I wanted to write a post on simple tricks to improve the OD reading. This mainly involves holding the vial into place with a 3D printed part. I will first walk you guys through what we’ve done in the past.
First Trial - NBT Paper
The OD reading gets disrupted if there is any shaking/perturbation of the glass vial. For our Nature Biotechnology publication, we used small felt pads that we stuck into the inner wall of the aluminum tube to hold the vials in place. These would work well at first but then they would start getting worn out, making the tube very difficult to take out after several cycles of use.
Second Solution - Custom eVOLVER Caps
We started making custom nylon eVOLVER caps that had was made to fit better with the aluminum tube. This was aimed to avoid using the felt pads. The issue with these caps is that there was still wobbling in the bottom of the aluminum tube. This would cause a disruption in OD readings.
Best Solution - 3D printed Aligner
The updated recommended solution is a new 3D printed part that goes in between the glass vial and the aluminum tube to keep it from moving. This part can easily be printed via FDM printing (typically ABS or PLA). The solution involves a part you can clip onto the tube (after autoclaving). FDM plastics are not autoclavable, so please do not try.
Here is the part (black piece):
Insert into the aluminum sleeve and rotate the tube to tighten the hold inside the Smart Sleeve.
Want to 3D print your own?
STL and Solidworks files for tube aligner can be found on Github
Place the part in this orientation, without supports. The part prints best with a raft at the bottom.