Printing molecules (flexible resin)

What you see is a conformer of Tetraphenylporphyrin (porphyrin derivatives are a common handyman in the nature. It does things like solar energy convertion (chlorophyll, dye-sensitized solar cells) , carry stuff around (hemoglobin), or even act as a motor in some bacteria so that they can swim around)

I used flexible resin (it is quite a flexible molecule, and I intended the print as a key chain). First I got the coarse mesh from Visual Molecular Dynamcis. It looked like a Voronoi tesselation art, but I didn’t want to go for this look. Thus, I refined the mesh and filled it with autodesk meshmixer. At some point one software decided to use U.S.A. units instead of SI, thanks to Formlabs software being prepared for it, it was corrected very easily.

I found using flexible resin much harder than the clear one. (it is the first time I am using this material, and I am a first timer in any manufacturing process anyway) . Towards the end of the print, the build platform was pressing the model down as it was unable to really understand the depth correctly, so that the model was being flexed. This ends up as unaligned print layers. I solved this by reducing the inclination and adding thicker supports at molecular points. The suggested support side is really not suitable, as it destroys the hydrogens, and leaves ugly marks which can not be sanded. I used a mixture of .95 1.2 and 1.8 supports depending on where they are placed. The picture you see is the 6th iteration which came out to be usable. It can still be improved a lot though.

The model was feeling sticky even after IPA treatment and half a day under the sun. The suggestion of putting it in water under the sun worked really well.

I tried to sand the support joints leftovers with limited success. The sticky white residue can be removed by water. I was unable to solve the shiny damage left when I was taking away some of the larger support points, as it would destroy too much detail.

Finally I added a gloss acrylic finish

The mandatory physicist cat is there for the scale… of the quantum state… (the cat scale shown is a quantum entangled state of sleeping and looking for attention)

another picture:


I’m surprised the gloss comes out that nicely! Looks awesome!