A DIY dome garden house!
Dome shaped houses are nothing new, there's plenty of stuff about them out there. The idea with this project is that with the help of a 3D printer and cheap aluminium tubes you should be able to get something sturdy and easy-to-assemble without spending a fortune. For my prototype (3m high, 25 m2 floor area, frame only - no covering) I have to this point spent less than €300 for the aluminium tubes and and the filament for printing the connectors.
This particular design is for "2V 1/2 geodesic dome". For struts I'm using 20x1.5mm aluminium tubes, meaning that the inner diameter is 17mm. I have designed connectors with the proper fixed angles so if the tubes are of correct relative length, everything will fit snugly and the dome shape will come automagically. :) Use this dome calculator to find the correct length of the tubes. The connectors themselves add a total of 40mm to the "strut" lengths so remember that when using the calculator.
I've designed the strut connecting parts in OpenSCAD. This is basically my first endeavour into the 3D world so I'm sure the models are quite naïve in their construction. For some reason they take a looong time to render (like 10 minutes on my quad core rMPB). If you can optimise/simplify them, please let me know with a pull request.
TODO: moar info, fancy images and what not
Coming soon: a flexible parts section for any geodesic dome
You need 30 tubes of length "A" (see the calculator to find the correct length of the tubes. The connectors thems) and 35 tubes of length "B". The "A" variety is the shorter of them.
The connectors comes in four shapes, two for connecting four struts, one for five struts and one for six struts. The legs for "A" struts are marked with a little dot. The connectors are hollow to save some material and making it possible to pull wires through them. Or even thin water hoses…
The connectors all use the leg.scad part as a base, so if you want to edit for other dimensions of tubes you just edit leg.scad and re-render the connectors.
I'm printing these parts on a Velleman Vertex printer (also called K8400). For the prototype I settled with PLA and print with 100% infill. The parts are very strong and I haven't been able to break any of them yet. But for better durability you should use a material like Nylon which is awfully strong, somewhat flexible and doesn't wear down from UV radiation or moist. Here's what some of the parts look like:
Notes after first test assembly
The struts are bit too short for the size of dome I want (longest tubes are 1800mm). Also, they come off a bit too easy. Next version should extend 50% more into the tubes and have a hole for a screw to lock in place. Otherwise they seem to work fine and all angles are just right. And they are very discreet when in place, the entire structure looks very neat!
For next version I will also look at Nylon or PET. It's trickier to print but gives the strength and natural flexibility that PLA lacks.
This part is used at the base of the dome and comes in two versions, "L" and "R", depending on which of the legs connects an "A" strut. You'll need 5 of each version.
This part connects to 5 "A" struts. You'll need six of them.
This part connects to 2 "A" and 4 "B" struts. You'll need 10 of them.
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