Dean's Geodesic Dome and N-gon Pyramid Maker by M_G

Last crawled date: 3 years ago

As part of on-going collaboration with the Crawford School of Art and Design in the area of 3D printing we are producing parts to be used by, Dean O'Connor, a final year student in his work. Some pictures of the installed piece are included here.
Link to Dean's page on Crawford School of Art and Design's exhibitions website:http://crawfordexhibitions.com/exxit/?portfolio=dean-oconnor
Link to his Blog: http://deanoconnorartist.blogspot.com/
In this case we are making flat triangular shapes to be used to construct a large geodesic dome as part of a piece on the un-realised promises of utopian architecture (or so is my engineering brain's understanding of the piece). The piece will be translucent enough to allow internal projection of colours or images to show through to the outside surface. As part of illustrating the theme of unrealised utopian dwellings the piece will attempt to show the imperfections of manufacture and assembly that appear as a result of its imperfect creation. So that means we need to actually ensure some of the features and flaws possible with 3d printing (such as curling, build platform surface texture, bits of torn kapton stuck in the first layer, residual colours from other prints, honeycomb pattern, gaps, printed surface texture) are included or even accentuated in these pieces... which is an interesting an unusual request!
The photographs of all the triangles prepared were all printed on the same machine with the same white plastic. The different colours and tones come from various sources including: black marks drawn on the filament to ensure the filament is being drawn into the extruder correctly, pieces of different colour plastic being left on or falling onto the build platform and being incorporated into the print, Kapton tape unintentionally incorporated into the build, white ABS glue used to patch over small tears in the build platform, acetone and white ABS putty used to repair damaged pieces.
A simple geodesic dome can be made with triangles joined edge to edge. In this case 10 equilateral triangles and 30 isosceles triangles. The isosceles triangles form 6 pentagonal pyramids. The equilateral triangles fill in the gaps. The dome will be about 30cm (1 foot) in diameter.
To make it transparent enough to allow the projection to show through to the other side the parts will have to be very thin. The original idea was to use totally flat triangles of 2 or 3 layers thickness which could be assembled like paper craft models. However, these tended to bend when being removed from the build platform, curled up at the corners, were difficult to assemble and were not very strong once assembled!
The design was modified to include the following features:
mouse-ears at apexes to prevent curling
a thick rim around the edges to provide a large bonding area for strength when assembled and resist bending when removed from build platform
angled edges to make for easier assembly, with the angle chosen to ensure the edges meet at the correct angle for assembling pentagons
a triangular cutout giving a thin central region to enhance transparency
Expected print time on a Thing-o-matic is about 20 minutes per piece or 13 hours in total! O_O;