We are building a big size 3d printer (a university project). It will be cartesian type, 2m×3m×1.5m. Will use Openbuilds c-beams as linear rails, Nema34 steppers for X and Y, 6 Nema23 on wormgears with sfu2005 ballscrews for lifting the bed up and down (Z). This is a pellet extruder with 4mm nozzle (have exchangeable nozzles with different sizes). Tested with ABS pellets and working flawlesly. Extruder is the first “milestone”, so we passed it 
Is it it fed by pellets?
yes 
Nice, gonna have it machined or something?
@Zviad_Sulaberidze Looks great, is it for extruding filament or printing? Also, what is the estimated cost for this build?
Please put a description on this post
I have updated the post
Is the screw progressive? What is the thermal separator made of?
no, screw is a regular auger bit, but polished (original one did not work, had too rough surface in cut part). the heat breaker is a solid PTFE
Interesting. I look forward to seeing your results. Don’t forget a good write up, even if the ultimate conclusion is that it’s just not working properly.
This would be great to mount to the MPCNC, keep us updated on this project. I for one am interested. ^^
I was able to hand grind a progressive screw from a concrete bit. From the little I understand, the commercial ones are progressive. I might be able to make one for you, if you give me measurements.
Your extruder is vertical / down feed. Industrial ones are horizontal. Maybe that’s why it works? I really don’t know. Offer stands, if you’re interested.
thank you, will have in the sight. Those - horizontal ones act also as a piston, for injection so they have good pressure isolation with the compressed space, apart of the compressed plastic
I love this! I have built many large plastic extrusion screw for industrial purposes some upto 23 feet long for high volume extrusion
@Daniel_Kruger are you referring to a conical shaped screw when you mention progressive? Such as larger diameter on the infeed and smaller diameter on outfeed tapering gradually?