Stress polishing of E-ELT segment at LAM: full-scale demonstrator status

Marie Laslandes; Nicolas Rousselet; Marc Ferrari; Emmanuel Hugot; Johan Floriot; Sébastien Vivès; Gérard Lemaitre; Jean François Carré; Marc Cayrel

doi:10.1117/12.896704

30 September 2011 Stress polishing of E-ELT segment at LAM: full-scale demonstrator status

Marie Laslandes, Nicolas Rousselet, Marc Ferrari, Emmanuel Hugot, Johan Floriot, Sébastien Vivès, Gérard Lemaitre, Jean François Carré, Marc Cayrel

Author Affiliations +

Proceedings Volume 8169, Optical Fabrication, Testing, and Metrology IV; 816903 (2011) https://doi.org/10.1117/12.896704
Event: SPIE Optical Systems Design, 2011, Marseille, France

Abstract

The Laboratoire d'Astrophysique de Marseille (LAM) is involved in the prototyping of a full scale demonstrator for stress polishing of segments for the European Extremely Large Telescope (E-ELT). Stress polishing method is developed at LAM since more than 40 years, and this mature technology has recently been used with success for VLT instruments. Stress polishing is now considered as a promising manufacturing method for mass production of large off axis mirrors, specifically for ELT segments. This powerful method, based on elasticity theory, allows the generation of super-smooth off-axis aspherics with a minimal amount of high spatial frequency ripples by spherically polishing a warped blank with a full-sized tool. Thanks to the simple spherical polishing, the operation time can be strongly reduced compared to the time-consuming sub-aperture tool methods of grinding and polishing. The goal is to rapidly converge to less than 1 micron RMS of optical quality on a circular blank which will be finally cut hexagonally and finished using Ion Beam Finishing. In this paper we will present the status of the demonstrator and the design of the warping harness prototype that must be able to precisely warp the circular blank.

Citation Download Citation

Marie Laslandes, Nicolas Rousselet, Marc Ferrari, Emmanuel Hugot, Johan Floriot, Sébastien Vivès, Gérard Lemaitre, Jean François Carré, and Marc Cayrel "Stress polishing of E-ELT segment at LAM: full-scale demonstrator status", Proc. SPIE 8169, Optical Fabrication, Testing, and Metrology IV, 816903 (30 September 2011); https://doi.org/10.1117/12.896704

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available