Individual Project
Master Thesis: 3D Printed One-Part Glasses Frame
For my thesis project at the University of Twente, I designed an eyeglasses frame that can be 3D printed as only one part using a simple FDM machine.
I developed a unique hinge that ensures a strong part that does not require any assembly for simple and economic manufacturing. This hinge uses a compliant mechanism that bends when opened or closed. The design of the hinge gives the final eyeglasses frame bi-stable properties. This allows the temples, or legs, of the glasses to stay opened and closed.
Why eyeglasses?
Access to eyeglasses in the global South is problematic and identified as an urgent need. 3D printing allows for low price manufacturing and especially local manufacturing that does not require production facilities or high levels of education. A cheap FDM machine can print eyeglass frames in the global south for a fraction of the cost of eyeglass frames sold in the West.
Bi-stable Compliant hinge
Bi-stable means that the hinge remains in a stable state when either unfolded or folded in. Naturally, the hinge wants to stay in one of the two stable positions. Anywhere in between the open and closed position, the tension in the hinge causes the hinge to snap back into one of the two stable positions. A 90 degrees closing angle was chosen as this is convenient for designing eyegasses.
One part
The hinge design is implemented in the final frame design, making it possible to print the whole frame as one part. This allows the temples to be folded in and out, making the design just as practical as any other eyeglasses design. The resistance of the hinges apply the required pressure on the head of the wearer to keep the frame in place, even during activity.
Material
Nylon PA-12 was selected as it is strong, semiflexible and resistant to impact, chemicals and heat. The stress produced within the hinge when bending it stays below a critical limit for Nylon PA-12. Therefore, there is no strain or wear causing damage. This makes the hinge very durable. Nylon is self-lubricating, which means that wear between the two sliding beams is minimised. This also means that the hinge does not need any maintenance.
Why Additive Manufacturing?
The design was made with FDM 3D printing in mind for manufacturing. This production method allows for complex shapes and is not limited to producing one product type. Every print can be different without extra costs which is perfect for personalised products. A product can be produced to fit a user perfectly based on their size. FDM is cost effective and not dependent on production facilities.
Future
In the near future, the idea is to use 3D scanning to measure people’s head and face dimensions and digitally generate a personalized eye glasses frame that fits the wearer’s head and face perfectly. Directly from the printer without having to visit a specialist to modify the frame in-shop.
See the eyeglasses frame in action
