How to find correct extruder tension (mk3)?
I find it really hard, to find out, what the correct tension of the extruder spring screws is.
If they are too loose, the extruder makes loud clicks and no filament is extruded.
If they are too tight, it's the same.
There seems to be a relation to the printing-speed, too. This seems to be obvious. The higher the printing-speed is, the faster has filament to be transported, I assume.
I have assembled my mk3-kit since 3 days, but I was not able, to find a tension, that works through a whole sprint.
I sliced with prusa-control and with simplify3d. In simplify3d I used the mk2s and the mk3 profile.
With my mk2s it was no problem, to find the correct tension, at all.
Does anybode have any good tips, how I should proceed?
Re: How to find correct extruder tension (mk3)?
With no filament I screw the screws in until they just touch the springs and leave them there, when the filament is inserted, the trapdoor on the right moves out a little, and tensions the springs just right!
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: How to find correct extruder tension (mk3)?
Thanks for your answer Joan.
It sounds, as if you are writing about the mk2, don‘t you?
At least with my mk2s, I do it exactly, like you described it. But on the mk3 it‘s different.
After my first experiences, I am not toooo happy with the new extruder, at least at the moment ....
Re: How to find correct extruder tension (mk3)?
I tension my Mk2.5 the same way I did the Mk2. Manually feed the filament until it gets all the way through the gears, then back it out. Hold the filament up to the light and adjust until the teeth marks are about 10%-15% into the filament and the filament isn't deformed (squished).
I've actually found the Bondtech gears to be very forgiving with the idler tension. I switched from PETG to PLA and forgot to adjust the idler and didn't get any extruder skipping, even though the gears barely bit into the PLA.
Re: How to find correct extruder tension (mk3)?
yes, but unfortunately the mk3 extruder is not as forgiving as the mk2(s) one
on my mk3 it even differs, if I use three different PLAs from three different vendors.
One PLA, that works without any problem on the mk2s, does not work on the mk3 at all ....
Re: How to find correct extruder tension (mk3)?
The Mk2.5 extruder is basically the same as the Mk3 one. Check to make sure your idler gear can spin freely when it's not connected to the motor's gear and that there isn't anything blocking movement on either of them. Maybe also check and make sure there isn't too much resistance for the filament when it goes through the PTFE tubes.
Re: How to find correct extruder tension (mk3)?
@Zinga, I should have read more carefully 😉
Thank you, I will try this.
Re: How to find correct extruder tension (mk3)?
Hi Wolfgang, I was talking Mk3.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: How to find correct extruder tension (mk3)?
Hi Joan,
ok, then I have not understood, what you have meant with "I screw the screws in until they just touch the springs" and have to think a about it a bit more ....
Re: How to find correct extruder tension (mk3)?
Hi Wolfgand
with the fillament unloaded
if you use the ball end allen key
and unscrew the tension screws all of the way,
then using the alen key gently screw one of the screws back in, you should notice that the screwing effort increases, as the screw starts compressing the spring. this is where I set my screws, having done one, do the other screw the same way...
then when you insert the filament the pressure roller causes the springs to compress a little more, and provide adequate tension for driving the filament.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: How to find correct extruder tension (mk3)?
I screw them in until on the other side they are flush with the outside of the nuts.
Re: How to find correct extruder tension (mk3)?
Thank you Joan! I was having trouble with my new Prusa i3 MK3 Kit. I was often experiencing extruder "clicking" on first layers and long edges. I followed your advice and found that I had overtightened one of these screws. I've had 2 successful prints since I made this change. Thanks!
Re: How to find correct extruder tension (mk3)?
Is it normally that the extruder tension screws looses after about 24 h printing?
I was printing a new object, all objects before this printed very well. Then the filament stopped to extruding mid print. I thought it was clogged nozzle but it was the tension extruder screw that became loose! The screws almost out!
Prusa MK3S MMU2S
Re: How to find correct extruder tension (mk3)?
felix, the springs on those screws should keep tension on the idler but if your filament has a variable diameter you might have the idler set just fine for plastic that is 1.79mm in diameter at the start of the print (which is within the standard tolerance of ±0.05mm) but by mid roll the diameter may have shrunk to 1.71mm (still within that ±0.05mm) and that change can cause slippage... while the standard in the industry as a whole is still ±0.05mm the quality makers have moved to ±0.03mm or ±0.02mm An Prusament is now on the last rolls I have bought at ±0.015mm it is a key improvement and I no longer buy filament that is not ±0.03mm or better.
RE: How to find correct extruder tension (mk3)?
Same problem here. My latest mad experiment is to run the machine at double speed. This may keep heat from going up the filament, softening it.