So it's been a while since I've put an update on here, but I have been busy. 

I made about three revisions of the paste extruder, that all use a luer lock syringe to hold the ink, and a stepper motor and M3 screw for the linear motion. 

I'm in the process of working on getting the z zeroing to work. The luer-lock tip has to be re-zeroed after each changeout, and the Z deviation the traces can stand is in the range of below 50 microns, ideally 20microns.