Keep getting a filament stuck message on my MK4S  

RE: Keep getting a filament stuck message on my MK4S

Hello all!

I am working on an enclosure now. The last print showed extreme warping

I suspect somehow there is some draft hitting it enough. Despite brim and a clean sheet I get warps if I print over the whole sheet.

Certainly environmental impact. I rotated the print around to notice that it is much worse in other spots.

RE: Keep getting a filament stuck message on my MK4S

Hi, not sure if my solution is relevant to others but...

Short description: 
Unload filament, crank up the nozzle temp to its max and see what happens.
A small PETG droplet fell to the build plate.. seems the "unload filament" process left a very small amount of PETG in the nozzle. Just enough to cause a sensor problem but not enough t0 block PLA flow.

Details:
I have an MK4S kit, no enclosure, 04mm HF nozzle, built in October 2024 and has been running practically non-stop with PLA.
I recently started printing in PETG, swapping back and forth between PLA and PETG. This weekend I went back the Prusament PETG to print a mod in orange, When I switched back to PLA, my next print had some very minor nozzle ripping of the the surface. I attempted to reprint (Multiboard large bin) several times, but repeatedly received "stuck filament" notifications within minutes of starting each print.  Assuming the PETG swap was mostly likely contributing to the issue, I tried heating the nozzle, which eliminated the stuck filament problem.

This issue notwithstanding, I have absolutely no regret in my purchase of the MK4S... not even when my doggo absconded and chewed up some of my parts during the build. But that was all my fault for attempting to multitask, lesson learned 🤔 ... again 😆 

Anywhoo, hope this info helps others.

Heating the nozzle to its max allowed whatever PETG that remained in the nozzle to drip out.
Printer is back in action, completing the failed print as well as other large prints yesterday (1/13/2025)

RE: Keep getting a filament stuck message on my MK4S

I had exactly the same experience after upgrading from Mk4 to Mk4s. My first attempt was to change back to the Mk4 nozzle. During the change I noticed that the nozzle was a bit loose. So I tightened it. Since then it seems to work fine. But take it with a grain of salt as the repair is quite fresh (I did it today).

Next steps for me is to buy moment key to tighten it in more precious way and monitor situation. If I have any new findings I will keep the forum informed.

RE: Keep getting a filament stuck message on my MK4S

Same here MK4s upgrade. Turned stuck filament off and prints finish ok. 

RE:

Keeped happening to me on random occasions, my suspicion was that the filament was bad.. but that's not the case
Switched for the MK4S from the 0.4 HF to the 0.6 HF nozzle.

The following things helped me to fix it:
- Increased Nozzle Temp by 10 degree for the normal layers, first layer stayed the same. The temperature dropped after the first few layers when the printer got faster, so watch the temp
- avoid to use the "Grid" infill, Honeycomb works fine. Had the feeling that the "bumping" could trigger the error
- put my spool (esun pla) on rollers instead of the holder in the orginal prusa case

I also printed some tests too see if the printer is skewed or I get some errors after Z > 4mm, but everything was ok.
Printing now the third big model, no problem

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RE: Keep getting a filament stuck message on my MK4S

I have a enclosure now. I am waiting for PETG. A full box of PLA printed perfectly like nobodys business.

So certainly there are a multitude of factors. Now with Prusa Core One there is a good upgrade path for a fixed enclosure too.

Either way I will let you know how the next PETG prints will go.

RE: Keep getting a filament stuck message on my MK4S

I’m almost certain my issue with this was environmental. It didn’t start until after the upgrade to MK4S, but I also ordered that upgrade kit as part of my Black Friday order; right when it started to cool down as we went into December. And my printer was in the garage. I moved it into my office a couple weeks ago and haven’t had an issue since.

I said almost certain because I also had an x-axis linear bearing that was clicking during travel at the same time. I took it off and cleaned it out and it stopped clicking, but didn’t have any large prints after that before moving it into the office, so can’t be sure it wasn’t involved.

RE:

I too am having this issue on a new MK4S Kit, particularly when the .2mm speed profile (.4mm HF nozzle) is selected in PrusaSlicer and I'm printing a large object with straight, fast lines, namely a Gridfinity bin. I get through printing the square feet no problem, but once the printer starts printing the floor of the bin, I get a stuck filament error continually.

I'm using PLA but was previously using ASA for another project. 

I tried testing without a PTFE, pulling a bunch of filament off the spool and letting it print to ensure there wasn't drag from my drybox, bumped the temperature up by 15C (now printing PLA @ 220, when I've printed it forever at 205 on my MK3S+ without issue), tried multiple cold pulls and cleaning with the supplied needle.

Continued getting the error so I disassembled the heater block, removed the nozzle, and blasted it with my MAPP Gas torch until any residual filament was liquified and dripped out, which quite a bit did come out. Let it cool, reinstalled, and am reprinting the bin, will report back shortly.

RE: Keep getting a filament stuck message on my MK4S

Just bought a prebuilt Mk4s and had this issue with a print that occupied almost the entire build plate with third party PETG, where on half-ish of layer 3 it kept getting this error, went back and forth once after I reloaded the filament, then got the error again. I did notice there were a lot of zits (if that's the right word) on the first layer, but I also dumbly used the default PETG profile instead of the profile I used in my previous printer with orca slicer (couldn't be bothered to remake it in prusaslicer lol), and now noticed the default generic PETG profile uses 240 nozzle temp and 85 bed temp, while the one I used based on the filament setting used 260 / 70, so that could be the difference.

RE: Keep getting a filament stuck message on my MK4S

I had this same issue.  Tried numerous fixes.   Basically no issues until 4S upgrade.  I took the extruder out and it turns out the set screws had actually been tightened too tight and the extruder nozzle (Bondtech 0.4mm CHT coming with 4S) had been deformed and crushed.  I ordered a new nozzle.  Hopefully that fixes the issue.

RE: Keep getting a filament stuck message on my MK4S

I've had the same problem since upgrading to MK4s. Before, with the MK4, everything always worked. Now I can hardly print a part without the message below coming up and having to re-feed the filament. The message says that I should calibrate the filament sensor. I've done that several times, but it didn't help. Based on the number of messages in this forum, this seems to be a real problem that Prusa can't get under control...

RE: Keep getting a filament stuck message on my MK4S

Your fix was a new nozzle, as was mine. Prusa support sent me another one and it resolved the issue. For some reason I can’t edit my original post. 

RE: Keep getting a filament stuck message on my MK4S

Posted by: @nokar-protofab

Your fix was a new nozzle, as was mine. Prusa support sent me another one and it resolved the issue. For some reason I can’t edit my original post. 

Unfortunately Spammers used to edit posts that had passed moderation. so that they could add spam links... this caused Prusa to reduce the duration of editing capability. 

regards Joan

RE: Keep getting a filament stuck message on my MK4S

Welp, hello again, folks. I thought my issue was resolved with a new nozzle....it was not. This is now the 6th time I'm contacting Prusa support, with a 20-25 minute wait each time. The time invested in fixing this BRAND NEW machine is becoming a huge burden. 

First it was clicking bearings (didn't lose any balls during assembly), then it was spinning nuts in the y-belt holder and heat bed cover and now it's an issue with "stuck filament" that has been plaguing me since the start when printing large items and the printer is moving in straight-fast lines. 

I'm at a loss at this point. 

RE: Keep getting a filament stuck message on my MK4S

I've had quite a few chats with support about this now. (Same issues as most of you here. Filament Stuck Error -> Ripped layers -> Rattling / Skipping sounds when (un-)loading Filament or purging. It gets worse over time. At first they solved it by sending a new motor. However the problem came back after a few weeks. So now their suggestion is to try yet another motor but with Prusament, suggesting the issue may be with the Filaments (settings). I honestly very much doubt it, given my Filaments worked for many months flawlessly, but will report back in a month or so how it went.

RE: Keep getting a filament stuck message on my MK4S

I've had this problem for a while now.  Mostly been printing a lot of bins of various sizes.  I noticed that the larger ones tend to have more of a problem.  In fact, when I print the 4x4" ones this problem starts at the same point in the print.  I have to go through the process about 4 or 5 times, and usually after that the print finishes without issues.  Also, on the larger prints I have issues on the side walls that looks almost as if the nozzle is in the wrong location and stringing on the sides of the wall.  I may try to increase the nozzle temp as some have suggested and see what that does.

RE: Keep getting a filament stuck message on my MK4S

I have the same problem after upgrading my MK4 to MK4S. I never saw a "stuck filament" before (three years of almost daily printing MK3 and MK4). Both printers are in a Prusa Enclosure in a warm dry room with filament kept even dryer.

I did the upgrade first without the new nozzle (standard 0.40), then with the new HF nozzle, and now with a third (also new, but 0.25) nozzle and all three have the stuck filament problem every two to three hours. Which is very annoying because I like the 0.05 layer so frequently have day(s) long prints.

I mainly use Prusament PLA and PETG.

I will try the tips from this thread like raising the temperature.

RE: Keep getting a filament stuck message on my MK4S

Updating this as I came across a post online about this exact issue and the recommendation works. 

Tighten the 6 screws on the back of the extruder 1/4-1/2 turn, I am officially no longer getting a filament stuck and homing issues in the air when trying to return Z to home. 

RE: Keep getting a filament stuck message on my MK4S

I tried a new head and that did not solve my problem. I tried higher heat but I did not like the quality. I lowered the speed to 75% and that worked great.  This was only happening when I had a large flat area to print.  It did it like clock work same exact spot each time. Lowering the speed produced a much cleaner print.  Here are some photos of my results.