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Extruder idler tension  

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towlerg
(@towlerg)
Noble Member
Extruder idler tension

I don't have a Prusa printer but is there any systematic way to determine an appropriate tension for any given material. What I do at present is a case of if it aint bust etc. it just worked when I recieved the printer and have never adjusted it - that just feels wrong. I tried to add a filament run out sensor but the extra friction (I assume) affected quality.

This topic was modified 2 months ago by towlerg
Posted : 28/07/2021 1:54 pm
BogdanH
(@bogdanh)
Reputable Member

When adjusting filament extruder tension, there's no way to know in forward if tension is appropriate or not -it's all about feeling and common sense (depending on filament and extruder type/construction).
I usually start with lower tension (just enough for gears to grab the filament). I check that, by loading few centimeters of filament and then try to pull it back. If I can pull out filament easily, then I increase tension a bit. Indicator of too big tension can be too deep gear traces on filament at extruder output -some traces are always visible, though.
Before I start with actual print, I always check with extruder calibration. Needless to say, that extruder calibration must be done on heated hotend (proper temp. for particular filament), so filament actually melts trough nozzle (as in actual print). I say that, because I saw some video(s), where extruder calibration was done without filament going into print head -no need to explain what that's wrong.
If I get correct calibration result (without some "strange" noise from extruder) then it's time for small test print.

Others might have different/better approach.

Mini+ with Bondtech upgrade & modified firmware...
Posted : 28/07/2021 2:42 pm
bobstro
(@bobstro)
Illustrious Member
I just go by feel (on non-Prusa extruder)

It really depends on your extruder. I've got one of the clone extruders on my Sidewinder and it's pure guesswork. I just eject the filament and give it a look now and then. If it's gouged up, I back the tension out a bit.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 28/07/2021 2:43 pm
cwbullet
(@cwbullet)
Illustrious Member
Idler tension

 

Posted by: @bobstro

It really depends on your extruder. I've got one of the clone extruders on my Sidewinder and it's pure guesswork. I just eject the filament and give it a look now and then. If it's gouged up, I back the tension out a bit.

The same is true with one Bondtech I have and a few fo the Chinese clones.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 28/07/2021 2:46 pm
towlerg
(@towlerg)
Noble Member
Topic starter answered:
How much is enough

@cwbullet and @bobstrow  I kindda thought thats what you'd say. Can I infer from your remarks that you'd be looking for minimum pressure consistant reliable filament feed. Anybody know what would be the consiquence of too much pressure? 

Posted : 28/07/2021 9:06 pm
cwbullet
(@cwbullet)
Illustrious Member
grind

For me, too much pressure leads to clicking and grinding of filament.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 29/07/2021 1:15 am
towlerg liked
towlerg
(@towlerg)
Noble Member
Topic starter answered:
Thanks

Thanks

Posted : 30/07/2021 1:08 pm
Lichtjaeger
(@lichtjaeger)
Noble Member
"Improve your prints" video

Step 3 shows how to calibrate the tension correctly.

Posted : 30/07/2021 4:19 pm
towlerg liked
towlerg
(@towlerg)
Noble Member
Topic starter answered:
thanks for the vid

@lichtjaeger.

Thanks for the video. So we're going for minimum pressure.

Posted : 31/07/2021 2:46 pm
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