@rmd6502 how many print hours are on your machine? Have you replaced any of the soft parts (bowden tube, TFM coupler). This looks more like an extrusion issue than an alignment one.
Wear on the spacers could happen--mostly due to heat--but it's uncommon since the spacers aren't particularly close to the bed.
True, lots- I replaced the tfm coupler and the bowden tube, to no avail.
Edited by rmd6502
Is your rear fan running? Filament will swell and fail to extrude if it's not running.
Yeah I hear it above 160c or so
So discovered the runtime menu, I've got 475 hours of runtime. I heated the head up to 210, confirmed the fan was running, extruded 10mm and noted that only 7mm went through. I set materials.txt to give 120% flow rate, which really didn't make any difference to the underextrusion. What's weird is the underextrusion seems to be primarily the infill, walls seem okay. I've tried swapping out the print nozzle, and multiple cold pulls with nylon filament.
Nothing seems to work.
You can try to remove the nozzle and the bowden from the feeder. Then try when you push the filament manually through the bowden and check if you feel some resistance.
Another idea is your feeder, clean it and take a look on the knurled wheels. Are they ok?
Have you printed abrasive materials?
The play on your axles is not the reason for your underextrusion.
What about your nozzle? Is it clean inside? Do some hot/cold pulls or if you have another one, try to replace it.
And last question, how fast do you print? Infill is normally printed faster than the walls, so when you say walls are ok, but infill not, maybe you print too fast or too cold for the selected speed?
1
Yeah, was able to fix the play pretty easily by loosening the belt pulleys and sliding them (as symmetrically as possible obvs). I figured the play wasn't the problem, but having tried everything else (see above) I was getting desperate. The feeder is clean, no wear line on the knurled wheel - only printed PLA, and a little bit of PETG and even less ABS.
I'll try slowing down my print speed settings, and recheck the hot end and nozzle.
Okay, 0.2 layer height, 200C, 50mm/s print speed, same spongy underextruded infill. I guess next step is to pull off the nozzle and see what's in there.
Blasted everything out with a 325C SMD hot air rework station - I could see all the way through the nozzle. Same settings, same result.
10 hours ago, Smithy said:You can try to remove the nozzle and the bowden from the feeder. Then try when you push the filament manually through the bowden and check if you feel some resistance.
Have you checked this as well?
Tried that, filament seemed to move smoothly through the bowden and hot end when I tried pushing it with my fingers.
Two interesting things I noticed though:
1. When I pulled the filament out, probably about 10-15mm (no steppers in my fingers) it would become very hard to push it back through the hot end, the filament would form a knob at the end.
2. I noted that what was coming out of the nozzle seemed wider than .4mm, measured with my micrometer at about .65mm! That would certainly explain underextrusion.
The first issue might be that I pulled it out too far, the fan is definitely running on the hot end so I wonder if that's something I should look into.
For the second, I swapped in the .25mm nozzle and verified that the filament comes out at .25mm, will try a print and see if that's any better.
Interesting observation.
Do you have a spare .4 nozzle too?
Alas, no, but if the .25 test works out I’ll buy one
👍
I had exactly the same problem with the underextrusion for weeks on 4 printers, making them more or less unusable. I tried everything, I replaced a lot of parts, but nothing would work. I really was about to throw these machines out of the window...
Yesterday I had the idea to test an other version of Cura. I downloaded v 4.5, sliced the model with the exact same settings and first I noticed that the print time was 15:02h (v 4.5) compared to 15:46h (v 4.7). Right now, I am about 12h into the print on 2 machines and none of the problems with underextrusion have appeared to this point.
So make sure to test an older version of Cura. Maybe/hopefully it solves your problem as well. Good luck!
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fbrc8-erin 272
Can you clarify what you mean about calibrating the printhead? Are you looking to check the alignment of your axles and check for play? I've got a guide here.
Bowden tube and couplers are the top things I usually replace. With that much runtime on the belts though, you may want to replace those as well. I usually find they need it between about 3k and 4k print hours depending on the printing environment. I've got a guide for that here. If you're seeing a lot of black dust building up on top of your XY motors or the belts have gotten noisy, it's time to replace them.
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rmd6502 0
I found this post from a google search. I have an Ultimaker 2 extended + and there is quite a bit of play in both Y axis axles, which I suspect is causing my uneven extrusion problems (photo attached). The article Nobulun referenced just says "If there is play on the axles, it is recommended to calibrate the printhead", but there's no reference to how to do that.
I'll check your guides on aligning the axles and checking the belts, tho I suspect there's wear on the axle spacers.
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