Need Replacement Eyeglass Frames? Download Them.

3D printing technology is creating new opportunities for households to save money by replacing things that would otherwise be somewhat expensive to buy again. Take eyeglass frames for instance. These can cost hundreds to replace. I can imagine a future where people no longer select frames from their optometrist, but frame designs can be downloaded and printed at home. Of course, you’ll still need glass lenses made for you. But if the lenses were a standard size, they could fit a number of frame models, or allow people to make their own.

Recently my wife had been struggling with some eyeglasses of hers. The darn lenses kept jumping out of the frames. The lenses need to stay in the frames! One time when a lens came out, I took the opportunity to scan the dimensions of the lens and go to Makerbot’s Thingiverse to see if I could find some nice replacement frames. I found a style of frames that my wife typically likes. These “D&G” frames. Normally she would choose black frames, but I only have red and white ABS plastic right now.

Make The Model Work.

One of the things you’ll notice when searching thingiverse for eye glasses is that none of them accommodate lenses. They’re all just superfluous face decoration. If you want to fit existing lenses into any of them, it’s going to take a little bit of work to make that happen, and it won’t necessarily  help the next person, whose lenses are a different shape. You can see why thingiverse doesn’t have any models like that.

To make the model work for the lenses from my wife’s glasses, I opened the SKP file I downloaded in SketchUp (free software). That’s where I’d need to make the changes to the model.

To know what changes to make, I needed to measure the lens as best I could. I attempted to scan the lens using an Xbox Kinect controller using Skanect (free software), but the object was too small and glass to even register. Skanect and a kinect are great for scanning larger things like animals and furniture, not so great for little things. I decided I could get some pretty accurate dimensions (at least 2D) by placing the lens on a flat-bed photo scanner and scanning it. After scanning the lens, I pulled the image into SketchUp for tracing.

A photo of the lens is imported into SketchUp and two lines are drawn. One on the outside perimeter, and one within the lens. The inside line is offset enough to miss all the edge cuts.

A photo of the lens is imported into SketchUp and two lines are drawn. One on the outside perimeter, and one within the lens. The inside line is offset enough to miss all the edge cuts.

I used the lines I made to replace the lines of the original lens hole in the model. The inside line was cleared all the way through, while the outside line was only extruded part way, leaving a ledge to hold the lens.

All adjustments are made to just a half pair of glasses. When the adjustments are complete the half is mirrored and made whole again.

All adjustments are made to just a half pair of glasses. When the adjustments are complete the half is mirrored and made whole again.

Tabs are needed for the lense to snap into, so those were added next. At this point I felt brave enough to try to print both sides of the glasses. But I should have just printed one side, because more adjustments would be needed.

Using the STL extension, you can add to SketchUp 2014, I saved this model as an STL in order to open it in the Replicator G software, which will prepare it for 3D printing.

Using the STL extension, you can add to SketchUp 2014, I saved this model as an STL in order to open it in Replicator G (free and open-source software), which prepared it for 3D printing.

It turned out the lenses didn’t quite fit. That’s the problem with measuring a 3d object (the lens) with a 2D scanner. I didn’t let my lack of precise measuring tools slow me down much. In the spirit of rapid prototyping, I made some adjustments and printed another test. this time I only printed half of the front frames, so as not to waste printing time on the mirror image.

Still not quite right. One more test after this one was needed to get the lenses fitting nicely.

Still not quite right. One more test after this one was needed to get the lenses fitting nicely.

The third test print passed and it became time to print the full frames again.

Make it Yours.

The original model from thingiverse was pretty good, but many of the glasses on thingiverse are completely flat on the front, this allows them to lay flat on the 3D printer’s bed, simplifying printing by allowing them to be made without supporting any overhangs. Real glasses, however, are usually rounded around the bridge of the nose. People don’t really wear glasses that are completely flat on the front. So I added a little bit of contour to the front of the frames. Of course, that meant that printing them would require a full scaffold underneath the frames, because the lowest point of the model became the edge of the nose bridge, and the rest of the frames are higher above the print bed. I also added some reinforcement around the hinge. In the first test, the stems didn’t have much space to fit into the hinge slots and the stems caused the hinges to crack, so an adjustment was made there too.

After the prototype was considered successful, I uploaded my edited model to thingivese to share with the world. It’s my hope that more people will use 3D printing to aid in their lives, save money, reduce the carbon footprint of consumer goods, and other good things. Keychains and trinkets are one thing, but solving real problems is what I am into 3D printing for. It’s exciting to see the start of something amazing, and peer into how it might soon change our lives forever.

Whitney in her new 3D printed frames. After sanding.

Whitney in her new 3D printed frames. After sanding.

Onward and Upward

Most designs can be improved. Here are some considerations for future versions

  • Black, it’s gotta come in black.
  • Acetone vapor bath. This is a technique for smoothing ABS. The scaffolding material gets sanded off the front of the frames, but if you want it really smooth, this vapor bath might be just the thing.
  • Check the angle of the original frames. We found that these frames held the lenses so things were clear in the center, but blurry around the peripheral. If the model were adjusted to fold the front of the frames into a matching angle with the original frames, it might provide better clarity throughout her field of vision.