviation and space borne or ground based Astronomy. The steady growth of demand for more precision in those applications together with a growing number of precision systems and components is requesting the ability to on hand increase precision in manufacturing. Additionally, there is a need to increase production capacity of ZERODUR CNC machined products in parallel. This paper reports on the measures SCHOTT is realizing to feed the continuously increasing demand on high precision material and components. Next to a second melting tank additional capacity is going to be installed along the entire value stream of ZERODUR production. Features of new CNC machining capabilities in the two and four meter class will be reported allowing to provide tighter tolerance on mirror surface figure together with reduced sub surface damage in order to accelerate the polishing time. Examples are discussed such as the 4 m class secondary and tertiary mirrors for the ESO E-ELT. The new equipment will enable SCHOTT to light weight 4 m class mirror substrates for future space optics demand.

Date Published: 5 September 2017
PDF: 9 pages
Proc. SPIE 10401, Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems, 104010R (5 September 2017); doi: 10.1117/12.2274330

Published in SPIE Proceedings Vol. 10401:
Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems
Tony B. Hull; Dae Wook Kim; Pascal Hallibert, Editor(s)