The short answer: Sunglasses are built in two streams that meet at assembly: the frame and the lenses. Acetate frames are cut from colored cellulose sheets, then milled, tumbled, and hand-polished. Metal frames are formed from wire and soldered. Lenses are cut, tinted or coated, and edged to fit. Hinges, screws, and nose pads join it all into a finished pair.
Making an acetate frame
Acetate frames start as solid sheets of cellulose acetate, a cotton-based plastic with color running all the way through. Machines cut the front and temples from the sheet, which is why acetate shows layered, translucent color. The pieces are milled to shape, then tumbled for days in wooden drums with polishing pellets to smooth every edge, and finished by hand. See acetate vs plastic frames for why this differs from cheap molded plastic.
Making a metal frame
Metal frames are formed from wire and sheet, usually monel, stainless steel, or titanium. The rims, bridge, and temples are shaped, then soldered or welded together, and the joints are cleaned and plated for color and corrosion resistance. Nose pads on adjustable arms are added so the frame can be fine-tuned. We compare the metals in metal vs titanium.
Making the lenses
Sunglass lenses are cut from materials like polycarbonate, Trivex, or nylon, chosen for impact resistance and clarity. They are tinted to the chosen color and category, given UV protection, and coated, anti-reflective on the back, sometimes a mirror on the front, or polarized with a filter layer laminated inside. Finally each lens is edged to the exact shape of the frame opening.
Assembly and quality checks
At assembly, the lenses are seated into the frame, the hinges and screws are fitted, and the pair is aligned so it sits straight and level. Good makers check the tint, the UV block, the optical clarity, and the frame alignment before a pair ships. The care at this stage is what separates a frame that holds its fit from one that loosens fast; it is the same alignment we check in how glasses should fit.
From our test bench. When we evaluate a frame, the making shows. Acetate that was properly tumbled and polished has a deep, even shine and smooth edges; rushed frames feel chalky and sharp at the rims. Soldered metal joints that are cleaned well stay tight; sloppy ones loosen. You can read the quality of the manufacturing in the hand before you ever check the lens.
FAQ
How are acetate sunglasses made?
They are cut from solid sheets of colored cellulose acetate, then milled to shape, tumbled for days to smooth the edges, and hand-polished. The color runs through the material, which gives acetate its layered, translucent look.
What are sunglass lenses made of?
Commonly polycarbonate, Trivex, or nylon for impact resistance and clarity. They are tinted, given UV protection, coated or polarized, then edged to fit the frame.
How are polarized lenses made?
A thin polarizing filter is laminated inside the lens material. That filter blocks horizontal glare, and the lens is then tinted, UV-treated, and edged like any other.
Part of Choosing Glasses Frames · Related: acetate vs plastic frames · Shop acetate glasses · Last updated: August 5, 2026
