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Printer stops extruding PLA

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There are a lot of information on the internet about printers that stop extruding filament, but i tried most of it with no luck, so this is my last hope before i go crazy.

So the problem is that the printer stops extruding filament through the nozzle every time i printer for over 1 hour. Every time this happens the filament is ground or very flat by rolling the filament back and forth the material feeder to the point where it stops feeding the machine because it loses grip on the filament or there is a steep curve it's too hard to roll over. I pulled out the bowden tube in the hot end to see if the problem was caused here. I could push PLA through the nozzle by hand, but i noticed there was a gap of 2-3cm between the filament end and the nozzle, so i guess the problem is with my material feeder and not a clogged nozzle. Please help me, my friends laugh at me because i spent 2k on something that does not work, but i really want to show them the power of this printer and blow their minds.

I'm printing with ultimaker filament, 30mm/s, 230c, 0.1mm layer.



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I have Ultimaker 2. The screw for adjusting the pressure on the filament is as lose as it can get, so i cant put less pressure on the filament. The flat filament you see in the picture above is when things start to go bad after the printer push the filament back and forth the feeder until it's flat and loses grip.

This is how it is when printing goes fine.



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I had exactly the same problem once. Nothing would help, until I completely took apart the extruder and cleaned it of all residual material. There might be some contamination that travels up and down the nozzle. Actually you only have to clean the nozzle and the PTFE bushing.

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I've never seen filament squeezed flat before. Never. I think I've read every post for about 2 years.

I'm thinking your feeder stepper is getting very hot and that is warming up the PLA above 50C and that is causing it to turn into clay and getting squished. I wonder if something is defective on your board that causes the feeder current to be unlimited.

I'm not sure how to test this theory. Spray the feeder with freezing spray every 60 seconds?

I guess I would use the gcode command to reduce the current to the extruder lower and lower and make sure it is very weak at 0 amps. Then I would program it to be 20% lower current and see if you can print the same print much farther along before it fails.

So to test my theory first install pronterface on a PC. It can be found here:



Then issue:

G92 E0 (this tells Marlin that the current position of extruder is already homed)

Then move the extruder a bit for fun

G0 E-10 (move to position -10mm - possibly 10 cubic mm depending on the mode)

G0 E0

Then lower the current

M907 E500 (sets max current to 500ma, default is 1250ma)

Then move it some more back and forth and try fighting the extruder - see how strong it is. Go lower and higher currents to see if it seems to be working. It might be that this part of the UM board is broken and it always goes full 2 Amps which makes it too hot.

If the M907 command seems to be setting the current properly, try lowering the current to 1Amp:

M907 E1000

Put that above command towards the top of your gcode file before putting it on the SD card and printing it. This should keep the extruder stepper much cooler.

gcode listing/explanation can be found here:


Please report back what you find!!


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That's an interesting theory. I noticed the other day that you can actually set the stepper currents in the settings menu on the printer now with the latest firmware (Maintenance -> Advanced -> Movement settings if memory serves). So that's an option if manually sending Gcodes via Pronterface seems scary.


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So alternatively set the current to 500ma, go to "move material" and move the filament a mm or so then try pulling it out. See if you are strong enough. If not try lowering to 100ma, turn stepper back on with "move material" and try again. If this isn't working then maybe your controller board is broken.

If this *is* working (if you are able to control the current) then try doing a print at 1000ma instead of the default 1250ma. If you have temp probe it would be good to test the temp of the extruder motor or the extruder "gear" (hobbed sleeve) at the begining of your print and when it is failing.


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The problem still occurs. It feels like the feeder is not feeding the nozzle fast enough or get out of sync, because when i pause the print and drag out the bowden tube the filament is 2cm inside of the tube, so it's obviously not reaching the nozzle. But with 1000ma i now was able to pull the filament and make it long enough so i could continue printing, but this is not ideal for long prints. I think this happens when there's a lot of retractions, but i might be wrong.


is this normal?


This is how it is when i pull it out after things start to fail. It might be normal just making sure.


Even though i can pull filament through the nozzle, I will try to clean it and see if it helps.


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In first picture above - yes that is completely normal. It's perfect.

In lower picture, that is what I would expect if the head was hot (over 110C). what happened is the filament was still hot as you pulled and it stretched.

In lower picture if you had let the head cool to 90C and *then* pulled you can get a mold of the nozzle. It is good to do and informative.

The problem still occurs.

Can you explain again? Does it only happen after 1 hour? Does the filament get squished a lot? As much as the first picture?

You could:

1) Try turning off retraction.

2) In retraction expert settings set the "minimal extrusion" to a much higher value. A value of .02 (default?) with travel of 4.5mm means you can travel back and forth over the same spot on the filament 4.5/.02 or 225 times. Try maybe .5mm or 1mm (8 and 4.5 times in and out of the feeder) or even 4.5 (never go back and forth on the same spot of filament more than one extra time).

I did a print with where each spot of the filament retracted 8 times. On average. It was fine. On the UM2. Same light blue filament from ultimaker. It was a 30 hour print.


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After speaking with Illuminarti about your issue I'm thinking your spring is too loose. In the top left corner of your feeder there is a hole. If you stick a (2mm?) hex wrench into there there is a screw you can turn. You want to turn it counter clockwise to make the spring tigher. Try going down one or two marks with the white indicator. Please let us know if this helps:



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Thanks for your time gr5, i really appreciate it!

The filament did not get flat at this print, but I stopped the print immediately this time so i might have saved it. On earlier prints it have kept on running for about 15-30min until i noticed it, and then the filament is ground like the first picture.

Yes it always happens after 1 hour, but it also might work for as long as 3 hours without problems if i'm lucky.

In the picture below, do you mean it's normal patterns on the filament, or that it's normal that the feeder reversing the filament this far? I did not pull in the filament on this picture.


Btw, i adjusted my retraction settings after tips in this thread.

"retraction distance to 5.5mm, and the speed to 35mm/s"



Are these settings ok? I will try without retraction and bring back the results.

edit: Didnt see your last post. I'll try that too.


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I turned on retractions again, but with factory settings and it didn't work. I get the same problem with under extrusion, but the filament is not getting flat this time. I think tightening the feeder fixed that problem.

Is my printer broken? What should i do?


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I just cleaned the nozzle so it was all clean inside the chamber and i could see through it. I did a test print with retraction setting:

"retraction distance to 4.5mm, and the speed to 25mm/s"

and cura settings


As you can see there is under extrusion all the way in the print, and after some time there is no flow at all. It feels like the nozzle is getting clogged, but how can it clog for every print!? The feeder is ticking backwards with an interval of 1sec when this happens. Could it be possible the filament snaps in the nozzle from the retractions and are hitting the small edge of the teflon or a cold piece of filament stuck in the nozzle?

Printed at 0.06mm layer height, 50mm/s print speed, 230 degrees



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I'm quite sure that will fix the problem but now you will almost never have retractions. 3mm is a LOT of extruding!

Illuminarti has fixed some printers with this issue. I believe he fixed it by adjusting feeder - moving the sleeve inward - towards the printer - and also the spring tension. I don't know if he made it looser or tighter. Also he wonders if some sleeves have different pattern (sharper? duller?).

He found that if you look at the filament carefully sometimes you have one column of diamond shaped holes and sometimes you have two columns. He thinks 2 columns are better (better grip on the filament). He only moved the sleeve a tiny amount - maybe 0.5mm?

I'm not convinced this matters.


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Thank you for your answer gr5,

I am going to aboid the test at Minimum travel: 3mm (Retraction - Expert config), now I think that it is just to much.

I am thinking that maybe the fillament is getting flat and loosing grip because of the speed that I am using,

The print speed is 50 mm/s, but because of the geometry of the part I have to lower the speed down to 20%, do you think that the speed reduction my cause that the fillament gets just too much retractions in the same area.

Other thing that I did was to change the speed from 20% (Material Flow 120%) to 85% (Material Flow 180%), I think that my afect also the fillament flatness;

I am thinking on doing the changes more gradually, and run a new test;

What you guys think.


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do you think that the speed reduction my cause that the fillament gets just too much retractions in the same area.


No. I really don't know what the problem is. Some printers do this (flatten the filament). I think printing slower won't help.

I have a theory that the stepper is so hot that it melts the PLA a little bit. But that theory is most likely wrong.


I am going to aboid the test at Minimum travel: 3mm


Well this will DEFINITELY fix your problem. But it might cause lots of stringing.


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This is what I mean about the feeder pattern on the filament



The printer that made the purple left pattern was grinding the filament flat. The filament on the right was from a working printer. The white filament was also from a working printer. Both working printers have done incredible amounts of retraction no problem - like 100,000 retractions on a single print! Like 500 meters of retractions for one print.


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Thnks gr5,

In the past I was working with material flow over 100%

For example:

- Speed 80%

Material Flow 180%

- Speed 30%

Material Flow 130%

I think that this might cause that the stepper temperature was high, and maybe the speed reduction many retractions in the same spot of the filament.

Right now I am running a test:

Going Under 100% for the material flow:

-Speed 80%

Material Flow 100%

-Speed 30%

Material Flow 70%

I also changed:

Minimum Travel: 2mm

Minimal extrusion: .1mm

I want to reduce the retraction, and also the quantity of material that the stepper is pushing, so that also its temperature is lower.


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