Journal of the European Optical Society - Rapid publications, Vol 11 (2016)

Robotic automation in computer controlled polishing

D. D. Walker, G. Yu, M. Bibby, C. Dunn, H. Li, H. Y. Wu, X. Zheng, P. Zhang


We first present a Case Study – the manufacture of 1.4 m prototype mirror-segments for the European Extremely Large Telescope, undertaken by the National Facility for Ultra Precision Surfaces, at the OpTIC facility operated by Glyndwr University. Scale-up to serial-manufacture demands delivery of a 1.4 m off-axis aspheric hexagonal segment with surface precision < 10 nm RMS every four days, compared with a typical year or more for an one-off part. This requires a radically-new approach to large optics fabrication, which will inevitably propagate into wider industrial optics. We report on how these ambitious requirements have stimulated an investigation into the synergy between robots and computer numerically controlled (‘CNC’) polishing machines for optical fabrication. The objective was not to assess which is superior. Rather, it was to understand for the first time their complementary properties, leading us to operate them together as a unit, integrated in hardware and software. Three key areas are reported. First is the novel use of robots to automate currently-manual operations on CNC polishing machines, to improve work-throughput, mitigate risk of damage to parts, and reduce dependence on highly-skilled staff. Second is the use of robots to pre-process surfaces prior to CNC polishing, to reduce total process time. The third draws the threads together, describing our vision of the automated manufacturing cell, where the operator interacts at cell rather than machine level. This promises to deliver a step-change in end-to-end manufacturing times and costs, compared with either platform used on its own or, indeed, the state-of-the-art used elsewhere.

© The Authors. All rights reserved. [DOI: 10.2971/jeos.2016.16005]

Full Text: PDF

Citation Details

Cite this article


R. Gilmozzi, and J. Spyromilio, ”The European Extremely Large Telescope (E-ELT),” The Messenger 127, 11–19 (2007).

A. Swat, ”ESO Prototype segment specification,” E-SPE-ESO-300- 0150 4, 1–33 (2009).

J. E. Nelson, and T. S. Mast, ”Construction of the Keck Observatory,” Proc. SPIE 1236, 47–55 (1990).

D. Walker, I. Baker, R. Evans, S. Hamidi, P. Harris, H. Li, W. Messelink, et al., ”Technologies for producing segments for extremely large telescopes,” Proc. SPIE 8126, 893360 (2011).

C. Gray, I. Baker, G. Davies, R. Evans, N. Field, T. Fox-Leonard, W. Messelink, et al., ”Fast manufacturing of E-ELT mirror segments using CNC polishing,” Proc. SPIE 8838, 2023475 (2013).

P. Comley, P. Morantz, P. Shore, and X. Tonnellier, ”Grinding metre-scale mirror segments for the E-ELT ground based telescope,” CIRP Ann-Manuf. Techn. 60, 379–382 (2011).

M. Cayrel, ”Specification for the supply by OpTIC of prototype segments of the E-ELT primary mirror,” E-SPE-ESO-300-0150 5, 1–36 (2013).

H. Chen, W. Sheng, N. Xi, M. Song, and Y. Chen, ”Automated robot trajectory planning for spray painting of free-form surfaces in automotive manufacturing,” Proceedings to the IEEE International Conference on Robotics and Automation, 450–455 (IEEE, Washington DC, 2002).

C. W. King, and M. Bibby, ”Development of a metrology workstation for full-aperture and sub-aperture stitching measurements,” Procedia CIRP 13, 359–364 (2014).

M. Bibby, and C. W. King, ”Development of an on-machine 3D texture analyser,” Adv. Mat. Res. 579, 338–347 (2012).

D. Walker, G. Yu, H. Li, W. Messelink, R. Evans, and A. Beaucamp, ”Edges in CNC polishing: from mirror-segments towards semiconductors, paper 1: edges on processing the global surface,” Opt. Express 20, 19787–19798 (2012).

M. R. Driels, Lt W. Swayze, and Lt S. Potter, ”Full-pose calibration of a robot manipulator using a coordinate measuring machine,” Int. J. Adv. Manuf. Tech. 8, 34–41 (1993).

J. Ji, L. Sun, and L. Yu, ”A new pose measuring and kinematics calibrating method for manipulators,” in Proceedings to the 2007 IEEE International Conference on Robotics and Automation, 4925–4930 (IEEE, Roma, 2007).

H. Alzarok, S. Fletcher, A. P. Longstaff, and A. Myers, ”Assessment of the positioning accuracy of a small articulated robot during machining operations,” in Proceedings to the Computing and Engineering Annual Researchers’ Conference 2013, 106–111 (University of Huddersfield, Huddersfield, 2013).

D. Walker, C. Dunn, G. Yu, M. Bibby, X. Zhenga, H. Y. Wu, H. Lia, et al., ”The role of robotics in computer controlled polishing of large and small optics,” Proc. SPIE 9575, 2189203 (2015).