International Journal of Extreme Manufacturing, Volume. 2, Issue 4, 45301(2020)

Design of a motorised plasma delivery system for ultra-precision large optical fabrication

Hui Zhou1... Adam Bennett1, Marco Castelli2, Renaud Jourdain1, Jiang Guo3 and Nan Yu4,* |Show fewer author(s)
Author Affiliations
  • 1Surface Engineering and Precision Institute, Cranfield University, Bedford, United Kingdom
  • 2Manufacturing Technology Centre (MTC), Coventry, United Kingdom
  • 3Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian, People’s Republic of China
  • 4Centre of Micro/Nano Manufacturing Technology, University College Dublin, Dublin, Ireland
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    A unique plasma figuring (PF) process was created and demonstrated at Cranfield University for manufacturing extremely large telescopes. The atmospheric pressure processing is faster and more cost-effective than other finishing processes; thus, providing an important alternative for large optical surfaces. The industrial scale manufacturing of thousands of ultra-precision metre-scale optics requires a robust PF machine: this requirement is achieved by making the plasma delivery system (PDS) performance repeatable. In this study, a dedicated PDS for large optical manufacturing was proposed to meet the industrial requirement. The PDS is based on an L-type radiofrequency (RF) network, a power supply, and an inductively coupled plasma torch. However, the complexities of these technologies require an in depth understanding of the integrated components that from the PDS. A smart control system for the modified PDS was created. This novel control system aims to make the characterization process deterministic: by automating the tuning of critical electrical components in the RF network, which is achieved by the use of in-line metrology. This paper describes the main design aspects. The PDS was tested with a good correlation between capacitance and RF frequencies. The robust PDS design enables a stable discharge of plasma with a low deviation of RF signals during the total 15 hours’ test.

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    Hui Zhou, Adam Bennett, Marco Castelli, Renaud Jourdain, Jiang Guo, Nan Yu. Design of a motorised plasma delivery system for ultra-precision large optical fabrication[J]. International Journal of Extreme Manufacturing, 2020, 2(4): 45301

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    Paper Information

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    Received: Apr. 2, 2020

    Accepted: --

    Published Online: Apr. 16, 2021

    The Author Email: Yu Nan (nan.yu@ucd.ie)

    DOI:10.1088/2631-7990/abab49

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