What is a good tension for the Prusa Mini feeder?
 
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What is a good tension for the Prusa Mini feeder?  

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VZT
 VZT
(@vzt)
New Member
What is a good tension for the Prusa Mini feeder?

Hello, the standard files on the USB print perfect on the Prusa Mini. But when I try to print one of my own models in PLA or PETG with the standard Slicer settings after about 2 layers, it keeps grinding in the feeder/extruder and it starts printing without filament. The only way to get the filamant out is to disassemble the extruder and teflon tube. And same problem also on a second brand new mini. This sort of reminds me of my old Ultimaker and why I sold it 😉

So what would be a good tension for the M3 screw (with spring) that gives the tension to the extruder gear?

Posted : 11/02/2020 1:38 pm
Sfbrain
(@sfbrain)
Estimable Member
RE: What is a good tension for the Prusa Mini feeder?

General rule of thumb is the head of the screw flush with the body.

Loosen further (slightly) for 'lumpy filaments' like woodfill and Flexi 😉 

S

Posted : 11/02/2020 5:31 pm
VZT
 VZT
(@vzt)
New Member
Topic starter answered:
RE: What is a good tension for the Prusa Mini feeder?

@steve-4

Thank you very much. I asume that is with filament loaded. In the meantime I tried different tensions, higher z-offset, and raised nozzle temperature but no result so far. I think the mini should have the double drive gears like the mk3. Or is there something not properly assembled around the nozzle? 

Posted : 11/02/2020 5:44 pm
Nameless2nd
(@nameless2nd)
Active Member
RE: What is a good tension for the Prusa Mini feeder?

Check the hotend assembly. There are problems with a gap between the PTFE tube and the heatbreak. I had problems with jams and unloading till I reassembled it properly.

Posted : 11/02/2020 8:13 pm
VZT
 VZT
(@vzt)
New Member
Topic starter answered:
RE: What is a good tension for the Prusa Mini feeder?

Got a few mental breakdowns in the meantime because of the grinding and underextrusion. But i think i made some progression. Checked and re-assembled the hotend many times. Tried to push in the filament by hand on top of the extruder and noticed it was very hard to do when the hotend temperature was lower than 230 degrees. After that i got the idea of placing a silicone sock over the hotend. Printing with Colorfabb PLA the fan was set to 100% so the hotend is having trouble to keep a good temperature! Now printing at 210 degrees...looks ok sofar...hope the print will look good tomorrow.

 

 

Posted : 24/02/2020 3:46 pm
owestermann
(@owestermann)
Active Member
RE: What is a good tension for the Prusa Mini feeder?
Posted by: @nameless2nd

Check the hotend assembly. There are problems with a gap between the PTFE tube and the heatbreak. I had problems with jams and unloading till I reassembled it properly.

Since I just asked a question here which could be caused by this: are the assembly instructions somewhere?

Thanks, Olli

Posted : 08/03/2020 11:20 am
Keksa
(@keksa)
New Member
RE: What is a good tension for the Prusa Mini feeder?
Posted by: @owestermann

Since I just asked a question here which could be caused by this: are the assembly instructions somewhere?

Thanks, Olli

Hi, I had this exact problem and chat support sent me this guide -  https://manual.prusa3d.com/Guide/How+to+change+a+hotend+PTFE+tube+-+MINI/1505 -  ignore the steps about changing the PTFE tube, just adjust the assembly. You can see how it looks when wrong at the end of this guide https://help.prusa3d.com/en/article/clicking-extruder-under-extrusion-and-clogging-mini_112011#hotend-ptfe-tube-and-heat-break

 

Posted : 08/03/2020 12:16 pm
owestermann
(@owestermann)
Active Member
RE: What is a good tension for the Prusa Mini feeder?

Yaay.. Not. Tried that. Saw the small grub screws and got up again to grab my proper Wiha allen key set (since I didn't trust the ones delivered with my MK3S).

Still rounded out the top grub screw -> No chance to follow the guide. Will check support chat :X

Posted : 08/03/2020 6:03 pm
Crawlerin
(@crawlerin)
Prominent Member
RE: What is a good tension for the Prusa Mini feeder?

@owestermann

Those should be M3 (3 x 0.5) screws, if you find some 4-6 mm long, for example for computer disk drives mount, you can replace those for some with better heads. The hex driver is easy to strip, you have to use quality 1.5 mm bit.

Posted : 09/03/2020 1:57 am
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