Keep getting a filament stuck message on my MK4S  

RE: Keep getting a filament stuck message on my MK4S

My MK 4S has started to experience stuck filament. I am using PLA. I am able to unload it and get started again, however, it will get stuck again and stop again. I am new to using the MK 4S and would like some Advice on steps I can take to try to minimize this from happening. 

RE: Keep getting a filament stuck message on my MK4S

We have same issue on Prusa MK4.

In our case the problem with Prusa Nozzle brass. Need to replace it.

We tried to clean the nozzle in some ways but melted filament glogged inside the nozzle brass and the stepper motor of extruder started knoking.

RE: Keep getting a filament stuck message on my MK4S

Same here. My very first print on my factory-assembled MK4S (the benchy using the enclosed Prusa PLA) ran into it once. Second print (insane benchy) got through without it. My third print, using Prusament PETG hit it repeatedly. After the third or fourth time, I disabled the stuck filament sensor via the tuning settings, but soon noticed that the printer had stopped extruding halfway through a layer. So, the filament was actually getting stuck instead of it being a false positive. I was able to save the print by using the tuning settings to force a filament change (simply re-inserting the same filament) and re-enabled the stuck filament sensor. It was able to finish out the print afterwards.

I may try using the non-high-flow nozzle profile to see if that has an effect... although that will slow the print down, I imagine.

RE: Keep getting a filament stuck message on my MK4S

Anyone have a suggestion???  Here are 4 people that have the same issue.  Maybe someone could offer help  ? 

RE: Keep getting a filament stuck message on my MK4S

I started a chat with Prusa support last night while the print I was running had something like 7 stuck filament errors in a single layer. The first troubleshooting step they wanted was a picture of the print. Then they wanted pictures of the top of the hotend where the grub screws are, and one underneath the hotend where the nozzle enters the heater block. The first one was easy. I just paused the print, snapped it and sent it off. He said it looked fine. The second one would require me to abort the print, which I wasn't really interested in doing, because it reached a part of the model where it seemed to be printing fine. The support person said no problem, to rejoin the chat later if I had time to take that photo. After the print, I realized that to get the photo of the nozzle entering the heatblock, I'd have to at least take off the silicone sock, and likely the entire fan shroud. Not sure I wanted to do that, so I called it a night.

While that print was going on, I did use the tuning options to raise the nozzle temperatures by about 10c.  I'm not sure if that's why the print was able to finish OK. I just printed the MK4S nozzle changing tool from Printables, after having bumped up the nozzle temperature from the Prusament PET-G profile by 5c. It turned out fine with no stuck filament errors.

I think I've been mainly getting these errors during parts of prints where there are long extrusions. The print I was doing last night had 5 layers of a fairly large base. That's the part where I was getting the stuck filament errors. Afterwards, it was printing walls around the perimeter using a sort of corrugated pattern, so lots of direction changes. I'm right now printing another model with in PET-G with the same several large solid layers using the 5 degree C bump from the factory setting.  It's made it through the second layer (which was where I had 7 or so stuck filament errors) so far. So, maybe try increasing the nozzle temps to see if that helps.

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I wasn't having an issue before upgrading to the MK4S, but then I kept getting the message at least once every time I printed. I disabled the stuck filament detection and it's now working perfectly.

RE: Keep getting a filament stuck message on my MK4S

I'm having this issue as well:

https://forum.prusa3d.com/forum/english-forum-original-prusa-i3-mk4s-assembly-and-first-prints-troubleshooting/first-few-prints-were-perfect-now-stuck-filament-detected-every-few-seconds/#post-722488

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Same error message. going to take apart and rebuild entire hotend and see if there is something else I can figure out. I am using it with the MMU3 and keep getting the filament error."pfsensor too early", because it says there is fillament still in the extruder when there is not. 

RE: Keep getting a filament stuck message on my MK4S

I have had this problem since I installed the HF nozzle on my MK4S.

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J'ai également été confronté à ce problème. Depuis que j'ai retiré le guide filaments du support plus de problèmes. J'ai constaté que cela ce produisait surtout vers les extrémités du plateau, le guide filaments crée une contrainte et tire le filament de l'extrudeur ce qui génère l'erreur. J'en ai aussi profité pour resserrer les vis de l'idler,depuis tout fonctionne parfaitement 

RE: Keep getting a filament stuck message on my MK4S

I just upgraded a working MK4 to a MK4S and I keep getting this error now, too.  I literally never saw this error before the upgrade and now I can't get through a print without it.  This is maddening.  I'm using the same nozzle as before - I have the MMU3 installed, and the instructions recommended retaining the same nozzle. 

Initially, I thought this was a filament problem, or changing filament problem.  I had been using Prusment PCCF and switched to PLA.  I thought I was getting stuck filament due to the change.  I heated the nozzle to 285C and cleaned it out, then I purged a bunch of white PLA through the nozzle until I couldn't see anymore black PCCF specks.  Maybe this is still the issue, I don't know, but I did this filament change on the MK4 without issue.

I did update the firmware to the latest.  I was using the previous revision when the printer was an MK4.  This error feels like a firmware issue - the hardware in my case (the extruder) is exactly the same.

Starting to regret getting the MK4S

OK, so, an update on my fighting this issue.

TLDR: I'm planning on returning this thing for a refund.

I had several prints on the structural setting that went well. But, of course, these run much slower than the advertised print speed for the MK4S.

I was able to get a few prints in on the speed setting without many stuck filament issues. But these were all smaller pieces that had short passes, rather than long extrusions. I hit a few isolated stuck filaments in some prints, but upped the nozzle temperature a few degrees and they didn't reoccur.

Today I decided to start printing a rugged container which had the same sort of large base that caused me issues in the past. I decided to use Jessie PET-G, because I had the color I wanted, and I'd had good luck using it with my MK3S. I made sure to slice the model using the Jessie PET-G filament preset. Based on one of  recent posts in this thread, I didn't load the filament through the filament guide, just in case that was the issue (spoiler alert: it wasn't).

Attempt #1 failed on the second layer not because of the stuck filament issue, but because for some reason the second layer started getting ripped up. It was isolated to a specific patch of the print bed, instead of being the entire extrusion.  It looked similar to the effect of having the live-Z too low on a first layer... but the first layer was perfect. Aborted that print.

Attempt #2: shortly into the second layer, I started getting stuck filaments again.  First off, I just have to say how obnoxious the process of clearing these are. I have to confirm three steps, including the fact that I have inserted the filament, which seems absurd. Why not just unload, then reload when it detects the filament as usual? Second, I had noticed in the past that even when I use tweezers or pliers to clear the ooze from the nozzle before confirming the filament color so it can resume printing, I'd end up with blobs on the print. Now, during the 4 or 5 or so stuck filaments I hit, twice I saw that after cleared the nozzle and   confirmed the filament had extruded, it when ahead and extruded more filament before moving back to print, thus ensuring a blob on the print! Why? This print finally failed after the 5th or so stuck filament error. After confirming that the filament had extruded, the print resumed. A few minutes later when I looked over at the printer, I realized it had stopped extruding filament. So, it had the exact problem the stuck filament feature was supposed to solve. Great. Aborted that print.

Next, I checked to see if there was firmware update. To my surprise, there was. My experience with the MK3S made me expect that I'd get nagged when there was a new firmware, given the difficulty I had disabling those nags back when the firmware updates were incompatible with the Revo Six hotend I had in the printed. So I went ahead and updated hoping that might improve things.

Attempt #3:  I got a stuck filament error just after the printer started the second layer. I did the unload/reload again, and immediately hit the tune option in hopes of  raising the nozzle temperature to see if that would help. But before I could even get that far (literally seconds after I  resumed the print) it got the error again, which kicked me off the nozzle temp screen and brought me back to the stuck filament error screen. At that point I just ragequit the print, because I'd wasted HOURS of my time at this point getting this thing to simply do its job.

I'm really just done with this. This isn't a cheap printer. I paid to have this thing assembled to ensure it was done right. I suspect if I reach out again to Prusa support, the debug steps would eventually lead me to having to tear into the hotend or something similar. At which point, you have to wonder why I had paid to have the thing assembled in the first place. 

I bought the MK4S because my MK3S is currently down with an apparent blob within the hotend, which is the latest of a bunch of issues that had cropped up. I'd hoped the MK4S would be a ready-to-go and much faster way of getting back up and printing. That appears to not be the case.

RE: Keep getting a filament stuck message on my MK4S

I finally disabled my stuck detection too.  It has solved my problem.   

RE: Keep getting a filament stuck message on my MK4S

For me, that doesn't work. Turning it off results in the hotend eventually stopping extruding because it does apparently get stuck.

RE: Keep getting a filament stuck message on my MK4S

Just finished my MK4S upgrade yesterday, and now I’m getting this error as well. I’m printing out a 2x4 Gridfinity bin. The first time was with PLA, and the print had warped a bit. After doing the unload/reload, I heard the nozzle scraping lightly on the print, so I figured that was it. Switched to PETG since that sticks to the  sheet particularly well. But I ran into the same error at a similar point, and there was no warping (and hence scraping) this time. 

Tomorrow I’ll try a different print mode (this was 0.25 speed) and see what happens. 

But like others, I never had this error before the upgrade. 

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I ended up replacing the nozzle - it's been about two weeks with no further re-occurrences.

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I recently had a similar situation. after countless changing nozzle/filament with no success,  I spoke eventually with Prusa support. Off-course I need to do some more (re) testing with them, but after severall attempts they eventually agreed on changing the extruder motor with a new one.  And now the problem is gone.

So double check if it's not the extruder (In mine case this was very difficult, because the motor was turning most of the time, but sometimes it stalls for a very short period, and then started turning again.) 

to be compleet: Mine prusa mk4 was sitting in the official enclosure.

RE: Keep getting a filament stuck message on my MK4S

Just upgraded to MK4s as well and now getting stuck filament errors on large flat prints (small ones seemed fine).

Will try to disable the stuck print detection - far from ideal!

Chris

RE: Keep getting a filament stuck message on my MK4S

Hi,

Well the stuck filament didn't help ... seems like the nozzle is somehow ripping up what its already printed.

Just to prove it seems something to do with long prints I printed the gargoyle fine.