Scallop Earrings

For my design class (Materials, Tools, Techniques, and Prototypes) I created a 3D printed Scallop Shell to be worn as earrings. I was interested in printing a piece that has symmetry and simplicity. In this instructable, I'll explain the process to create the earrings from start to finish. Experimenting with 3D printing for the first time was a great experience, and I look forward to more creating in the future!

Morphology

As mollusks develop in the sea, their mantle tissue absorbs salt and chemicals. They secrete calcium carbonate, which hardens on the outside of their bodies, creating a hard shell. The shell of a scallop consists of two sides or valves, a left valve and a right one, separated by a plane of symmetry. Most species of scallops rest on their right valve, and consequently, this valve is often deeper and more rounded than the left valve, which in many species is concave. The shell may be smooth or sculptured with radial ribs, which may be smooth, scaly, or knobbed. Scallops range in color from brilliant red, purple, orange, yellow, or white.

Source

https://en.wikipedia.org/wiki/Scallop

https://www.britannica.com/animal/scallop-bivalve

https://www.int-res.com/articles/ab2010/11/b011p149.pdf

Photogrammetry Software

• Metashape

Prep Model

• Meshmixer

3D Printers

• German RepRap X350 Pro
• Stratasys J750

Jewelry

• Ear wire with ball
• Gold tarnish resistant wire
• Pliers (3 in 1)
• Gold Paint

Other

• iPhone
• Phone tripod
• White backdrop
• Three-button mouse with scroll wheel

I took some pictures of potential photogrammetry objects and narrowed them down to three that would capture some interesting textures and shapes (cactus, conch shell, and scallop shell).

I tried to avoid very large objects, very small objects, objects in motion, transparent or shiny objects, and overly complex objects.

My process included a bit of trial and error. I first experimented and took pictures on a black backdrop, and later discovered it wasn't the best setup. Next, I tried a white background which gave much more promising results. It would be easier to use a lazy Susan, but because I didn't have one handy I just simply rotated the object manually. It may be best practice to use a tripod, but I found doing taking shots freehand works also. Main tips:

• plain background (preferably white, depending on the color of the object being scanned)
• minimal shadows
• a stand to prop the object on to get a lower angle

Take one picture, then rotate the object slightly until you're back to the first shot (about 15 times all around). Then repeat for angles above and below. In total, I had about 40-45 images for each object.

Upload your images into your desired photogrammetry software (Metashape). I followed this process to get my model https://agisoft.freshdesk.com/support/solutions/articles/31000152092. It guides you through a step-by-step through Metashape.

Check your model out to make sure the object was scanned properly. Here you can see the cactus didn't turn out as well as the other objects, so this was where I narrowed down my models and chose which objects were going to be printed. I decided to print the scallop shell because of its symmetry and clear design for my final earring piece.

In Meshmixer I inspected and cleaned off my model. I closed all gaps, made a hole for my earring attachment, and turned the object into a solid.

I printed my model using the Stratasys J750 that was available in my school's lab. I initially printed with the German RepRap X350 Pro which came out with a layered texture. I then printed the same scallop again with the Stratasys J750 which uses resin. The results came out much better and used this material for my final earring design. 

My original idea was to paint the shells gold to match the gold wire, but the paint material I had didn't apply well to the printed model. But with the resin material, I decided to keep it a white color for simplicity. On a later date, I plan to attach a gold hoop around the shell as shown in the image above to close off the earrings and add a nice touch

This is a great video that shows the style and technique I was going for. https://www.youtube.com/watch?v=SwgXzROPq7k&t=241s

Hope this was helpful and happy making!