In the eyewear business, lenses are part of your daily operations. You measure them, select them, and rely on them. While you may know common specs like refractive index, Abbe value, and weight, have you ever wondered how lenses are actually made? What steps turn liquid materials into precise optical products? At ReOptical, a professional eyeglass lens manufacturer, we’re opening the doors to our production line to show you how the optical lens manufacturing process really works.
ReOptical produces high-quality eyeglass lenses using a detailed 12-step manufacturing process designed for accuracy, consistency, and efficiency.
Step 1: Preparing Lens Materials
Our production begins in the raw material area, where monomers are blended with additives. Depending on the lens type, we use different base materials — CR-39 for 1.499 index, NK-55 for 1.56, or photochromic materials for color-changing lenses. Additives include UV-blockers, pigments, antioxidants, and flow stabilizers. The mixture is filtered, vacuum-treated, and degassed, then transferred into storage containers. After stirring, the liquid is poured into casting tanks for further use.
Step 2: Mold Setup
We use specially designed glass molds due to their high heat resistance and dimensional stability. There are two mold assembly methods: one involves reusable rings to clamp the mold pair, and the other uses a one-time sealing tape applied by machinery. Each mold undergoes a deep cleaning procedure before assembly to ensure defect-free casting.
Step 3: Monomer Injection
A polymer mix consisting of CR-39, initiators, mold-release agents, and UV-absorbing agents is prepared to the right viscosity. This liquid is carefully poured into molds without introducing bubbles or overflow. Experienced technicians manage the process to ensure precision.
Step 4: First Heat Curing
The filled molds are placed into a thermal chamber where the polymer slowly changes into a solid transparent lens. This process can take over 20 hours and involves strict temperature control based on lens material and final optical properties.
Step 5: Lens Separation
After the initial curing, lenses are separated from their molds using compressed air. The sealing elements are removed—recyclable rings or discarded tape—followed by cleaning and basic shaping of the newly formed lens.
Step 6: Edge Processing
Rough lens edges are smoothed using specialized edging machines. Before cutting, lenses are dipped in a protective solution to reduce the risk of damage. After trimming, lenses are inspected and cleaned.
Step 7: Deep Cleaning Stage
Lenses are cleaned multiple times to eliminate any residue from the polymerization phase. A series of ultrasonic cleaning tanks ensure all surfaces are spotless. Once cleaned, lenses proceed to post-curing.
Step 8: Second Heat Treatment
This second thermal cycle removes remaining internal stress and enhances the surface durability of the lens. Proper timing and heat balance are essential to improve the mechanical properties of the lens before inspection.
Step 9: Base Lens Inspection
Each base lens is tested for optical clarity and structure. Acetone is used to test surface stability, while instruments measure strength, thickness, power, and center alignment. Only lenses that meet quality criteria move to the next step.
Step 10: Surface Conditioning
To prepare for the hard coating, lenses are thoroughly washed and slightly roughened. This improves adhesion of the hard coating liquid. The steps include washing, drying, applying the hard layer, and final surface preparation.
Step 11: Lens Coating
Lenses are placed in a vacuum coating machine where thin layers of high-refractive metal oxides are applied via ion sputtering. This advanced coating method improves light transmission (up to 97%) and gives the lenses a premium appearance. Our facility uses semi-automatic Korean machines monitored closely by experienced staff.
Step 12: Final Coating Check
The coated lenses undergo durability testing using a saltwater boiling process. In this test, lenses are repeatedly exposed to heated saltwater to check for peeling or cracks in the coating. Any item that fails is reprocessed to maintain consistent quality.
At ReOptical, every lens goes through this 12-step optical lens manufacturing process, ensuring that the final product meets global standards. Our process is the result of years of refinement, advanced technology, and skilled craftsmanship. We are proud to deliver high-precision lenses trusted by professionals across the international eyewear market.
Looking for a dependable lens manufacturing partner for your business? Contact us today for a customized quote or more information. We’re here to support your wholesale or branded optical product needs.
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