High precision 20uL pipette

thingiverse

This fully functional pipette measures volumes between 5µL and 20µL with precision comparable to a standard P20 pipette. The design draws inspiration from https://www.thingiverse.com/thing:255519, utilizing latex glove cuts to create a membrane-based air displacement type micropipette. A lever mechanism reduces button presses by a centimeter or so down to a few millimeters at the membrane interface, enabling smaller volume measurements with higher precision. Data is provided showing how many turns of the button translate to changes in measured volume; however, calibration for each printed pipette may be necessary, and accuracy is not guaranteed. This project was completed in 2014 but was never uploaded until now, possibly due to complicated assembly guides. Assembly tips are below: To begin, a pen ink cartridge and spring need to be cut to fit inside the head case, following the same steps as for the Biropette (assembly steps 2/5) https://cdn.thingiverse.com/assets/ed/92/35/cc/e0/Pipette_v15.pdf. A leftover piece of pen and glue can be used to hold the lever in place, with the lever pressing the pen cartridge down enough to barely press on the membrane on the pipette head when finished. The button assembly is the trickiest part. Body parts A and B should interlock and fit solidly around the head case but not tape it down yet. One of the ink cartridges needs to be cut so that it will fit between the small limiter screw and barely fit through the hole in the button limiter, then glued to the small limiter screw and covered with one or two pen springs. The pen can be fed through the lever and the button limiter, and the limiter screw adjusted as necessary until the assembly allows the button limiter and spring to press back. The volume measured will depend on how much the button is screwed in, as this will hit the inserted pen. Videos of how it works are available: https://youtu.be/oY5QMazP4l4 https://youtu.be/wxp85X_9v54 https://youtu.be/sPJaCBCXeoI Videos of assembly guides can be found here: https://youtu.be/_P9So7ywgTk https://youtu.be/DnkBVM0cAXI The assembly guides are far from complete, but if there is enough interest in this thing, they may be updated to be more in-depth. Questions and critical feedback are welcome.