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Hey! This thing is still a Work in Progress. Files, instructions, and other stuff might change!

MGN12 Prusa i3 Clone

by Tonlaar Feb 9, 2018
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Will this work with the origina prusa i3 Mk2? thanks!

I migrated from a modified Prusa i3 clone design, I would be very surprised if a i3 MK2 wouldn't work

Can you please include the STL for the X endstop switch. Thanks.

Added the STL for the X endstop.
So far I'm still very happy with this set-up

Hey I think you uploaded the wrong belt holder. The one on the picture looks different :)

There are 2 versions,
The original one with minor changes is for a 20 teeth pulley and pulley wheel (X_Belt_Holder_Mod)
The one in the picture is a changed design because I use 16 teeth on the motor and the idler (X_Belt_Holder_16)

Thank you for sharing.
You know you sort of ruined the Extruder by placing the two fingerscrews on top? By doing so, you can't use the top plate to rest your thumb agains while you pull up in the lower tensioner with two other fingers!!
One of the major advantages of this extruder is that you never need to adjust the idler tension (the screws) once you have it set. Ie. you just set it once and never have to fiddle with it again!

removed the thumbscrews and updated the appropriate photo's ;-)

Looking good! :)

You are right. Initially I assumed I needed some adjustment hence the added thumbscrews. In reality I never needed to adjust the setting. I can still open to extruder with one hand but without the thumbscrews it's easer.
Thanks for the tip. I will remove the thumbscrews.
Great design by the way. I was able to successfully print with NinjaFlex!!
You may want to consider adjusting the inside of the main peace. I had to do a fair amount of "cleaning" to the main body to have the 22mm bearing run freely when pressed against the filament.

What material did you use to print the extruder? I practically never have to clean out anything and only around the filament channel. I havn't ever had problems with the idler bearing not being able to run freely!

Nice about Ninjaflex. What kind was it? (hardness, shore number). Printing flexible was a goal for me, but I find that the most soft flexible isn't good in the extruder, due to bowden, but semiflex works fine. I prefer to print in 2.85/3mm for flexibles though.

Notice I made a version 4 of this extruder a little while back? Main functionality is the same, but I'm using smaller bearings and the Idler adjustment has been moved down alongside the extruder, so it's much more compact.

Belted Extruder v4
by dintid

I will try the v4. Keep you posted at https://www.thingiverse.com/thing:2527297

Belted Extruder v4
by dintid

I printed in PLA at 100%. The 1.75 version. It was not really cleanup but I had to remove a slice of the body. After that it was OK.
I'm not at my desk so I can't check the exact version but the flexible filament was very soft. Printed at 25mm but it came out great :-)

Just to be sure I understand correctly. The Idler bearing was hitting the body of the extruder before the filament?

I guess it's because you printed at 100%. There is default 10-20% (or more) infill overlap on infill and border = overextrusion by default. Doing 100% infill makes for no room for that extra material but outwards.

Thanks for your respons. This could be the explanation. I'm more than happy with the end result.

Always happy to help. I run my overlap at 5% on all my machines. Shouldn't really be needed to use more than this on a well calibrated machine.