High precision 20uL pipette

thingiverse

This is fully functional pipette capable of measuring volumes between 5µL and 20µL with comparable precision to a standard P20 pipette. The design is based off of https://www.thingiverse.com/thing:255519 and uses cuts of latex gloves to form a membrane-based air displacement type micropipette. This pipette is able to measure smaller volumes with higher precision due to a lever mechanism that reduces button presses of a centimeter or so down to a few millimeters at the membrane interface. I have provided data as to how many turns of the button translates to changes in measured volume but this will need to be calibrated for each printed pipette so the accuracy may not be guaranteed. This project was actually completed back in 2014 and I'm not entirely sure why I never uploaded it. Possibly, the assembly guides were getting a bit complicated to make. Below are some assembly tips which should help but are by no means a complete guide. Assembly Tips: You will need a few cheap pens, mainly just the springs and ink cartridges. First you will need a pen ink cartridge and spring cut to fit inside the head case. This assembly should be the same as for the Biropette (assembly steps 2/5) https://cdn.thingiverse.com/assets/ed/92/35/cc/e0/Pipette_v15.pdf Use a leftover piece of pen and glue to hold the lever in place. When finished, the lever should press the pen cartridge down enough to barely press on the membrane on the pipette head. The button assembly is going to be the trickiest part so I'll try to explain it the best I can here. Body parts A and B should interlock and fit pretty solidly around the head case but do not tape it down yet. Cut one of the ink cartridges so that it will fit between the small limiter screw and barely fit through the hole in the button limiter. You can glue this segment to the small limiter screw and fit one or two pen springs over it. Feed the pen through the lever and the button limiter and adjust the limiter screw as necessary until the assembly allows you to press the button limiter and spring back. The volume you measure will be determined by how much you screw in the button since this will hit the pen you just inserted. Videos of how it works: https://youtu.be/oY5QMazP4l4 https://youtu.be/wxp85X_9v54 https://youtu.be/sPJaCBCXeoI Videos of assembly guides: https://youtu.be/_P9So7ywgTk https://youtu.be/DnkBVM0cAXI I recognize the assembly guides are far from complete but if there is enough interest in this thing I may update it to be more in-depth. Questions and critical feedback are welcome.