I've looked at a few choices for the extruder, the one I built first isn't going to work. Looks like I'm going to need the syringe to be held in place better, this design seems to be better for less precise designs, maybe for larger volumes that don't have to be as precise. 

Ystruder - looks promising, but a little more than I need, includes a force sensor and control electronics. Might do this later on if I need feedback on the pressure

https://www.sciencedirect.com/science/article/pii/S2468067219300471

Open source syringe pump - I've printed a few parts to this one already but they aren't quite exact enough so I"ll need to adjust the designs and reprint. I like that it supports different syringe volumes. 

https://www.appropedia.org/Open-source_syringe_pump

Also bought a pneumatic solenoid valve that I'm going to test, it's the most similar to systems I've used before. Should be able to handle the highest viscosity fluids in my experience. Might be a little harder to integrate into an existing print workflow, and also requires a pump so it's not as cheap. 

https://www.amazon.com/gp/product/B07SJFV7S3/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Any suggestions from the community? Previous similar projects that used precision syringe extrusion?