So I designed and built replacement temples that I like better than the originals.
I just built the temples, but the entire frame could have been made with the same techniques.
I made it at Techshop: http://www.techshop.ws
Step 1: Materials and Equipment
Printing plastic filament- I used ABS for prototyping purposes, but nylon is recommended as it is less likely to shatter on impact.
3D CAD design software - I used Autodesk Inventor
Step 2: Analysis
-Color matched the rest of the frame.
-Flexible plastic- pretty sure it is nylon.
-The metal insert created a breakage problem.
-The metal insert design did not appeal to me - a bit too Euro-Elvis (sorry Jean-Paul).
-The temple ends curved in too abruptly- created stress on the hinge and denting my skull
So I needed temples that were a bit longer and would have a more gradual curve. The fit needed to be secure enough to use for recreational activities. Color matching would be difficult- so maybe a complementary color instead.
Step 3: Design
2. Determine the proper length and curve for the new temples.
3. Draw! I created a horizontal profile view, extruded the horizontal, and then projected a vertical view that was cut-extruded from the horizontal. The edges were rounded using a variable filet feature.
If I did it again, I would probably draw a wireframe and loft the shape.
Step 4: Print & Assemble
I used ABS filament at fine resolution with 4 shell layers and 90% infill.
The holes for the temple screws were fairly small, and therefore needed some touch-up with a roto-tool.
The temples screwed right into the frame and fit quite well!
Step 5: Observations
This effort has inspired me to consider designing my own frames for prescription sunglasses. I have not been able to find what the requirements are for the frame shape to be able to support standard lens blanks. I suspect this could get tricky for 6-8 base curve lenses. I would definitely not use ABS, and instead would web-order nylon/resin prints for a a full frame. Nylon would probably be a bit more forgiving on impacts, and better for inserting/gripping the lenses.
The photo is an alternate design- looked nice, but the temples were a bit too long for my taste.