Moineau stepper extruder Luer lock updates

by unfold Jan 30, 2012
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Hi Unfold, could you share the delta adaptor? Thanks

Hi unfold
I think it's amazing design.In the video, I saw you use pump to push the clay, Do you use solenoid valve to control the air pressure? Besides these, how can I use the opensource like reprap to do it? Do you use marlin and arduino? Could you please give me some information about it.
My email : [email protected] Thank you!
Best wish.

No, air pressure is constant. You don't want to control the air, is pushes with constant pressure just to feed the clay into the extruder. Control is done by the moineau pump. It's drop in compatible with Reprap, you just need to experiment with steps/mm settings etc. Yes, Marlin is fine. You control it like any other stepper based extruder.

Thanks for your reply!

The air pressure is constant and feed the clay into the extruder. The extruder motor, like extruder 0 on ramps 1.4, decide the clay go forward and stop. If the extruder motor rotates, the clay will go forward from the nozzle. Is that right?

But what I want to do is that we can control motor and air pressure meanwhile. When the extruder motor is corotation, the solenoid valve is open. And other things is inverse.

yes, that's right. When motor turns, clay moves forward (or backward if it can overcome the air pressure). The air pressure is only there to help the clay move into the extruder. I don't see any reason why you would want to remove the pressure while not extruding? Air pressure works kind of on demand. Think of it like this: if the motor doesn't turn and clay isn't moving, no new air is pushed into your clay cartridge, just maintaining the pressure. If the motor turns, the pressure in the cartridge will drop and your air system will maintain the set pressure by pushing in extra air from the main vessel. If you depressurise your container in between you tend create problems if you have tiny air bubbles in your clay, also many syringes will rapidly disintegrate of you pressurise/depressurise them too often, you create little cracks that burst.

OK, thanks a lot.

What the material you used in the video? Is it a mixture of clay and water ?

Yes, it's clay with a bit of extra water but not much.

Hi, unfold

Could you tell me the specification of the luer lock you used in the nozzle and what the conector is between the inlet and the syringe?
Thank you

Posted this answer already below: These connectors come from a german company: https://www.dosieren.de/en/products/cat/luer-lock-adapter.html but look on eBay for "Luer Lock adapter" and you'll find cheaper.

How Much Step/mm are needed??

Thanks on advance

The design id 5y old, don't remember Step/mm. you'll need to try.

Another question, how can I search that conectors you use to put the serynge into the inlet??
And also, you got a metalic auger there??? Where I can find that??

first question, I already posted below: These connectors come from a german company: https://www.dosieren.de/en/products/cat/luer-lock-adapter.html but look on eBay for "Luer Lock adapter" and you'll find cheaper. The 90 degrees one you can also find.

The metal auger I ordered form Shapeways using the original STL. It's printed in stainless steel.

1] Steps/mm. No idea, I used this on an old BFB Rapman with non adjustable firmware. You'll have to experiment a bit but it extrudes at a very low RPM like 1-5 RPM range.
2] These connectors come from a german company: https://www.dosieren.de/en/products/cat/luer-lock-adapter.html but look on eBay for "Luer Lock adapter" and you'll find cheaper.
3] I ordered this from Shapeways in stainless steel. It was around 25€ if I remember correctly.


I'm just wondering how 's your integration of ViscoTec Preeflow pump into RepRap? I am doing some experiments related to 3D printing gel which is similar to paste 3D printing now,and i think Moineau maybe a good solution.So ,i'm sincerely eager to ask help with you trouble .

If it's convenient for you ,can you contact [email protected] with me?

Looking forward to your early reply!

Hi Veilivy,

will send you an email. In short, we have it running with a Marlin based setup using Viscotec's 3d printer integration kit.

I'll try doing it on CATIA.
What's the mathématical function of the rotor?

you should be able to extract from the OpenScad scripts:

Moineau Pump
by emmett

why do I only see 3 pieces to download out of the 7 yellow on the picture?

Those are unmodified from the original Thing: http://www.thingiverse.com/thing:15538

Moineau stepper extruder
by ttsalo

So does this design need an air compressor? I see some tubing in the video...

Unless the material is low viscosity enough to gravity feed you will need a compressor to push the material in the pump. So for any paste like material you will need a pressurized feed line. I have done a lot more tests with this design in the last months together with an engineering student doing his master thesis on the subject and will document the findings online in the next weeks/months.

Hi Unfold,

I'm in the process of building this. Can you upload the file for the 3D printed object to the right of the stepper in the exploded picture? It looks to be a spacer.

Hi Andzerb,

I have uploaded the file but you will probably need to change the height according to your stepper shaft. I have done more work on this extruder last month but still need to upload and document this.


You might be interested in this alternative moineau pump structure I've just uploaded.


Also I'd like to ask how you've got your cool shapeways steel rotor so smoothly polished. I know from experiance that wet sanding paper wears out almost instantly on this stuff.

Progressing Cavity Pump (cycloidical)

Thanks, rather technical explanations, sounds like you know your stuff ;)

About the steel auger, good news, it came like that!

Its probably, since the model hadn't much (and important looking) sharp corners. When that's the the case the shapeways operators tend to polish more thouroughly. I fear their grain polish will not work so well on a rather small "concave" stator counterpart, but maybe I'll try it anyway.

makes sense, I remember they have different levels of polishing that they apply. For the stator I am thinking about using flexible PLA, in commercial moineaus the stators are some rubber and it acts as a wiper.

I tried soft PLA once to make molds for polyurethane parts.

I guess its a bit prone to wear since it's really soft and its surface isn't very smooth and shiny.

An idea would be to print the complement of the stator in ABS smooth the layers out with acetone apply sepperation wax and mould the stator out of silicone (some a bit harder one). This would be well suited for high temperature applications and maybe to some extent for abrasive pastes.

I did just that but with PLA http://www.thingiverse.com/thing:204649http://www.thingiverse.com/thi... and I am now in the process of repeating the experience with acetone vapor treatment on stator cavity and rotor parts.

An idea on Moineau pumps
by misan

Might be better yes.

Wow, the test in your video looks very promising! How did you seal the motor axle? I guess it's that square black thing with the hole on the photo, but what is it?

And is that a metal rotor you are using?

Hi Drayde,

I used a shaft seal from RS Components. You can't see it in the pictures but its embedded in the thick block that sits on top of the stepper. Some water drips leak through because it is not rested to withstand the pressure I use. But its really a tiny amount. This could be solved with a second seal if needed.

Yes, I have not yet tested it but that is a steel rotor I ordered from Shapeways! Looks fantastic, the other is Alumide but is very rough. I also plan to test a rubbery PLA i got from Ultimaker for the stator. But first I have to print some parts again that I hacked but are now introducing some pulsation. After finishing some ceramic prints for a gallery opening (still using good old direct air pressure) I will continue working (and documenting) on this extruder.

so to clarify, and as you can observe, the rotor in the movie is vanilla ABS. The speed is so low that I am not expecting much wear actually.