7th Stellation Icosahedron Folded

Summary

The 7th stellation of a icosahedron. It's an inspirational mix of playing around with the 1st stellation and recent experimentation with thin sheet foldable designs. A design was chosen that had points made of an even number of sides so multicolor printers could be used to alternate colors.

There are three different versions, each with the same assembly instructions. They differ in their assembly feel due to the varying thicknesses of the sheets, which affect their rigidity.

Demo and assembly at https://youtu.be/3rjN17kADN0

Variations

Single Color

• 7thStellation_SingleColor.stl
  For single color printers, or if you're allergic to schmancyness.

Two Color

• 7thStellation_2Col_Frame.stl
• 7thStellation_2Col_A.stl
• 7thStellation_2Col_B.stl
  For printers that support two or more colors. Technically, you can use 3 different colors, but the filament for the frame is hidden, so you can just reuse a color from A or B.

Two Color Hex Padded

• 7thStellation_HexTex_Frame.stl
• 7thStellation_HexTex_ColA.stl
• 7thStellation_HexTex_ColB.stl
• 7thStellation_HexTex_PadA.stl
• 7thStellation_HexTex_PadB.stl

For up to 5 colors, that have a raised honeycomb pattern (like the pattern you'll see on a shower mat, so your feet don't slip). This actually has 2 extra levels of being raised, first for an inset raised surface, and then another level for the honeycomb. This means it takes a bit more filament, and the sheets will be thicker, making them more rigid.

Printing

Pick which variation you want to print, and then print 20 of them.

PLA or PETG should work fine.

The design has a tab that can be pulled to peel the thing off the print bed.

It is recommended that the bottom fill pattern is changed to Hilbert Curve, so that you're guaranteed not to have a fill pattern grain that lines up with the folding direction. If the normal Monotonic diagonal lines are coincidentally aligned with folds, they can snap when folding. Other fill patterns can also work, but Hilbert Curve is the best protection from lining up with folds from any printed angle.

When the print is finished, make sure that the printed plastic is cooler than its glass transition temperature. This is the temperature at which the material is no longer molten, but will take on permanent physical changes if deformed. If the plastic is too hot when peeled off the bed, the sheet can have a curl from peeling it permanently in its structure. You can let it cool by waiting, maybe with a fan - or if it's on a bedsheet, lift the sheet and fan it for a short while.

Assembly

See the project video for assembly demo.

1. Tear off all the release tabs.
2. Fold the fold guides (the thinner parts of the model) along the cone height seams of the models.
3. Push the cone height male tabs into their aligned slots.
4. You should now have assembled floorless pyramids that have alternating male/female tabs at the bottom.
5. Connect the male/female rings to 5 different pyramids to form a ring.
6. Ensure each male/female tab is tightly connected together. Manipulate the tabs from behind if needed.
7. Connect all the other pyramids to that main assembly in a similar way. Around the halfway point of assembly, it's not too important to tighten the tabs, as long as the tabs are correctly slotted into each other.
8. The last pyramid will be the hardest, especially because you will not be able to manipulate from the back/inside of the model. Prioritize getting all the tabs slotted; you may end up separating previously tightened tabs across the model to get the space to match the tabs together. This is fine.
9. Make sure all tabs across the entire assembly are correctly slotted and tighten the tab connections by carefully pushing pyramids inward.

Fold the tabs as needed to achieve the desired space and angles for assembly. Note that folding the female tabs may slightly reduce the height of their slots, making it harder to interlock the base of the tabs. Try straightening the tabs from behind, or expanding the hole at the base of the male slot with a small flathead screwdriver.

Safety Warnings

If you have a print with stubborn adhesion to the bed, be careful when picking up the corners with your fingernail. It's rare, but not impossible, for the sharp-and-thin feature to slip into the nail bed. For added safety, it's highly recommended to use the release tabs.

The tip of the assembled cones will be somewhat sharp. Do not throw at people or animals.

Factoid

Miscellaneous fun fact: When you fold the plastic along the creases, the plastic will whiten due to stress. This is called crazing. (The more you know 🌈⭐)