Originally shared by René Jurack
Finally got hands on the nozzle for my next printer 
Okay, two questions chuckle:
- What nozzle diameter is that?
- How do you get that thing to temperature (and keep it there)? Purely at a guess, even the famed E3D Volcano could kinda, sorta have a hard time keeping up with that…
@Ingo_Ulrich In the pic, it is 6mm.
Heating is done by generic ring heaters, several of them and with different temperature areas to preheat and premelt the pellets.
what do you want to print with this? a house?
6mm wow!!! I was expected to test a big nozzle on my printer like 1.2mm hahaha! You will make very big stuff. I have to see that.
@Rene_Jurack So, sizewise somewhere dead center between the ‘standard’ 0,4mm nozzle and the ‘print your own house in concrete’ size… Okay, the printer for those has got to make the Parts Daddy look small in comparison…
(For the ‘printing your house’ bit, I was referring to something like the following video - printing gets visible at 0:20…)
i wonder if on those dimensions some iris (non overlaping) or needle (valve) would be beneficial.
@Ulrich_Baer would definitely want a valve or a positive displacement pump or something for concrete. A quarter-turn ball valve might work well. Big plastic injection machines often use back-pressure check valves so a little pressure is required to get them to start extruding, which is a nice passive approach.
@Ryan_Carlyle i was thinking of something like my hex-box as a nozzle so you can vary the orifice and close it too https://plus.google.com/+UlrichBaer/posts/Mj5QQeVCRxp
in case of a displacement pump - have you seen my “Vorterant”?
No valve or such needed, I did clever on the nozzle-geometry 
@Rene_Jurack hope you will show - when it is time!
Is that for the stainless steel filament?
@Ulrich_Baer have not seen, link?
@Ryan_Carlyle I made multiple posts - either just search in G+ for “Vorterant” or see just 2 of the posts here https://sites.google.com/site/ulrichbaer/tdi/tech/vorterant
@Ulrich_Baer am on my phone and don’t sprechen deutsch looks like a type of progressing cavity pump using Reuleaux rotors?
@Ryan_Carlyle Yes exactly (sorry my posts are in english) - here you can see it pumping low viscosity foam here https://plus.google.com/+UlrichBaer/posts/A2aCVx6kMMi or here https://plus.google.com/+UlrichBaer/posts/5E9ev189bAv I also used it for syrup https://plus.google.com/+UlrichBaer/posts/YkNL9kA4ugH so this would probably work for concrete too - in a geared version the rotors are not in contact with each other so it have to work.
@Ulrich_Baer yeah that would be a good approach for concrete I think. If you can get adequate suction at the inlet anyway… not sure if you would also need a gravity hopper or pre-feed auger or something. (I’m very interested in a concrete hangprinter build that mixes on the fly from a powder delivery line and water delivery line, but surely wouldn’t have the time to build one.)
One thing I have been considering for a long time is adding a positive displacement pump to a screw auger for a pellet extruder. Most of the problems with pellet extruders come from the fact that they are variable-displacement pumps that don’t respond super fast to transients, so a screw-plasticizer stage followed by a metering pump could be very advantageous. Helical progressing-cavity pumps are ideal for this because they can be run on an axial shaft from the pellet feed side without requiring high-pressure melt pool seals like a gear pump or piston pump.
very big nozzle
Hmm… gives me an idea for something I would love to see done… but would be reeeeeeeeallly complicated.
A giant 3d printer that can handle large props for shows, like, say, a stargate. Have an assortment of various resolution extruder heads (for FDM) or lasers (for SLA), so you can build the large portions quickly and then fill in the fine detail over a large area simultaneously when you get to the surface detail. That way you get the benefit of faster print times for the non-hero sections, and still get the detail on the facing side.