Ophthalmic Lenses

Traditional subtractive manufacturing has been used since the ancient Egyptians. The process used for making ophthalmic lenses has been improved significantly. The fundamental principle for manufacturing an ophthalmic lens has however remained the same.

Traditionally, a lens blank is created in a large manufacturing plant. The blank is shipped to the ophthalmic lab where it is stocked until required. When a certain lens prescription is prescribed for a patient, the appropriate blank is selected from a large inventory of blanks and the finishing process begins. Excess materials are cut away in several steps, to create the final shape and the resulting lens is polished to obtain a smooth surface. The process requires many manual handling steps and more than 10 machine processing steps.

Legacy Ophthalmic Lens Manufacturing Process

Around 80% of original materials are wasted in the cutting (grinding) process. Some of the used material in subtractive manufacturing can be re-used, such as the heavy metal alloy block that holds the lens during processing in the grinder and polisher. Subtractive manufacturing results in stockpiles of inventory and low yield. 

Additive manufacturing

The way of the future for manufacturing ophthalmic lenses is 3D printing technology which is a development that has come to maturity in very recent times. It has taken manufacturing to a new level in many industries by combining unlimited customization with large volumes when required. Where traditional manufacturing technology is focused on large volumes of identical products, 3D printing allows individual products, in volume.

3D printing has disrupted many industries by removing the requirements for stocking large inventories of products, allowing customization to individual needs. It has replaced or at least complemented conventional processing technology and has removed bottle-necks in fabrication.
Currently, many different materials can be 3D printed for applications in industries such as automotive, aerospace and even spectacle frames. An elusive application has been ophthalmic lenses, because of the requirements in transparency, surface smoothness, and accuracy of refraction.

In contrast to subtractive manufacturing technologies, a material is added to create a lens. 3D printing reduces industry expenses by combining efficiency and flexibility in the production flow. There is no need for stocking blanks, stock picking, blocking, taping, grinding, polishing, marking, de-blocking and de-taping. Multiple steps of traditional subtractive manufacturing technology can now be replaced with a single step: 3D printing the ophthalmic lens.

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