Freeform machining of ophthalmic toric lens mould using fast tool servo-assisted ultra-precision diamond turning process. Issue 1 (May 2021)

• Record Type: Journal Article
• Authors: Singh, Ishan Anand; S., Gopi Krishna; Reddy, T. Narendra; Vinod, Prakash
• Other Names: Balasubramaniam R. guest-editor.; Bukkapatnam Satish T. guest-editor.; Subbiah Sathyan guest-editor.; Rao Prahalada guest-editor.
• Is Part Of: Journal of micromanufacturing. Volume 4:Issue 1(2021)
• Page Start: 84
• Page End: 92
• Publication Date: 2021-05
• Subjects: Astigmatism lens mould -- toric lens mould -- fast tool servo -- diamond turning; Micromachining -- Periodicals; Microfabrication -- Periodicals; 670
• DOI: 10.1177/2516598420939745
• Languages: English
• ISSNs: 2516-5984

Abstract

This research aims to establish a methodology for machining of toric lenses, using fast tool servo-assisted single point diamond turning and to assess the generated surface for its characteristics. Using the established mathematical model, toric surface is explained to understand the geometry and to generate the parameters required for fast tool servo machining. A toric surface with a major diameter of 18.93 mm and a minor diameter of 15.12 mm has been cut on the intelligent ultra-precision turning machine (iUPTM). The surface profile and surface roughness were measured. After analysing the measurement data of the machined surface, on two perpendicular axes of the toric lens, form accuracy of 0.49 µm peak-to-valley (PV), and surface roughness of 12 nm in Ra, 4–8 nm in Sa are obtained. From the experimental results obtained, it can be concluded that the proposed method is a reasonable alternative for manufacturing toric lens mould.