Zero-waste manufacturing of ophthalmic lenses by direct Fluidic Shaping in arbitrary domains
The conventional manufacturing of ophthalmic lenses is an inefficient subtractive process where up to 97% of the material is discarded through grinding, polishing, and edging. Fluidic Shaping has emerged as a powerful alternative, utilizing surface tension to form optical-quality surfaces. While the approach enabled the creation of ophthalmic lenses without grinding or polishing, it was limited to lenses with a circular or elliptical footprint and still required the wasteful edging process to fit the lenses into the eyewear rims. Here, the Cookie Cutter algorithm is introduced, generalizing the Fluidic Shaping approach to be applicable to arbitrary domains, thus eliminating all subtractive processes. This mathematical framework calculates the unique varying edge-height required for a boundary frame, allowing a liquid polymer to naturally settle into a target spherocylindrical prescription within an arbitrary rim footprint. By utilizing neutral buoyancy to negate gravity, the liquid polymer is shaped solely by surface tension and subsequently cured, resulting in a lens that fits directly into commercial eyewear rims without any mechanical post-processing. The method is validated experimentally, demonstrating the fabrication of lenses compatible with standard eyewear rims. This approach represents a complete additive manufacturing solution, enabling end-to-end zero-waste production of prescription eyeglasses.