Your source for the latest on sustainability, technology and innovation.

Your source for the latest on sustainability, technology and innovation.

How Sunglasses Are Made

Sunglasses not only protect your eyes from those harmful UV rays, but they’ve also become an iconic fashion statement piece. And, in these blazing summer months, you couldn’t be more grateful for these little accessories which allow you to avoid having to squint and cover your eyes during these sunny afternoons. But how are these eye-opening accessories made?

Tomorrow's World Today Sunglasses 1

When making sunglasses, first you start with the frames. A steel mold is built to mimic the desired shape of the frames. Next, cellulose-acetate (a plastic material) is made into sheets that are slightly wider than the frames. These sheets are heated in an oven until they’ve become malleable and then they’re punched with the steel mold to create the frame shape. Once they’ve been removed from the sheet, the lens portion of the frames are also removed. The grooves for the lenses are then cut using a router blade and the frames are smoothed using different machines for the nose and cheek areas.

The next step in the process is to make the temples for the glasses. The same plastic material as earlier (cellulose-acetate) is melted in an oven in thin sheets. Blank templates are punched through the sheets using a steel die. Those templates are then heated and a strip of steel core wire is inserted in the center. A machine then cuts slots into the side of the temples and the hinges are placed and secured using heat.

Tomorrow's World Today Sunglasses 2

The final step to making sunglasses involves creating the lenses. When it comes to sunglass lenses, you first start by adding the colorant. This can either be done by adding color to the molten lens material initially or with a chemical coating on a finished lens. Regardless of which is chosen, molten plastic is cast into a mold that creates the basic lens shape (either round, square, cat eye, etc). The lens is then sent to a machine called the curve generator which shaves a curve into the back. Then an edge grinder is used to further shave the outer shape of the lens into the desired shape. Finally, the lenses are coated with an anti-reflective material and are mechanically snapped into the groves of the frame.

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