How Eyeglass
Frames Are Made

  1. Start with a sheet of plastic called cellulose-acetate, which is derived from cotton and is flexible and strong.
The quality of acetate greatly determines the quality of the finished product. There are literally thousands of color options and treatments. 
2. Specialty frame designers use software to create technical drawings of the glasses.

They take into account the three important size elements of glasses: the length and thickness of the nose bridge, the eye size (distance across the lens) and temple size (length of the arms). This is where details like a key-hole on the nose bridge, thickness of frames, etc. is decided.
3. A lathe or die is used to cut the frontal shape from a rectangular slab of acetate.

The center of the frame is carved from the rectangular slab.
There are grooves cut out of interior for the lenses.
Then a lathe cuts around the exterior of the frame.
4. The frontal frame gets smoothed out using tumblers often times filled with beech and birch wood which leave behind resin.

This smooths out all sharp edges and prepares them for polishing.
5. Temples are also cut from the acetate often using a stamping machine as opposed to the lathe.

6. The temple pieces are heated and a narrow strip of steel called a core wire is also heated. When the right temperatures are reached, a core wire is inserted into the center of the softened temple.

The stamped temple is heated and a core wire is inserted.
This core wire adds strength and enables adjustments later so that the glasses fit better.
9. Small slots are cut in the upper corners of the frontal frame and half of the metal hinge is put into each slot.

Some manufactures use a capitron machine that induces ultrasonic vibrations in the metal hinges and creates heat of friction. The friction causes the plastic of the frame to melt locally around the hinge to bond the hinge to the frame which is more secure than gluing or other types of bonding or mounting.
10. The temples are then connected to the frontal frame by screwing the hinge together.

11. The ends of the temple pieces are then put in a machine to curve the end to go behind your ears.

12. One more round of polishing and smoothing is usually done.

13. Final inspection usually includes making sure the glasses are level, hinges are secure and adding demo lenses or sunglasses lenses.  

Frame manufacturers typically don't add prescription lenses. That is done by lenses laboratories that are certified and specialized.

At DITTO, we take extra measures to make sure every designer brand sold on our site uses high quality acetate and strong hinges so the glasses you receive will look and feel premium and stand the test of time. We hope you see the difference!  You can find our glasses collection here