PRUSA MK3S+ extrusion troubleshooting (I've tried almost everything!)
Hi everyone, I'd like to ask for your collective expertise on troubleshooting extrusion problems on my MK3S+.
Symptoms:
- Intermittent lack of extrusion or more rarely under extrusion
- Motor makes a clicking noise when this happens and seems to "jump back"
- No filament comes out of the nozzle most of the time
- Restarting the print sometimes repeats with the same problem, sometimes does not
- There doesn't seem to be filament grinding on the gears
What I've tried so far to address each possible issue:
- Greasing the extruder gears (gears binding)
- Replacing the hotend PTFE tube (friction in PTFE tube)
- Using different PLA filaments (not filament specific)
- Tightened extruder gear grub screw (loose extruder gear)
- Re-aligning the extruder gears (friction in filament path)
- Cold pulls (clogged nozzle)
- Running cleaning filament through the nozzle (partially clogged nozzle)
Other info:
- I'm using an obxidian 0.4mm nozzle that I haven't had to change in 10+ months. Doesn't appear to have any wear on it.
- I only run PLA on this printer
- I'm using gcode that I've successfully printed 100+ times for 2 years (this is not an exaggeration)
- The extruder motor grabs filament with good force when the printer is running a successful print
- Hotend fan is clean and blowing air but I don't know if it's blowing enough air (possible heat creep?)
It's baffling because it doesn't happen all the time and I can't isolate any other problems. If anyone has ideas, I'd love to hear it!
This sounds like a filament related problem. Some need adjustments to the extruder idler, some pigments and inclusions are associated with more frequent (partial) clogging.
Check the diameter of the filament you are using - take a few measurement along a couple of meters and average them; it's rare these days but undersize filament needs the extruder idler to be tightened and the actual value to be entered in slicer - so the gcode for that reel may be a little different. Even rarer is surface dust/contamination building up inside the extruder and clogging the Bondtech gears - some filaments do deteriorate if kept too long.
Was there any visible debris in those cold-pulls?
Cheerio,
RE:
The answer to Diem's question about debris on cold pulls would be a good clue. Could you show us some of these cold pulls ?
Anyway, the fact that the problem occurs with different PLAs seems to indicate that the issue is that particular nozzle. Ten moths of continuous use can clog progressively the interior of the nozzle without leaving any traces outside. I can be wrong of course, but using a different nozzle would tell us if the problem is that. I'd try an ordinary brass one. Obxidians and similar models made from a brass/copper body and hardened steel tips sometimes are more prone to partial clogs. Because of the internal geometry, the molten filament path isn't as straight and smooth as on regular unibody nozzles.
Another possibility, albeit less likely, is heat creep. Are you printing in an enclosure ?, What ambient (or enclosure ) temperatures do you have ?.
RE: PRUSA MK3S+ extrusion troubleshooting (I've tried almost everything!)
Hi Diem, those are good points, I will check my filament diameter when I’m off work today and I’ll do a cold pull for a photo next time a clog happens. I don’t recall any debris but I’ll take another look. For the moment, it’s been running 24 hours without a clog.
Thanks!
RE: PRUSA MK3S+ extrusion troubleshooting (I've tried almost everything!)
Hi Artur5, I have been wondering about the nozzle as well, but I’m loathe to change it because it’s such a hassle to recalibrate z level and there doesn’t seem to be anything wrong with it. But I also have a gammamaster I can swap out so I’ll try that - I’ve used up all my brass nozzles.
I’m printing without an enclosure but now that you’ve mentioned it, it has been cold recently. I wonder if low ambient temp would be causing problems?
RE: PRUSA MK3S+ extrusion troubleshooting (I've tried almost everything!)
I replaced the hotend fan and I've had 3 successful prints so far, about 10 hours print time. It seems like that fan was on the way out and it was causing heat creep which prevented filament from reaching the nozzle.
RE: PRUSA MK3S+ extrusion troubleshooting (I've tried almost everything!)
Hi @aldabest, how is the situation? Did replacing the fan really help?
I am running into just the same issue as you are, did all the steps from https://help.prusa3d.com/article/under-extrusion_2007 and more and nothing helped. The main difference is that this started yesterday with maybe 20 underextruded final layers in an otherwise perfect print. And after that I was not able to ever get past the first 10 or so layers max.
I'll try the fan replacement next if I can find one that fits.
I am going to upgrade to MK4S and hopefully with the Nextruder things will be better, but until then I do still have some prints on the backlog...
RE: PRUSA MK3S+ extrusion troubleshooting (I've tried almost everything!)
Unfortunately the problem still persists. I think I need a new extruder motor. If that doesn’t fix it, then a new board is probably the last resort. Were you able to get your printer working in the last week?