Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models  

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

I paid € 800 for this?!

I feel the exact same thing. I shouldn't have to put thermal paste on something like this. Between this and jumping through all the crap I did to get here. I am thinking about getting a refund.

But I'm thinking it's also the motor, but I'm not a 100% sure.

This is what is happening with my prints. https://photos.app.goo.gl/5Pyj1aoj8V2sRgW89

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

After two months of no issues, unfortunately I started to have the exact "clicking issue". Has anyone tried the new extruder ?

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] This is what is happening with my prints. https://photos.app.goo.gl/5Pyj1aoj8V2sRgW89
Do your problems with that print always start at the fingers? Those are small perimeters, and it's likely the printer is doing a lot of retractions in rapid succession, which runs the extruder motor heavily. This results in heat. Depending on where you live, your ambient temps may be considerably warmer than normal this time of year, and you might be hitting the tipping point.

Try testing the motor temp at a lower point in the print, then comparing it to the temp as you hit the fingers. Is it noticeably warmer?

As an experiment, you can try disabling retraction. You'll get a lot more stringing, but it will help isolate this problem. In Slic3r, you can find the setting under Printer Settings->Extruder 1->Retraction->Length. Setting that to 0 will disable retraction.

If that helps, you might be able to find a middle ground by disabling retraction if the extruder isn't moving much (e.g. on fingers). You can find this setting under Printer Settings->Extruder 1->Retraction->Minimum travel after retraction. Try setting this to something like 5 so it only retracts between shapes (fingers).

One of the slicers has a "reduce rapid retractions" to detect and adjust for this scenario, but I can't recall which at the moment.

Other considerations you may have already tried:

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] I have had to disassemble the hotend 4 times, because the filament was blocked.
Can you elaborate on this? Many such clogs can be cleared without tearing down the hotend.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] I have had to disassemble the hotend 4 times, because the filament was blocked.
Can you elaborate on this? Many such clogs can be cleared without tearing down the hotend.

For me, when trying to clear these clogs on a print that I've not been present for the clicking, the extruder gears have eaten through the filament to the point it will immediately snap when I pull on it leaving about 4mm of filament hanging out of the top of the PTFE tube. Sometimes I can grab this little nub with a pair of pliers and work it back out but often the filament will snap off again lower the the PTFE tube making it impossible to clear the plug without a complete extruder tear down which takes hours.

That's exactly what happened this morning and now I'm in for yet another tear down. I love this printer when it works... but I spend more time taking apart this extruder assembly than I do using it. I was hoping for something more reliable and easier to use than my Tevo Tarantula but now I think of my Tevo as the reliable printer that's easy to work on if there is an issue. This Mk3 is like a fancy sports car that does great things IF it decides to run but spends most of it's time in the shop.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] That's exactly what happened this morning and now I'm in for yet another tear down. I love this printer when it works... but I spend more time taking apart this extruder assembly than I do using it.
Try this instead of a full teardown:

If filament breaks off below the feeder gears (where the gears can push it into the hotend) but above the hotend (where it would melt), you can remove it fairly easily. To check for a blockage:

If the broken-off filament is still above the hotend and intact:

Alternately, if the blockage consists of melted material, or you're worried about pushing melted materials up into the PTFE tube and mechanism, you can insert the rod from above and push it down through the loosened extruder gears into the PTFE tube:

If using a length of wire, be sure to round off and polish the ends before inserting to avoid tearing up the PTFE tube.

See my previous response for other things you might check. Good luck with it!

Reverse the process to reassemble, remember this thing is still HOT.

What firmware are you running? Recent firmware updates addressed extruder motor overheating which could weaken filament above the hotend.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] This is what is happening with my prints. https://photos.app.goo.gl/5Pyj1aoj8V2sRgW89
Do your problems with that print always start at the fingers? Those are small perimeters, and it's likely the printer is doing a lot of retractions in rapid succession, which runs the extruder motor heavily. This results in heat. Depending on where you live, your ambient temps may be considerably warmer than normal this time of year, and you might be hitting the tipping point.

Try testing the motor temp at a lower point in the print, then comparing it to the temp as you hit the fingers. Is it noticeably warmer?

As an experiment, you can try disabling retraction. You'll get a lot more stringing, but it will help isolate this problem. In Slic3r, you can find the setting under Printer Settings->Extruder 1->Retraction->Length. Setting that to 0 will disable retraction.

If that helps, you might be able to find a middle ground by disabling retraction if the extruder isn't moving much (e.g. on fingers). You can find this setting under Printer Settings->Extruder 1->Retraction->Minimum travel after retraction. Try setting this to something like 5 so it only retracts between shapes (fingers).

One of the slicers has a "reduce rapid retractions" to detect and adjust for this scenario, but I can't recall which at the moment.

Other considerations you may have already tried:

I'm seeing this issue:
- with Prusa FW Version 3.3.1
- default retraction settings (0.2mm),
- no enclosure
- no additional fan customization
- after checking the gear alignment multiple times
- the default MK3 prusa-provided Cura profile which (I hope) correctly defines the flow rate and retractions settings

I have not :
- used the newly released extruder parts which are said to increase cooling - they are printing now on my functional (non-MK3) printer and I'll tear down my extruder again to clear my latest blockage when they are complete.
- tried thermal compound between the throat and the heat sink, I will add that when I change the extruder parts.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...]
- the default MK3 prusa-provided Cura profile which (I hope) correctly defines the flow rate and retractions settings
The Prusa profile for Cura is correct for typical prints, but the problem may be simply too many retractions in too short a period of time with your specific print under your current specific printing conditions. I'd try disabling retraction as a test. If the print succeeds (with stringing likely) then you know you can tune retraction settings. In Cura, I'd try adjusting:

These may provide a software work-around, at least until you get to try the hardware solutions.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] That's exactly what happened this morning and now I'm in for yet another tear down. I love this printer when it works... but I spend more time taking apart this extruder assembly than I do using it.
Try this instead of a full teardown:

If filament breaks off below the feeder gears (where the gears can push it into the hotend) but above the hotend (where it would melt), you can remove it fairly easily. To check for a blockage:

If the broken-off filament is still above the hotend and intact:

Alternately, if the blockage consists of melted material, or you're worried about pushing melted materials up into the PTFE tube and mechanism, you can insert the rod from above and push it down through the loosened extruder gears into the PTFE tube:

If using a length of wire, be sure to round off and polish the ends before inserting to avoid tearing up the PTFE tube.

See my previous response for other things you might check. Good luck with it!

Reverse the process to reassemble, remember this thing is still HOT.

What firmware are you running? Recent firmware updates addressed extruder motor overheating which could weaken filament above the hotend.

I VERY much appreciate the feedback because this issue is basically making this printer worthless for me, I'm becoming reluctant to use it because it clogs almost every print and then about 30% of the clogs break in the ptfe tube forcing me into increasingly painful maintenance.

I'm on 3.3.1 (I update it every time I tear down the extruder since I have to dial everything back in anyway and I just had to tear it down last week). I have tried the wire method with limited success but often what has happened is that I've pulled a particularly generously sized clog part way up into the PTFE area and jammed it in tightly before my second filament break inside the tube where I can no longer get to it. I have tried feeding a steel rod down into the PTFE and both pushing it by hand and gently taping it with a small hammer but once it's lodged in there that tightly it won't budge. I suppose I could hammer it though with enough force but I doubt my printer would last very long with me wailing on it with a hammer like that (though the thought has crossed my mind mid-tear down several times - I've had to take this thing apart 5-6 times this summer and am tired of it).

What actually might help would be the ability in FW to shut off the heat sink fan. This is the trick I play on my other printer if clogs occur, I block the heat sink fan exit and allow the heat sink to warm up and soften the clog. I guess I could crack open the electronics case and unplug the fan but I hate to go messing around in there then things are live for fear of shorting something.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] This is the trick I play on my other printer if clogs occur, I block the heat sink fan exit and allow the heat sink to warm up and soften the clog. I guess I could crack open the electronics case and unplug the fan but I hate to go messing around in there then things are live for fear of shorting something.
Good idea. Maybe just put something over it? There are slip-on cooling fan covers on Thingiverse. A piece of paper inserted over the input might work. Not ideal from a performance perspective perhaps, but if it avoids lengthy tear-downs, worth a shot. If done with the wire inserted from above, you could leave the cooling fan input blocked as you apply steady pressure on the wire rod and hopefully pop the clog out.

I wonder if holding the wire from below with pliers and the heatblock heated up to PTFE-safe temp would transfer enough of the heat up the wire to be helpful in loosening a clog? Press the pliers against the block to facilitate heat transfer to the wire. I have been fortunate enough not to have such a nasty clog so far (knock on wood), but will keep it in mind.

You've got my sympathy. Good luck with it.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] This is the trick I play on my other printer if clogs occur, I block the heat sink fan exit and allow the heat sink to warm up and soften the clog. I guess I could crack open the electronics case and unplug the fan but I hate to go messing around in there then things are live for fear of shorting something.

...
I wonder if holding the wire from below with pliers and the heatblock heated up to PTFE-safe temp would transfer enough of the heat up the wire to be helpful in loosening a clog? Press the pliers against the block to facilitate heat transfer to the wire. I have been fortunate enough not to have such a nasty clog so far (knock on wood), but will keep it in mind.

You've got my sympathy. Good luck with it.

I was able to force the clog upwards by removing the nozzel and pushing up from the bottom. Good thought there!

As best I can tell, after initially pulling up and breaking the filament part way up the PTFE, pushing back down from the top was easy until the clog encountered the metal throat and then it wouldn't budge. Pushing up from the bottom with the nozzel removed and the hot end cooled was fairly easy and I was able to push enough filament back out the top to get a grip with pliers and pull it the rest of the way out. So this may save me some tear downs.

Does nothing for the real problem unfortunately. 🙁

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] I was able to force the clog upwards by removing the nozzel and pushing up from the bottom. Good thought there!
Glad it's worked for you. Tearing apart the extruder is definitely not a fun activity.

As to the root problem, could rapid retractions be a contributing factor? I haven't had the jamming problem yet, but I have had prints where I've selected slicer settings that made the extruder chug like a sewing machine and it got pretty warm.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] I have had to disassemble the hotend 4 times, because the filament was blocked.
Can you elaborate on this? Many such clogs can be cleared without tearing down the hotend.

Hi,

I had to disassemble the hotend, because even heating the nozzle to 285, I could not unclog, and the extruder could not push the filament.

Meanwhile the teflon tube came in to replace, i change for a 0.6 nozzle, and adjusted the extruder idler screws as explained in the last Prusa video, and the clicking disappeared.

After that I had problems getting first layer with petg, but I did, now my problem is my bed because my bed is not completely flat, I wanted to print many pieces at the same time, and it is not possible, I can only use some parts of the bed.

Update:

I did the test of the square, I started the test with live Z at -750, and from the middle I had to go down to -900, as you can see on the sheet, on the left side the bed is very low, a big depression.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

I still run into this constantly

What prusa video are you referring to for the idler screws?

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

[...] I was able to force the clog upwards by removing the nozzel and pushing up from the bottom. Good thought there!
Glad it's worked for you. Tearing apart the extruder is definitely not a fun activity.

As to the root problem, could rapid retractions be a contributing factor? I haven't had the jamming problem yet, but I have had prints where I've selected slicer settings that made the extruder chug like a sewing machine and it got pretty warm.

More retractions definitely make this issue worse (i.e. happen more frequently in a print) but I see it even on prints that don't have a bunch of retractions.

I still haven't had time to try the new parts which are supposed to increase cooling. Maybe I'll get to it this weekend.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

I found the idler screw video and I was indeed doing the tension of the idler screws into the extruder door incorrectly. Unfortunately following the new procedure doesn't impact the plugging / clicking issue for me.

I tore down my extruder (for the thousandth time) and:
1) replaced all of the parts with the R3 versions since they were advertised to enhance cooling.
2) applied thermal grease between the heat break and the heat sink (this was recommended earlier in the thread)

Unfortunately neither of these impacted the plugging / clicking issue for me - still happening.

Re: Clicking Extruder, followed by a jam across different temperatures, filaments, and .stl models

I believe this is the same topic in a different thread:

https://shop.prusa3d.com/forum/general-discussion-announcements-and-releases-f61/mk3-extruder-randomly-skipping-t23030-s40.html