DIY Syringe Pump Version 3!
Posted by aonomus on April 2, 2010
So after a completely failed iteration of the syringe pump (constant jamming of the syringe plunger, hair pulling, etc) that followed the first pump, I’ve come up with a much more compact syringe pump that fits onto a standard project case.
The main difference between this version, and the previous version is the orientation of the mechanisms. The original had the stepper motor behind the plunger, while this version has ‘folded’ in on itself, and has the stepper motor underneath the syringe. The effect is a compact syringe pump that does not take up the entire desk.
The next step is to bolt the pump assembly down onto the case, design the software for a PIC based controller for standalone operation with optional external control, and actually use this for microfluidic devices.
Procrastinatus 
Phillip Fain said
Good day!
I was wondering how you built this pump structure? We tried designing our own and so far this has the best design structure we have seen. We are a bit curious how does the mechanism work.
aonomus said
Laser cut acrylic, threaded rod for the structure (1/4″-20) and for the leadscrew (10-32), and a NEMA sized stepper motor. I would strongly recommend getting proper leadscrews and leadscrew nuts from a supplier like MacMaster Carr, however they don’t do business with Canadians, so I had to improvise. There are some bugs with this structure, one day I might revisit it, however it isn’t a priority.
Phillip Fain said
We had problems with the threaded rod, its difficult to thread apparently and the nut doesn’t quite fully “flow” smoothly. Where did you get your rod anyway? We had to fabricate since we couldn’t find one that like this.
aonomus said
There are 2 problems with threaded rod.
1. Roughness of the threads can cause friction in the leadscrew action
2. Runout, eccentricity, and bends in the threaded rod – elliptical movement causes binding of the nut
Pick the straightest stuff you can find if possible