Jam-like issue seems to not actually be a jam problem?
Hi!
I've been fighting a strange problem with my i3 MK3S for a while now and I'm not sure what to try next to resolve it. Basically, I'm experiencing what looks like a jam, but I've tried most if not all the usual "how to fix a jam" solutions and I'm still seeing it. I'll open with a couple of images. I've been hoping to get David Östman's The Dark Knight bust printed and, while arguably successful, there's a noticeable problem with both the top and bottom pieces of the bust.
Basically, somewhere in the last 30 minutes of the print... it seems to just stops extruding. I've seen the problem a few other times with some prints. A few skipped a couple layers and kept printing but wasn't attaching to the model so it missed the top and made some spaghetti instead, some jammed so bad it just stopped extruding altogether, and others had the problem far earlier in the print. The bottom of this model is my forth attempt, the first 3 failed fair earlier in the same way. Anyways, these two pieces are the best I've gotten out of my Prusa in a while.
Things I've tried so far:
- I ran some ESun cleaning filament thru. Quite a bit. I noticed it was feeding out of the nozzle at an angle so I did a couple cold pulls with it until it was feeding normally. I did notice a bit of particulate matter in the first cold pulls but it went away quick.
- I did notice early on that the extruder idler was clicking early on. With my MK3S upgrade I had to rebuild it because I missed a recessed nut, and on the rebuild I forgot that the tension screw needs to be a lot tighter. After tightening the clicking disappears, at least until it starts to jam. I did also reseat the idler's little arm to make sure it wasn't flexing around.
- I've tried different filaments. I first noticed the problem with Fillamentum, but I'm fairly sure that was due to the extruder idler not being tight enough. My Prusament rolls are having the same problem, as do Hatchbox and CC3D Silk.
- I rebuilt the E-Axis for a third time at some point to ensure the PTFE tube was seated properly in the extruder pathway. It's honestly quite hard for me to tell if it's right but I'm fairly confident I've got it as good as I can get it.
- When printing CC3D Silk I have to print at ~225C instead of 210C of normal PLA to get it to not retract back on itself too quickly. I had swapped back and forth a bit, and I was thinking maybe some was stuck in the extruder pathway and not melting enough to get pushed out with standard PLA. I ran thru another 4 or 5 cold pulls with the ESun filament, the last 2 coming out utterly flawless and perfectly shaped to the nozzle path, no particulates visible with the naked eye. I did this before the best success I had with the bottom of the above pictured bust, and I was monitoring it closely for the first 8 hours or so and noticed no clicking, under-extrusion, or other such problems. In other words, it would seem that if there is currently a jam, it was created during that print.
- I live in Las Vegas, and the heat has been picking up since I started noticing the problem. I was wondering if maybe my AC was causing some level of thermal "shock" to the extruder, as in just causing too much ambient fluctuation. I do have a genuine E3D heat sock on the heater block so I kind of doubt it, or at least it shouldn't be so drastic the printer can't handle it, but I went ahead and moved my printer around so it shouldn't be nearly as effected by the sudden rush of colder air in the room.
Things I haven't tried yet but I'm considering, and reasons why I'm holding off a bit:
- Changing the nozzle. Pretty early on with my Prusa I put a genuine E3D hardened steel nozzle on because I like using PLA's with flakes in them, namely glitter filled ones. Or, more accurately, I had a bunch to use and figured I should put a hardened steel nozzle on. The install didn't go super well (due to my failures, not the printers) but it proved to be more of a hassle than I want to deal with regularly. Anyways, the main reason I'm holding off on swapping the nozzle is I just don't think that the nozzle itself would cause such a problem so late in a print, or more importantly if it were a problem it would be a lot more noticeable and frequent than it is. Thoughts?
- Changing the heat-break. What Joel talks about in his video about jams with Proto-pasta filament doesn't feel like my exact problem, but it does feel super close to it. I'm considering swapping the heat-break to a standard E3D one mostly as an opportunity to see if it works. That said, messing around with the extruder in this way is definitely inside my "I can do it but I'm not super comfortable doing it" range, so my question to the community is simply how likely is this my issue? Worth trying?
- Oiling the filament. They mention it and try it in the above video, and I'm just not a fan of oiling filament. To me, it's not worth the risks for what should really be fixed mechanically. I imagine it might be worth giving a shot just to see if it works, like they say in the video something to experiment with. Thoughts?
- Other ideas? I'm open to hearing any thoughts. Like I said up top, I'm not really considering this a "true" jam, as whenever I do clean up the pathway and do cold pulls I'm not seeing anything I'd expect to see from a true jam, or if I do I feel like it occurred during the print that failed, not that the print itself caused anything that I'm finding that looks like a jam. I'm more so worried that I have something else going on that's effectively creating a jam-like situation or causing these "minor" jams very regularly.
RE: Jam-like issue seems to not actually be a jam problem?
One additional idea is to check the temperature of the extruder motor. If that motor gets too hot, it'll heat the extruder gear, too, and the gear will soften the PLA and will start slipping. This is one common cause of extrusion failing during long prints.
RE: Jam-like issue seems to not actually be a jam problem?
One additional idea is to check the temperature of the extruder motor. If that motor gets too hot, it'll heat the extruder gear, too, and the gear will soften the PLA and will start slipping. This is one common cause of extrusion failing during long prints.
That's a great idea. It makes sense and I think I've heard of it before but it didn't occur to me to check. I've got a cheap IR temp gun I use for work, I'll consider trying to gauge the temp at a few points in a long print to check on it.
That said, I did see the problem on occasion really quickly into a long print, so not even a couple hours. Maybe it's worth running through a thorough pathway cleaning then slapping a couple heatsinks on the extruder motor to see if it helps.
RE: Jam-like issue seems to not actually be a jam problem?
The next thing is to check that the set screws on the extruder gear are tight. Bondtech recommends blue Loctite to prevent loosening.
Another possibility is a wet filament. Rarely a problem with PLA, as it's not very hygroscopic, but when moisture evaporates in the extruder, the vapor expands, causes backpressure and will push the molten plastic back up the heatbreak, around the solid filament, increasing friction and causing a temporary jam.
And to get more clues, the behavior of the 'jam' should be observed. Does stopping a print, unloading and reloading filament fix it? Does pausing a print and waiting for 15 minutes fix it? Or do you need to do a cleaning cycle? Does it tend to clear up by itself?
RE: Jam-like issue seems to not actually be a jam problem?
Today's been busy, I'll try to find some time this week to look at the set screws.
I somewhat doubt it's wet filament. I store my filament well, in a bag with at least one silica gel packet, in the original box, in a drawer with all the other filament, and with like... half a pound or more of silica gel packets in the drawer. And I live in a desert, it's just dry here to begin with. I used to live in North Carolina where I did get wet filament and I'm used to hearing the telltale popping of moisturized filament, haven't heard a peep like it since moving out here.
As for the remainder: I can't speak to some of the earlier situations well, it's been a while since this started. I really only have free time on the weekends and most weekends I'd rather relax than deal with this. Recently though, each one has been a "fresh" jam. Unloading/reloading filament, pausing, etc. isn't enough, I have to do a cleaning cycle. I do recall some of the times I saw it earlier I'd go to make lunch or something and when I got back it had missed a few layers but picked back up, but enough that the print was scrubbed. So it sometimes would clear up by itself. For example, when the top of the pictured bust failed it missed about 4 layers, but by that point that's very little actual printing area, and when it started again it just made noodles. That's actually why I've been leaning away from calling it a straight up jam, I'm not used to such brief jams.
RE: Jam-like issue seems to not actually be a jam problem?
Today's been busy, I'll try to find some time this week to look at the set screws. I somewhat doubt it's wet filament.
I would be very surprised if it were any of these two. I wanted to add them for completeness.
And I live in a desert, it's just dry here to begin with.
That reminds me of one more potential issue: Heatsink/heatbreak temperatures. In case the ambient temperature is high, or the heatsink and fan are covered in dust or you're printing PLA in an enclosure, the heatsink may not be able to cool the heatbreak low enough to avoid melting plastic above the heatbreak zone. That leads to temporary clogs. This can also be caused by an improperly assembled hot-end where there isn't enough space between the heater block and the heatsink.
One more is a nozzle not tightened properly (while hot, with space left between nozzle and heater block, to 3Nm). Then plastic can flow into all kinds of places.
And back to the 'too hot motor' issue: That one is easily caused by overtightened springs on the extruder idler pulley. It may seem that the tighter, the better, and that's kinda true, only the motor has to work harder, making the pulleys hotter, and the PLA softer, eventually slipping despite the higher pressure.
As for the remainder: I can't speak to some of the earlier situations well, it's been a while since this started. I really only have free time on the weekends and most weekends I'd rather relax than deal with this. Recently though, each one has been a "fresh" jam. Unloading/reloading filament, pausing, etc. isn't enough, I have to do a cleaning cycle. I do recall some of the times I saw it earlier I'd go to make lunch or something and when I got back it had missed a few layers but picked back up, but enough that the print was scrubbed. So it sometimes would clear up by itself. For example, when the top of the pictured bust failed it missed about 4 layers, but by that point that's very little actual printing area, and when it started again it just made noodles. That's actually why I've been leaning away from calling it a straight up jam, I'm not used to such brief jams.
Unmeltable debris in the nozzle (like a tiny bit of PTFE) would be a cause matching that behavior. But you mentioned successful cold pulls, so unlikely. Next possible the too hot heatbreak I mention above, causing similar effect to what I described with wet filament. And too hot a motor would also match the description. Waiting may not help in the case of the hot motor if the filament is already ground away.
RE: Jam-like issue seems to not actually be a jam problem?
Sorry for the long delay. The weekend I wanted to dedicate to further testing I adopted a cat and didn't want to run the printers so she could adjust without that added noise-threat. This past weekend I sat down to start it up and thought I had a good idea of what was going on part of the way through.
On 5/27 I started printing with some CC3D Silk PLA, which I print ~230C. All was printing well for ~90 hours, almost non-stop. I figured the higher printing temperature was allowing the extruder to keep the flow rate up. I wanted to keep going with the CC3D to burn through some of the filament spool I had, so I just kept going. The morning of 6/3 (today) I started another print, this one about 12 hours, and somewhere around hour 8 I'm guessing it failed. It "finished" and created a big ol' jam in the process. Enough so that when trying to remove it the filament snapped inside the extruder body and my hand slipped up against the Z axis lead screw causing a pretty nice gash.
Anyways. I'm abandoning the project for the night. I'm going to deconstruct the extruder body to see if I can get the filament out and see about getting a replacement for the PTFE tube as at my cursory look it's pretty marred at this point and probably producing some flakes in the filament path.
RE: Jam-like issue seems to not actually be a jam problem?
Slice the model, then spend some time in preview mode looking at what's going on with the print at the layers the jams occur. In particular, look for retractions, and notably lots of retractions in a small area. Retractions run the extruder motor, lots of retractions run it harder, resulting in more heat. PLA gets soft at relatively low temps, and soft filament can result in jams.
Having survived Phoenix for 13 years, I know what you're talking about with temps. Keep in mind the E3D V6 hotend is air cooled, and rated to about 40C ambient temps, or what we called a mild day in the desert. Enclosures make it worse. If your ambient temps are a concern, look into cooling options. Last year at the peak of summer, some folks resorted to a fan to move air around the extruder. The new extruder design mitigates this a bit, but I expect another summertime spike in "heat creep" posts.
One simple test is to simply slow down at the affected layers and see if that helps. Also, take a look at Printer Settings->Extruder 1->Retraction->Minimum travel after retraction. That's the minimum move required to trigger a retraction. If you have a lot of retractions occurring close together, try using a larger value here.
Perhaps you could slice off the ears and just print those for a more manageable test print. Of course, the problem may only manifest at long run times, but it's worth seeing if you can re-create it on demand. I've seen these problems with ears and fingers on busts, so look for those bits to test with.
Before you tear anything apart, open the extruder tension screws on the left and lift the door on the right and inspect carefully. Do you have filament jammed below the gear but above the hotend? If you can't fish it out with tweezers, try this:
- Raise Z to max.
- Set nozzle temp to 285C.
- Use a rod of 6in/15cm X 1.5mm, polish the ends (to avoid PTFE tube damage) and insert it down through the filament feed, past the bondtech gears, into the PTFE tube.
With a bit of luck, you will be able to push the stuck filament down into the hotend where it can be extruded. In extreme cases, remove the nozzle. Be sure to brace the extruder throughout to avoid twisting, and apply gentle downward pressure. You can also poke up from below if needed. Hopefully this will avoid the need for a teardown.
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RE: Jam-like issue seems to not actually be a jam problem?
Just posting a followup in case others stumble on this and are looking for a solution:
So, while I agree with bobstro that a full tear down shouldn't have been necessary, it turned out it would have helped a lot if I didn't end up going to a more extreme solution anyways. A bit of background: My company does yearly end of fiscal bonuses which we get in the summer, and when I found out how much mine was I thought, "... WELL. Guess I'm just buying a new hotend assembly." Mostly because I figured I'd rather get a from factory assembly to compare to so I could figure out what was wrong, and also so I could somewhat wash my hands of any mistakes I made with my previous assembly.
Once I got it and started installing I noticed a couple problems: One, that most recent jam was severe. I wouldn't have been able to get the filament out without getting the previously installed hotend assembly off the X-Axis. Two, upon full removal I compared the PTFE tube from my old assembly to the new and the old one had another millimeter or so of height sticking out of the actual assembly. So my fear that the PTFE tube was not inserted properly was almost certainly correct, and the top end of the PTFE tube is in far worse condition than I originally thought so it's nearly impossible some of the bits torn off weren't in the pathway. So yeah, PTFE shreds were probably causing the jams. Definitely user error, but I also distinctly recall when inserting it both times (I went thru two while diagnosing the problem) I thought to myself, "I'm pretty damn sure I'm doing this wrong but I don't know how else to do it given what documentation we do have."
I did run into a separate problem during the install of the new assembly: The thermistor lead that plugs into the control board tore apart really easily when I tried to remove it to rerun the wires. The wires pulled out of the plug end with minor effort and the plastic of the plug just crumbled as I tried to remove it. Luckily I was able to remove the thermistor from the original assembly and use that instead.
When I ordered the new hotend assembly I also ordered a powder coated sheet, so I redid the setup wizard (considering all new assembly it's worth doing anyways), got everything leveled again, and I've done a couple prints. I'm still thinking there's a decent chance the extruder motor is heating up too much but I've dropped the AC temp a couple degrees, got a new workbench that's taller (should help keep the airflow around the printer better), and I'm keeping an eye on it when I can with my IR thermal gun. It's been hovering around 48C once its ~1 hour in and past that which I'm comfortable with.
What I've learned from this:
- Installing the PTFE tube in the hotend assembly properly is more difficult than I'd like it be. Maybe mine was just finicky because of some other problem but I'm looking at this whole experience thinking, "it must be able to do this better."
- The powdered coated sheet is a lot nicer. Things are planted amazing when at temp, and self release flawlessly once cooled down. The texture is nice, too.
- I'm not thrilled with it considering the AC bill in the desert is obscene but I'm going to continue leaving it a good bit cooler to see if it'll help.
- I'm not suggesting anyone else go quite so far as buying a whole new assembly to work around a jam problem. I did because I have the means but not the patience to address it otherwise. If I had the time to really work through the problem I could have figured this out ages ago and simply gotten a new PTFE tube or even made one instead of the expense of a while new assembly.
Things I'm still concerned about:
- The temp of the extruder motor still feels like a potential problem for me. I'm hoping that the real reason my printer was jamming was the PTFE tube being shredded and if anything the motor was a tiny bit too hot which just exacerbated the problem. Now that the pathway should be clean it hopefully won't cause issues if it is a tiny bit too hot.
- I've started to think that the CC3D Silk filament I've been using for a while might be exacerbating the problem as well. While printing I hear a squeak from the extruder when doing retractions. I'm wondering if something about the material is gripping the PTFE tube and pulling it back up the extruder assembly during retractions? It hadn't occurred to me until recently that it could be part of the issue. I do know when loading the filament it doesn't come out of the nozzle in a single well formed string, but appears to "pull back up on itself" is the best I can describe it. A bit comes out and what comes out after forms around it. It's as if in it's molten state it wants to congeal with itself and make globules. I've printed it at closer to PETG temps to work around that problem. Anyways, the concern is that if it's doing that inside the filament pathway it might be gripping the PTFE tube and yanking it back up during retractions. I'm currently printing some now and when this print is done I'm going to take a peak at the tube again to see if it's noticeably higher/closer to the Bondtech gears than it had been during re-assembly.
- I recently adopted a cat. I've gotten one of these to encourage her to not get too close to the printer but she still pokes around it sometimes (not sure if I can recommend this thing, it detects me flawless but she barely sets it off). She sheds quite a lot and I'm also worried her hair might be gunking things up. I've been wanting to build an enclosure for the printer to stop that but with the heat concerns I'm just not sure.
Anyways, I wanted to follow up on this thread for anyone that stumbled on it and wants to see how it ended up for their own education. I'm still not 100% confident in the printer yet but considering what I found during re-assembly I'm pretty sure I've found the major problem and now it's just a matter of finding out if there are actually minor problems that will cause continued jams.
RE: Jam-like issue seems to not actually be a jam problem?
...
Things I'm still concerned about:
- ...
- I've started to think that the CC3D Silk filament I've been using for a while might be exacerbating the problem as well. While printing I hear a squeak from the extruder when doing retractions. I'm wondering if something about the material is gripping the PTFE tube and pulling it back up the extruder assembly during retractions? It hadn't occurred to me until recently that it could be part of the issue. I do know when loading the filament it doesn't come out of the nozzle in a single well formed string, but appears to "pull back up on itself" is the best I can describe it. A bit comes out and what comes out after forms around it. It's as if in it's molten state it wants to congeal with itself and make globules. I've printed it at closer to PETG temps to work around that problem. Anyways, the concern is that if it's doing that inside the filament pathway it might be gripping the PTFE tube and yanking it back up during retractions. I'm currently printing some now and when this print is done I'm going to take a peak at the tube again to see if it's noticeably higher/closer to the Bondtech gears than it had been during re-assembly.
- ...
A quicker followup in order not besmirch the good name of CC3D: After 2 identical back to back 12 hour prints with a decent bit of retraction I took a peak and the PTFE tube appears to be exactly where I left it. The squeaking is just squeaking I guess.
That said, the second print had some bad lift off the bed with the CC3D Silk PLA, which is weird because after starting the second I noticed some slight elephant footing on the first and thought I'd raise my Live Adjust Z.... I'm hoping the little automatic air spray can thing I have was aimed to closely to the bed and went off a few times, spraying cold air across the bed causing the lift. Going to experiment with that thought by relocating it.
RE: Jam-like issue seems to not actually be a jam problem?
And it's jamming again on returning to bog standard PLA. I picked up a couple of rolls of Anycubic PLA off Amazon on a sale price and it jammed just a few hours into a print.
Cleared the jam, no debris in the cleaning filament as it passed thru normally or on the cold pulls (perfect nozzle shape on the tip, the edges were higher up were marred by the extruder gear), pathway/PTFE tube looking clean, loosened the idler screw a bit to avoid any over exertion on the extruder motor, ran it again just to see what would happen, heard the telltale clicking not even 2 hours into the print and sure enough it jammed again.
The extruder motor was warmer than the build plate on touch. So I'm pretty sure I'm looking at needing to cool it, or possibly the Anycubic PLA being a problem. I'm going to try again with Prusament tomorrow (too late to monitor it for the first few hours tonight), and if still a problem I'll investigate cooling the extruder motor I guess.
I'll admit, I'm really burned out on this. I think it's ridiculous my FLSun QQ-S, a less than $400 printer made with Chinese clone parts, is proving more reliable. Between my heated bed having a dip in it just off center, which customer support told me to just use the edge adjustments in firmware to work around, and now this after performing the MK3S upgrade... It's just a hassle. This printer is supposed to be the best, supposed to be a workhorse. Mine certainly isn't. Sure, the FLSun has it's own problems, but it's all just Cura slicing problems. I keep asking myself, "At what point should I just chuck this thing on Craigslist and be done with it?" I hate to sound so defeated, but it's just so frustrating.
RE: Jam-like issue seems to not actually be a jam problem?
Generally jams are quite simple problems to solve. But no photos of the problems makes it rather difficult to diagnose. The two initial images show prints that stopped early. And that could be for just about any reason. Jam, crash, power fail, etc.
Post photos of the bad PTFE; of the extruder gear area, of a cold pull, or a unload after a jam.
RE: Jam-like issue seems to not actually be a jam problem?
Do you have any more examples of failed prints?
From what it sounds like, your extruder motor gets too hot, the heat creeps to the extruder gear and causes the PLA filament to melt enough such that the gears cannot grip it properly anymore. I had the same problem and it took me a while to figure out that I wasn't dealing with conventional jamming.
My solution was to print and install this extruder cooler with a 2nd Noctua fan. The problem hasn't occured ever since even when printing inside an enclosure. It's not abnormal for these NEMA motors to become hot, but I have read a case of somebody here who got a replacement from Prusa because they suspected the motor being bad. It might be worth a shot if you can determine that this is indeed the problem.
Some troubleshooting questions:
- Does this only occur with PLA? This is important because materials like ABS and PETG have high enough glass transition temperatures to resist this.
- What resolution are you printing at? This would usually happen to me at lower resolutions (0.1 mm and finer) since the filament flow is slower and the filament thusly remains near the hot extruder gear longer.
- After a print fails and you unload the filament, can you observe it being worn away only from one side? This would point to the extruder gear melting theory. With a typical jam, the filament would be worn away from both sides as both gears grind away at it trying to move it down the nozzle.
And addressing some other concerns you raised:
- Don't mind squeaky filament. There is something with the additives for these silk filaments that make them squeak - the same happens with my silk PLA from Eryone for example.
- If you are concerned about the temperature from an enclosure but want to keep cat hair out, I would suggest looking at the official Lack enclosure parts and build that but without the Plexi walls. Instead, just install insect nets for windows between the legs of the table.
- Also protect your filament. Some filaments seem to attract cat hair like a magnet (speaking from experience as a fellow cat-owner).
RE: Jam-like issue seems to not actually be a jam problem?
Do you have any more examples of failed prints?
From what it sounds like, your extruder motor gets too hot, the heat creeps to the extruder gear and causes the PLA filament to melt enough such that the gears cannot grip it properly anymore. I had the same problem and it took me a while to figure out that I wasn't dealing with conventional jamming.
My solution was to print and install this extruder cooler with a 2nd Noctua fan. The problem hasn't occured ever since even when printing inside an enclosure. It's not abnormal for these NEMA motors to become hot, but I have read a case of somebody here who got a replacement from Prusa because they suspected the motor being bad. It might be worth a shot if you can determine that this is indeed the problem.
Some troubleshooting questions:
- Does this only occur with PLA? This is important because materials like ABS and PETG have high enough glass transition temperatures to resist this.
- What resolution are you printing at? This would usually happen to me at lower resolutions (0.1 mm and finer) since the filament flow is slower and the filament thusly remains near the hot extruder gear longer.
- After a print fails and you unload the filament, can you observe it being worn away only from one side? This would point to the extruder gear melting theory. With a typical jam, the filament would be worn away from both sides as both gears grind away at it trying to move it down the nozzle.
And addressing some other concerns you raised:
- Don't mind squeaky filament. There is something with the additives for these silk filaments that make them squeak - the same happens with my silk PLA from Eryone for example.
- If you are concerned about the temperature from an enclosure but want to keep cat hair out, I would suggest looking at the official Lack enclosure parts and build that but without the Plexi walls. Instead, just install insect nets for windows between the legs of the table.
- Also protect your filament. Some filaments seem to attract cat hair like a magnet (speaking from experience as a fellow cat-owner).
The cooler you linked is very similar to the one I was considering from CG-Tech, but I hadn't dug around further to find one more suited for the MK3S. Thanks for that!
To somewhat test the theory I picked up a desk fan that I'm going to try to angle in a way to get more air around/over the extruder motor while avoiding the bed, just to see if I can see some difference. As for your bullet lists:
- I only really print in PLA. The issue happens far less with the Silk PLA from CC3D, which I usually print around PET-G temps, hence why I'm leaning more and more towards heat creep being the culprit. This weekend I'm going to try printing some PET-G as a test.
- I print from .2 to .1 usually. I do see the issue more readily at .1 resolutions.
- Filament was usually more worn on the directly driven side. It was worn on both, but more noticeable on the extruder motor side.
- As for the squeak, glad to hear that.
- Insect nets are a very interesting idea. I was going to look at the Plexi walls and adding a minor modification of an ambient (in the box) temperature sensor and external fan but the nets sound a boat load easier.
- I picked up some of these off Amazon to help clean off the filament before entering the extruder, but with it sitting loose on the filament line it gets pulled to the extruder then the pull on the filament draws the foam down with a lot of force and it was nearly tearing it through the plastic shell. I'm focused on addressing this jamming issue for now, relying on my "put the filament back in the bag, that back in the box, and the box in a storage drawer when not in use" method until then, then I'll look at a filament guide that I clip these filters in.
RE: Jam-like issue seems to not actually be a jam problem?
Fan worked as intended but did not stop the jam. I heard the clicking, let the print keep going for a moment to get the temps on the motor, it was around 42C, down from low 50C's at the same point on previous attempts.
A couple shots of the extruder gears right after the jam:
I was hoping to get a picture of the filament I was using after unloading but to get it out I had to get the temp up, extrude a bit more to get it to unclog itself, and then the unload was successful. That means the marring on the filament ended up thru the nozzle, so not point in a picture as there's nothing to show. I had tried to manually pull it at temp (with the idler loose as pictured above) but was lifting the printer. I didn't want to risk snapping the filament and having to do more work to unjam it, or worse breaking something.
Cold pulls went as they usually do. First was mostly clean but pulled apart, second was damn near flawless. The first picture appears to have some dark spots but it's really difficult to get an angle/lighting to show that it's just a density thing. On close inspection it is clean for what I can see.
So, while the extruder motor did get to a much lower temp, it is now looking to be a different issue. It'd probably be worth doing a fan mod (I've also considered swapping the extruder motor to an LDO from Printed Solid that I'm seeing reddit folk report runs much cooler) to avoid further issues but I'm fairly sure I'm looking at a different issue I'm not sure where to turn now...
RE: Jam-like issue seems to not actually be a jam problem?
You'd do well to replace the heat break with the stock E3D version. You are having the dreaded heat break jam caused by the step down in the melt transition zone. See the rings of filament that have sheared as the extruder tires to push the filament? Only one way that can happen.
RE: Jam-like issue seems to not actually be a jam problem?
I have a major Prusament filament clog tonight. I followed the knowledge base advice but could not pull out the filament. I removed the nozzle, still no joy. I ended up dismantling the hotend assembly. So I took the opportunity to fit a genuine E3DV6 stock heatbreak and fitted a silicone sock also. All working great so far.
Nigel
Life is keeping interested and excited by knowledge and new things.
RE: Jam-like issue seems to not actually be a jam problem?
...yeaaaahhh.... I saw that 3D Printing Nerd video when Joel posted it, thought it sounded like a possible problem for me, and was really hoping that wasn't it.
I can do the heatbreak replacement but was hoping not to have to. I've proven a few times to myself that my patience is quite strong enough to stay as delicate as I need to be. I'm probably going to put in an order for the heatbreak as well as the LDO motor's from Printed Solid just to take care of much as I can at once.
God I hope that's it... I don't know how much more time/money I'm willing to sink into this machine just to make it work consistently.
RE: Jam-like issue seems to not actually be a jam problem?
It might not be the heat break step causing the jam; but I can't think of any other way to explain the rings on the filament you pulled out and they are the right place in the column. Most of the jams I've experienced and seen with others, the filament unloads with significant 2.2 mm diameter stubs, like these. If you've ever seen this on your filament, you can be confident the heat break is the issue.
RE: Jam-like issue seems to not actually be a jam problem?
OK.... hopefully this is the final "in case anyone stumbles on this and is looking for a final answer" update, and the fact that I'm saying even that much likely means my printer is currently in the process of jamming itself unbeknownst to me, but..
Just a couple hours to go for a ~46 hour complex print to complete after all the fixes are applied, and beyond some serious stringing it looks like the standard heatbreak is the fix, although I've made a couple other changes to hopefully drastically reduce the chances of this cropping up again meaning it's plausible something besides the heatbreak was my real fix. Perseverance is nice, throwing money at replacement parts is easier, though.
In the process of swapping the heatbreak I melted the PTFE tube's collet in the heatsink, so I had to wait for a couple of those (and matching clips to avoid future PTFE tube shifting problems) to come in. I could have printed some on my FLSun QQ-S but didn't want to risk in the future thinking, "Well, it's still a problem, is it the printed collet that's bad?" and have to order one anyways.
If you're facing similar troubles and are curious about the full extent of solutions that appear to have solved my problem:
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Installed standard E3D heatbreak
- The fact I'm adding a voice to choir of "Change to the E3D standard heatbreak" is a bit annoying to me. As in, there's clearly a problem. Personally I'd be interested to hear from Prusa Research as to why they think this is happening.
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Swapped the extruder motor to this: LDO NEMA 17 MOTOR COOLER LDO-42STH40-1004ASR
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With the standard motor I was seeing it pushing 50C on relatively basic gcode, hover around 55C for something vaguely complex, and push if not break 60C before jamming during complex stuff. With this "Cooler" motor I haven't seen it break 45C during this print, usually hovering between 39-41C. I made 0 changes to my slicing profile or firmware (beyond running the setup wizard again since I had to do a full deconstruct of the extruder axis), and the only thing I'm noticing is very fine stringing, which is easily worked around.
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Instead of the Sunon fans, I'm trying these: FYSETC fans on Amazon
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I was going to hold off on this, but when I needed to order new collets I debated it, decided against getting the Sunon's just because I thought, "the Noctua should honestly be good enough," so I skipped it when placing the order for other parts. Then I realized it'd be dumb not to install a better fan while doing everything else, wanted to get something quick enough that I could do it all at once without further delays once the main things were in, and went with these. They definitely are blowing more air than the Noctua, and are barely any louder. The sleeve is bulkier than the Noctua and that made it more difficult to route the cables, but it works. Longevity is going to be the question now.
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