Instructables
Picture of 3D Printable Adjustable Volume Pipette
Pipettes are prolific in laboratories everywhere and used to transfer variable amounts of liquid. Professional tools are calibrated and have dials that allow the user to set the volume. The following instructions are the result of an experiment to develop 3D printable and low cost alternatives to standard lab tools, such as the pipette. This simpler version uses a straw and allows the user to adjust volume using two limit thumb nuts. It should be very useful around any wet lab and works nicely with a relatively high range of possible volume settings. You can calibrate the volume but it is generally only good for low precision work. With the exception of a balloon or rubber glove, spring, straw, and some tape, all the parts are 3D printable without support using a variety of low cost printers. This is a very nice example of alternative lab tools and I hope will contribute to further work in the area. You can also find this model and some user remixes on thingiverse: http://www.thingiverse.com/thing:64977

 
 
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Step 1: Get everything together and 3D print the pipette components

Picture of Get everything together and 3D print the pipette components
Print the upper body, lower body, plunger, and two thumb gears using a 3D printer, the STL files are attached. I printed all the pieces on a Makerbot Replicator 2 at 0.1mm with 15% fill and 100% fill for the plunger.

You will need a spring, which I got from a kids Pez dispenser for its form factor. The balloon membrane or rubber glove is elastic so you may get away without the spring but it is nicer to have it. You also need some tape to seal the gap, and a straw. It is designed for standard straw diameter (which also works with the standard pipette tip) but I can upload others if there is demand, let me know.

Step 2: Make the membrane

Picture of Make the membrane
The pipette uses a membrane which is displaced by the plunger and changes the volume in the cavity below allowing for the droplet to be drawn and ejected. Depending on your printer you may need to put some sealant in the cavity and possibly around the membrane, some people have used glue which seems to work fine.
saintdeces26 days ago

is it possible to make the diameter of the straw bigger? I am trying to settle drops with a diameter of at least 1.5 in.

Breygon1 year ago
totally awesome! I work in a lab and use these all three time but the professional ones cost a bomb.... now I just need a 3D printer and I can have my own set!
kwalus (author)  Breygon1 year ago
Thanks, I hope it will help. We definitely use it in our lab for low precision work all the time. If you like it, consider also voting for it.
BrittLiv1 year ago
Wow, this is awesome! Good job!
kwalus (author)  BrittLiv1 year ago
Thanks for the comment, may consider voting for it
What a fantastic project. Very clever. :D
kwalus (author)  jessyratfink1 year ago
Thank you!
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