DNA Model (Expandable)

thingiverse

This DNA model is composed of 5 printable parts that fit together like puzzle pieces, allowing for theoretically infinite sequences of DNA. The pieces shown are the sugar-phosphate backbone, nucleotides A, T, G, C, all coming together to form the double helix DNA. This was modeled after B DNA and has accurate proportions in regards to diameter (20) and rotation/bp (34.3 degrees). The C and G nucleotides connect with 3 prongs to illustrate how many bonds they use, same with A and T having 2 prongs. After printing the individual components, I used small files to shave down parts that fit together (my printer isn't very precise). I then painted the components to distinguish the different features, ending with piecing them together. I only did about 1.5 turns for this model and it turned out very nicely. It can stand on its own with >1 turn. I did a 15% infill to ensure a faster print and added a raft to the backbone due to the lack of surface area touching the plate. I wouldn't recommend a raft on the nucleotides, it ends up with a nasty finish and takes forever to get off.