Micro-optical fabrication by ultraprecision diamond machining and precision molding

Abstract

Ultraprecision diamond machining and high volume molding for affordable high precision high performance optical elements are becoming a viable process in optical industry for low cost high quality microoptical component manufacturing. In this process, first high precision microoptical molds are fabricated using ultraprecision single point diamond machining followed by high volume production methods such as compression or injection molding. In the last two decades, there have been steady improvements in ultraprecision machine design and performance, particularly with the introduction of both slow tool and fast tool servo. Today optical molds, including freeform surfaces and microlens arrays, are routinely diamond machined to final finish without post machining polishing. For consumers, compression molding or injection molding provide efficient and high quality optics at extremely low cost. In this paper, first ultraprecision machine design and machining processes such as slow tool and fast too servo are described then both compression molding and injection molding of polymer optics are discussed. To implement precision optical manufacturing by molding, numerical modeling can be included in the future as a critical part of the manufacturing process to ensure high product quality.

Key words： ultraprecision machining; slow tool servo; fast tool servo; compression molding; injection molding; microlens arrays; optical fabrication

Acknowledgements

The work was partially based on work supported by an SBIR Phase I project from the National Science Foundation of the US (Grant No. 1315009), an SBIR Phase II project from the National Science Foundation of the US (Grant No. 1456291), and a research grant from the National Science Foundation of the US (Grant No. 1537212); Any opinions, findings, and conclusions or recommendations expressed in this article were those of the authors and do not necessarily reflect the views of the National Science Foundation of the US. The ISO 2.25 high-speed spindle used in this research was provided by Professional Instruments Inc. (www.airbearings.com). Authors also express sincere gratitude to Cedric Sze for some of the photos used in this publication.

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