3D Printing Complex Hulled Stuctures

After printing a number of solid models, and noticing the intricate in-fill patterns that were produced, I became interested in producing entire objects out of these more complex spatial arrangements.

The idea in my mind being that this would save plastic, and potentially explore some ways of making large, light, and strong 3D objects.

To begin with I thought about constructing a geodesic dome in the style of Buckminster Fuller.

This would involve a triangular lattice in the shape of a dome.

My searchings on thingiverse did not produce much, however google was my friend and I arrived at:

George is looking good on the homepage, and a sierpinski triangle he is holding! Magnificent.

These are the sort of complex hulled objects that I am after, and pre-prepared STL files to boot. Thanks George.

My eye is taken by the Michael Goldberg polyhedra:

Michael Goldberg Polyhedra

This is a model of a polyhedron first described by the mathematician Michael Goldberg in a 1937 paper. (It is “8,3” in his series of such polyhedra.

 

And the truncated 120-cell looks simply amazing also:

Truncated 20 Cell Tetrahedra

A 4D object made of 120 truncated dodecahedra and 600 tetrahedra

 

 

The Michael Goldberg Polyhedra looked like the most acheivable, and having only a single outer hull, and no nested forms, this would be a great first test of an object with a complex outer hull.

First I turned on the batsignal, then I got to work with my fantastic little Portabee.

 

Polyhedra-Portabee-3D-Printer

Begin to fabricate Michael Goldberg’s Polyhedra

 

Polyhedra-Portabee-3D-Printer

Here we go

 

Polyhedra-Portabee-3D-Printer

The hexagonal outer hull works very well with the fused depositation, retraction is turned off, printing speed is 250 mm/s

 

Polyhedra-Portabee-3D-Printer

The shape lends itself to high speed printing, very little excess printer head movement.

 

Polyhedra-Portabee-3D-Printer-Complete

Test article produced, printing was halted before finish to commence printing of a second, larger, Goldberg Polyhedra

 

Polyhedra-Portabee-3D-Printer-Dual

Smaller and larger, both shapes have excellent strength, standing or jumping on them simply hurts the foot.

 

Polyhedra-Portabee-3D-Printer-Mounted

Mounted Goldberg Polyhedra, ohh thats naughty.

 

So, in summary, 3D printing a hull out of a complex hexagonal structure looks like a winning strategy. The overhang of each layer at this size was within the bounds of each smaller hexagon, and each closing of a smaller inside shape prepared a solid next level for printing.

Benefits exist in terms of saving plastic, and the strength of the object was very good.

 

The truncated 120-cell shape mentioned earlier is next on the list, and then on to verifying and exploring the rest of George’s fantastic STL files.

 

Until next time, thanks for watching!

 


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