Advances in ZERODUR? manufacturing for space and ground based telescopes

摘要

ZERODUR? is utilized in many ultra-precision applications such as IC and LCD Lithography, High-end Metrology, Aviation and space born or ground based Astronomy. Glass ceramics exhibit an extremely low coefficient of thermal expansion (CTE) together with an excellent homogeneity of CTE. Currently, the material demand of those ZERODUR? applications is continuously growing. In parallel, CNC machined parts are getting more and more complex and require more advanced machining capabilities. This paper reports on the actions SCHOTT is taking to fulfill the increasing demand on high precision material and components. SCHOTT increased capacity along the entire value stream of ZERODUR? production, starting from melting up through CNC machining. New CNC machines, together with process improvements, establish a new set of capabilities for up to four-meter-class substrates. Results are reported, demonstrating tighter tolerance on mirror surface figure together with reduced sub surface damage for accelerated polishing. The new equipment will enable SCHOTT to lightweight 4 m class mirror substrates for future space optics as well as serial production of smaller segments for larger diameter telescopes.