Comley, PaulMorantz, PaulShore, PaulTonnellier, Xavier2011-08-192011-08-192011-04-21P. Comley, P. Morantz, P. Shore and X. Tonnellier, Grinding metre scale mirror segments for the E-ELT ground based telescope, CIRP Annals - Manufacturing Technology, Volume 60, Issue 1, 2011, Pages 379-382.0007-8506http://dx.doi.org/10.1016/j.cirp.2011.03.120http://dspace.lib.cranfield.ac.uk/handle/1826/5779The next generation of ground based telescopes require many hundreds of metre scale off-axis mirrors. In this paper the grinding of a 1.45m scale Zerodur® mirror segment for the European Extremely Large Telescope (E-ELT) is introduced. Employing an R-theta grinding mode with a multi stage grinding process material removal rates of up to 187.5mm3/s are achieved, whilst typically removing up to 1mm depth of material in total. Results show a RMS form error of <1μm, with subsurface damage <10μm, and a production cycle time under 2en-UKNOTICE: this is the author’s version of a work that was accepted for publication in CIRP Annals - Manufacturing Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in CIRP Annals - Manufacturing Technology, VOL 60, ISSUE 1, (2011) DOI: 10.1016/j.cirp.2011.03.120Article