Keep getting a filament stuck message on my MK4S  

RE: Keep getting a filament stuck message on my MK4S

Posted by: @chris-purves

Hi,

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

This looks like Z-offset is too low.  Try setting Z-offset in PrusaSlicer to +0.04 .  Or manually raise it with LiveOffset by holding the button till it beeps, then raise it to +0.04 .  

RE: Keep getting a filament stuck message on my MK4S

This is a far bigger issue than Z offset sadly. 

RE: Keep getting a filament stuck message on my MK4S

Posted by: @faraz

I moved from an MK3S+ to an MK4S a few weeks ago, and have been having this issue from the beginning. Every print at some point pauses with the message that filament is stuck. I then have to do an unload (which happens normally) do a load (which also happens fine), and then continue with the printing. This happens both with PETG as well as PLA filaments (both Prusa filaments), and both 0.4mm as well as 0.25mm nozzles.  Any ideas on what might be causing this?

Thanks

Hi, I have been having this problem just lately. I would tell it to unload filament, then reload filament and I would manually push filament from the cassette down to the nozzle and it would load ok and go on printing then stop again and I would have to repeat the process. I changed the PTFE tube and have not had any problems since. It might be worth a try.

RE: Keep getting a filament stuck message on my MK4S

I have an ongoing conversation with support on this issue.

In the latest round of troubleshooting, I found that the stuck filament error does not occur when my enclosure doors are open. 

I'm curious.  Is anyone else running into the issue without an enclosure, or with the doors open?  Or, is everyone else that is running into the repeating stuck filament errors have an enclosure with the doors closed?

RE: Keep getting a filament stuck message on my MK4S

If you are printing PLA in an enclosure, the temperature can rise and cause poor cooling of the extruder heatsink, this can allow the filament above the heat break, to expand inside the tubing, and cause a blockage

in the image above the Green area should be kept cool by the hot end cooling fan. and the area inside the the red ring, is directly heated by the hot end heater. the small section of pipe between the red and green areas, is the heatbreak, it is designed to prevent heat getting into the green area. 
If the temperature in the Green area rises significantly due to high ambient temperature, the filament inside can raise above the Glass transition temperature and it can soften, causing the pressure from the extruder drive hobbed gear to expand the diameter of the filament and cause friction within the nozzle tube (this is often referred to as Heat Creep).
I live in England, where we do not have naturally high temperatures, but in the winter, if I use the solid fuel heater, the local temperature can be enough to cause heat creep
countries like america, Australia,  and countries along the equator, can have high ambient temperatures which may cause unexpected heat creep during day time! hours
It is important to also check for dust collection on the extruder heat sink to minimise issues. 

regards Joan

regards Joan

RE: Keep getting a filament stuck message on my MK4S

Hi Joan, thanks for the comprehensive reply, I too live in the UK and have my printer in a homemade enclosure in an outside workshop. I have a mini heater in the enclosure for winter use and I agree with you that it sometimes gets a bit warm and it never occurs when I have the door open. I will have to keep a better eye on the temperature from now on. It seems so simple when it's explained. Thanks again, Bob. 

RE: Keep getting a filament stuck message on my MK4S

Guys, there are several threads with the same/similar issue. So let me repeat my post:

Let us differentiate between the filament stuck, when no filament extruded and the filament stuck error appearing on the screen.

1. The filament stuck error is based on the loadcell filament push force monitoring so when you switch it off via the settings menu, the error should not appear. The stuck error could be recognized also at the moment the insufficient nozzle temperature, the filament pushes on the loadcell too much, which leads to filament stuck error. It does not need to be necessarily followed by a real filament stuck. 

2. the real filament stuck (filament extrusion stops) could be caused by lower than required nozzle temperature. Be aware sometimes the nozzle purge temperature could be different (set in FW) than the printing temperature (set by slicer)  so the nozzle is not heated enough. Secondary effect of this is a dent on the filament at the extruder gear position and a clicking sound.

3. Sometimes the Filament stuck error can be a false warning, sometimes can be real. I guess the FW team still should refine this function.

Note:

Printing in the case especially PLA or PETG can lead to the filament preheating before it enters the extruder gear. This moment the filament between the extruder gear and the idler is not solid enough and the gear clicks creating a dent on the filament surface. 

The low  idler force against the extruder gear can also lead to clicking and dent generation.

The case is to print warping stuff like ABS, PC , ASA etc.  Do not close the case while printing PLA, PETG, PWB. 

RE: Keep getting a filament stuck message on my MK4S

@pink_clown,

• The issue never existed for me before the mk4 => mk4s upgrade.
• It is the actual filament stuck with clicking issue
• I print with PETG
• Opening the enclosure reduces but does not eliminate the issue.

I agree it is a preheating issue.  unfortunately the change that caused this came with the mk4s upgrade or related firmware updates.  It will need to be rolled back or fixed.  My guess is a change was made for the higher feed rates is the root cause.

RE:

Try a bit temperature fidling with temperature and compare the filament profiles of MK4 and MK4S, sometimes they do not match. Sometimes tihgting the extruder idler spring screws can help, so the force of the idler bearing against the extruder gear will be stronger.

The higher feed rate requiers higher nozzle temperature which can cause a filament preheating before the extruder entrance, it becomes softer and the problem is just there.

Posted by: @alias23b

@pink_clown,

• The issue never existed for me before the mk4 => mk4s upgrade.
• It is the actual filament stuck with clicking issue
• I print with PETG
• Opening the enclosure reduces but does not eliminate the issue.

I agree it is a preheating issue.  unfortunately the change that caused this came with the mk4s upgrade or related firmware updates.  It will need to be rolled back or fixed.  My guess is a change was made for the higher feed rates is the root cause.

RE: Keep getting a filament stuck message on my MK4S

Ditto!!

RE: Keep getting a filament stuck message on my MK4S

My apologies for not re-reading the previous 4 pages of posts... My question, below, may already be answered and I didn't bother to check.

Posted by: @alias23b

@pink_clown,

• The issue never existed for me before the mk4 => mk4s upgrade.
• It is the actual filament stuck with clicking issue
• I print with PETG
• Opening the enclosure reduces but does not eliminate the issue.

I agree it is a preheating issue.  unfortunately the change that caused this came with the mk4s upgrade or related firmware updates.  It will need to be rolled back or fixed.  My guess is a change was made for the higher feed rates is the root cause.

Are you sure that you are using the high-flow nozzle that came with your MK4S upgrade kit, and/or using the correct printer profile for high-flow or standard flow nozzle (depending on which you have actually installed on your printer)? If you are accidentally using a high-flow profile with a standard flow nozzle you may be slicing with too high of a max volumetric flow. Prusa does provide both high-flow and standard flow printer profiles for the MK4S (I have both enabled in the configuration wizard because I use both nozzle types).

RE: Keep getting a filament stuck message on my MK4S

Hi All, Joan's answer has cured my sticking filament problem, the filament had swelled in the ptfe tube due to my enclosure getting too hot. As I pulled it out of the tube I had to pull very hard to remove it, I cut it off and inserted fresh off the reel and it slid in very easily, so the filament had swollen. Now I try to keep the temperature no higher than 26 - 27 degrees and I have had no further issues of it sticking with pet or pla. Thanks again Joan.

RE: Keep getting a filament stuck message on my MK4S

Thanks @pink_clown, I already tried temp changes and the extruder idler spring screws both ways, that didn't help. The high flow nozzle was giving me such poor quality prints, I reverted to a low flow nozzel (tried 3 different nozzles with no difference), printer profile in Prusa Slicer is Low flow MK4s, and the setting on the printer is set to the low flow nozzle too. I did all of that a couple of months ago.

I haven't tried the settings compare. That is a new suggestion. There's a lot there, so I'll give that a go the next time I run something.

Posted by: @pink_clown

Try a bit temperature fidling with temperature and compare the filament profiles of MK4 and MK4S, sometimes they do not match. Sometimes tihgting the extruder idler spring screws can help, so the force of the idler bearing against the extruder gear will be stronger.

The higher feed rate requiers higher nozzle temperature which can cause a filament preheating before the extruder entrance, it becomes softer and the problem is just there.

Posted by: @alias23b

@pink_clown,

• The issue never existed for me before the mk4 => mk4s upgrade.
• It is the actual filament stuck with clicking issue
• I print with PETG
• Opening the enclosure reduces but does not eliminate the issue.

I agree it is a preheating issue.  unfortunately the change that caused this came with the mk4s upgrade or related firmware updates.  It will need to be rolled back or fixed.  My guess is a change was made for the higher feed rates is the root cause.

 

RE: Keep getting a filament stuck message on my MK4S

On the advice of Prusa Support I reverted to the low flow nozzle a couple of months ago (I've tried 3 different nozzles with no difference in result). The printer profile in Prusa Slicer is Low flow, and the setting on the printer is set to the low flow nozzle too.

Posted by: @sembazuru

My apologies for not re-reading the previous 4 pages of posts... My question, below, may already be answered and I didn't bother to check.

Posted by: @alias23b

@pink_clown,

• The issue never existed for me before the mk4 => mk4s upgrade.
• It is the actual filament stuck with clicking issue
• I print with PETG
• Opening the enclosure reduces but does not eliminate the issue.

I agree it is a preheating issue.  unfortunately the change that caused this came with the mk4s upgrade or related firmware updates.  It will need to be rolled back or fixed.  My guess is a change was made for the higher feed rates is the root cause.

Are you sure that you are using the high-flow nozzle that came with your MK4S upgrade kit, and/or using the correct printer profile for high-flow or standard flow nozzle (depending on which you have actually installed on your printer)? If you are accidentally using a high-flow profile with a standard flow nozzle you may be slicing with too high of a max volumetric flow. Prusa does provide both high-flow and standard flow printer profiles for the MK4S (I have both enabled in the configuration wizard because I use both nozzle types).

RE: Keep getting a filament stuck message on my MK4S

 @pink_clown, the filament profiles did have some differences.  I had originally saved the default MK4 settings off with different colors and was still using those filament profiles.    I reverted the filament profile to the current default for the MK4s and ran a test print with the doors closed.  It failed right away, twice.  I appreciate the new idea, unfortunately it appears to have made no difference for me

Posted by: @alias23b

Thanks @pink_clown, I already tried temp changes and the extruder idler spring screws both ways, that didn't help. The high flow nozzle was giving me such poor quality prints, I reverted to a low flow nozzel (tried 3 different nozzles with no difference), printer profile in Prusa Slicer is Low flow MK4s, and the setting on the printer is set to the low flow nozzle too. I did all of that a couple of months ago.

I haven't tried the settings compare. That is a new suggestion. There's a lot there, so I'll give that a go the next time I run something.

Posted by: @pink_clown

Try a bit temperature fidling with temperature and compare the filament profiles of MK4 and MK4S, sometimes they do not match. Sometimes tihgting the extruder idler spring screws can help, so the force of the idler bearing against the extruder gear will be stronger.

The higher feed rate requiers higher nozzle temperature which can cause a filament preheating before the extruder entrance, it becomes softer and the problem is just there.

Posted by: @alias23b

@pink_clown,

• The issue never existed for me before the mk4 => mk4s upgrade.
• It is the actual filament stuck with clicking issue
• I print with PETG
• Opening the enclosure reduces but does not eliminate the issue.

I agree it is a preheating issue.  unfortunately the change that caused this came with the mk4s upgrade or related firmware updates.  It will need to be rolled back or fixed.  My guess is a change was made for the higher feed rates is the root cause.

 

 

RE: Keep getting a filament stuck message on my MK4S

I had the "filament stuck" error constantly when printing a big PC Blend model but it was definitely due to warping. After I clamped the PEI sheet onto the bed and began again from scratch, the error never came back ...