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Mini dome with pins - Icosahedron

by t00tie, published

Mini dome with pins - Icosahedron by t00tie Aug 14, 2012

Description

This is an icosahedron dome designed to be made with drinking straws or other hollow tubes (pipe, straw, bamboo etc.).

This is a minor derivative of thingiverse.com/thing:26860
A quick and dirty hack to use pins for hollow connectors like straws/pipes/bamboo
See the thingiverse page for instructions and
desertdomes.com/pictures/dome/2vdiagram.gif
for assembly.

Look out! If you print too many connectors you may find yourself under attack from alien pentacles and hexapods (see pics of the invasion i had to fight off). Hint: the one with the extended proboscis is the leader!

Recent Comments

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Netfab fixed the files, I have to print them with a raft and support material, without it, the beginnings of the pins let go of the printbed.

Anxious to see how it looks when I have printed 30 of them.
Guess I would be needing 6 pentagonal and 20 hexagonal for half a dome :)
Interesting, because I use slic3r too (0.9.9), right from repetier, and then they tell me there is something wrong and it doesn't render the right way. Anyway, I send them to netfab and they fixed it, but i can't see if it works yet because I am printing my own designed cup now.

Will let you know if it works when I load it in slic3r without using repetier, and will let you know if the fixed files do work :)
They slice just fine in slic3r 0.9.9 now. They sliced just fine in the version I used when I first made them too. I use 3 perimeters and 40% honeycomb by default.

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License

GNU - GPL
Mini dome with pins - Icosahedron by t00tie is licensed under the GNU - GPL license.

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Instructions

I made some small changes to the mini dome so that I could build it with drinking straws.

Before printing: measure your straws inner diameter and change the scad files:
sd (last line) is stick diameter, set this to slightly less than the inner diameter of your straws/pipes/bamboo. 4.3 works for my 5mm straws with my reprap. Compile (F6) and export stl.

Print one and test that the straws fit snugly, adjust as needed. When they fit adjust both scad files. You need
* 20 x Hexa-connectors
* 6 x Penta-connectors

I used slic3r to print these on three plates. There is some bridging so it helps if your printer isn't awful at bridging but it needn't be perfect.

* 35 x long straws
* 30 x short straws

I had bendy straws so I cut the long ones just below the bend. My printed connectors are approx 2.5cm point to point and my long straws 16.5cm. So I entered 2.5+16.5=19 into
desertdomes.com/rev2calc.html
as my A length. The page says B is then 16.8 so I cut my short straws at 16.8-2.5=14.3cm.

It turns out I'm human so after all those calculations I just eyeballed my short straws as approximately 2cm shorter than the long ones! :-)


For assembly follow this diagram
desertdomes.com/pictures/dome/2vdiagram.gif
or use my main picture. Green and blue are the long connectors A, red and pink the short ones B. When assembling the X on top of the six-pin connectors indicates the four pins that use the long A connectors.

The pins are slightly tapered to ease printing and straw insertion.

Note on license: I chose the same license as the immediate predecessor to this derivative, IANAL, let me know if I should've chosen something else.
I'm trying to slice these parts, but they only show a cross when I slice them in slic3r, tried multiple settings, but it just only shows crosses to print. Do you know if there is an error in the files?
They slice just fine in slic3r 0.9.9 now. They sliced just fine in the version I used when I first made them too. I use 3 perimeters and 40% honeycomb by default.
Interesting, because I use slic3r too (0.9.9), right from repetier, and then they tell me there is something wrong and it doesn't render the right way. Anyway, I send them to netfab and they fixed it, but i can't see if it works yet because I am printing my own designed cup now.

Will let you know if it works when I load it in slic3r without using repetier, and will let you know if the fixed files do work :)
Netfab fixed the files, I have to print them with a raft and support material, without it, the beginnings of the pins let go of the printbed.

Anxious to see how it looks when I have printed 30 of them.
Guess I would be needing 6 pentagonal and 20 hexagonal for half a dome :)
I think these can even be made with a smaller 'body' to make reproduction faster and make them even use less material.

I don't know if you're ever heard of the 'Operation Manual for Spaceship Earth' by Buckminster Fuller, but in his view on finite resources on this planet, and his implementation of the geodesic dome into architecture, I'm sure he would love to see this modular piece re-designed to use the least material possible ;)

Great design nonetheless, I will print a few tonight, actually, this part is what inspired me to build my own 3D printer, so thanks for the inspiration t00tie!
That's nice to hear! The easiest way to use less material is to use less infill . If you really want smaller adjust in the scads. These don't use a lot of material anyway unless you are upsizing for pipe or similar!
If you really can't use openscad and need another size ask nicely and I'll probably help you. If you make one please share pics but remember, I'm not the one who deserves credit here, C60, EFFALO and obijuan did all the hard work.
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