Dosing pump for nema17

[iLMaRiO]

Any working and tested dosing part for nema17 stepper motor ?
I've found multiple projects, printed a couple of them, but there are many drawkbacks:

- A LOT of hours to print
- the one i've printed prints in 1 hour but the water goes back every time the motor stops making it totally unrealiable
- most of them are designed for hoses different than 4 ID / 6 OD mm , like the standard areator hose.

Any working project for a pump that doesn't have that flaws ? Even better if without steel bearing (3d printed would be ok)
I need something easy to print without tons of parts

As most of them require many hours to print and maybe some hardware to buy , i would like to know which one is better (and tested) to not trash aways hours, filament and hardware

 

[Reefing Madness]

BUMP

 

[Arthur_Dent]

I've been considering buying a few of these, as opposed to printing the dosing heads, for a project I am working on. For the price, you get the stepper, the head, and you'll just need to bring the driver(s) and the logic.

30.72US $ 21% OFF|Peristaltic Pump With 42 Stepper Motor Dosing Tubing Hose Pump Small Flow 0~160ml/min - Pumps - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[Arthur_Dent]

looks like they also sell this as a "head only" option, if you prefer to bring your own steppers: https://www.aliexpress.com/item/32913632152.html

 

[iLMaRiO]

interesting but where is the fun? :-D

 

[Arthur_Dent]

interesting but where is the fun? :-D

That's fair. Why not design one in Fusion360 from scratch?

 

[iLMaRiO]

That's fair. Why not design one in Fusion360 from scratch?

Because i'm a linux user and Fusion doesn't work on Linux (and I'm absolutely unable to use FreeCAD)

I'm trying to design/customize some with Thinkercad and OpenSCAD but without too much success.

Is not clear, to me, if to customize an existing pump made for a 6mm diameter hose to a 3mm hose should I just increase 3mm of each bearings, or increase the rotor or something else

 

[Arthur_Dent]

XEN and a free trial of Windows, then?

I would approach the problem like this:

Take the diameter of the "cage wall" that the bearing presses the hose against, and subtract the fully compressed thickness of the hose (call it C, which is equal to (OD-ID)*2) that you are using. That tells you what the OD at the bearings' surface should be.

So, for 6mm OD (4mm ID) hose, with a "cage wall" diameter measuring 250mm, you get:

250 - ((6-4)*2) = 246mm, where 246 represents the OD the bearings need to run at to fully compress a 6mm OD/4mm ID hose against the "cage wall".

If we assume the 3mm hose has a 2mm ID, then:

250 - ((3-2)*2) = 248mm. So.... the bearings need to run 2mm closer. Scale the rotor on the X and Y axis up by 2mm and this should get you there, I think.

Hope this helps.