Jammed and I don't know why
So I've been printing pretty much non-stop for the last month on 0.05mm prints.
About half way in I ran into faults with my filament sensor (plain MK3 (Dec)). It was with a lighter filament that I hadn't used before, so I turned it off and went on. I turned it back on with filaments that I've never had an issue with (including Prusa silver that came with the printer). It continued to have some issues so I'd turn it off when it fritzed and back on for the next print. Overall it continued to print fine otherwise though.
On my last print I found it stopped with 12 of 30 hours left (which means minutes after I checked it before bed 🙄 ). It acted like the filament sensor on the fritz again. It accepted me ejecting the filament and reinserting it, but when it started printing again it was clear that it had actually jammed and not extruded for some number of layers.
I killed the print and restarted it and all seemed fine for about 6 hours. At that point I started to hear the intermittent sound of slipping filament drive gears. The sensor was on and I couldn't actually tell if it was or wasn't extruding so I left it going. Lightly holding the filament I could still feel some movement, but I didn't think it felt quite right. After another few hours I was pretty sure it wasn't laying anything down any more so I stopped it.
This time when I tried to eject the filament it got stuck and I had to grab it with pliers and pull it out (this has only happened once before). When I tried to reinsert the filament I couldn't get the auto load to trip (been happening more and more lately), but after feeling like it got passed the gears it just stopped and wouldn't go further.
I have done no maintenance on the printer yet beyond periodically wiping off the X axis rods (maybe 1000 to 1200 hours on it) so I figured the gears (and clearly the filament sensor) needed to be cleaned and adjusted. Also I'm pretty sure the belts need some adjustment (reading high 290 values).
Tonight I opened it up and there wasn't much dust and no debris and the gears looked lined up well. The screws holding the door closed may have been a tad lose, but nothing major. I put it back together, heated it up, and it again failed to auto load and stopped short when I tried to push it through manually.
I removed the nozzle and found it packed full of hardened Prusa silver PLA (from the print that failed) with no sign of the Amazon blue PLA I was trying to push through. The nozzle was removed hot.
I then tried to load the filament again, but it again stopped short (no nozzle installed). I measured 56.8mm from the filament just into the PTFE tube to the point where it would no longer advance.
Anyone have any idea what is stuck/blocked and how I go about fixing it?
Re: Jammed and I don't know why
Just took a closer look at the nozzle to see what it would take to clean it and found two items of note.
The first is that there are signs of the filament coming out the threads, but only down low near the head? What was into the extruder was clear.
The second is that while the rear looked like a nice solid plug (as shown in pic), it was only a layer on top. My dental pick went right through when I poked at it.
Re: Jammed and I don't know why
Morning update:
Took my heat gun to the nozzle and got it cleaned up and reopened.
Fiddled with the extruder some more, but still no luck getting filament through. Figured "what the hell" and ran the temp up to 270. A few seconds after it got to temp I tried feeding PLA through it again. I still met resistance, but then a plug of the Prusa silver popped out the the bottom and the fresh PLA began to flow. Pulled it out, reset the temp to normal (215), reinstalled the nozzle, and was then able to run through 100mm using the extruder advancement in settings.
Ran a quick 5 minute print (0.2mm) with no issues and it's now running a 4 hour (0.2mm as well) print. If that goes through I'll cross my fingers and get back to my 0.05 prints.
Re: Jammed and I don't know why
As I expected, I cleared the jam, but the root cause still remains.
I spent the weekend printing various things (a couple small things at 0.05mm and a handful at 0.2mm) with probably about 20 hours of print time since clearing the jam.
All seeming well I loaded my the Prusa Silver again and kicked off my 37ish hour 0.05mm print. It completed this morning just fine. I started the next (and last!) 34 hour 0.05mm print and about an hour in I started hearing the sounds of grinding drive gears 🙁
I killed the job, ran through some scrap PLA at 280 degrees (with the nozzle installed this time) to clear things out again, and am now running 40 minute 0.2mm print to help clear things out.
Any ideas why I am suddenly getting these jams after a month printing with the exact same settings? What else can I do to clean it up so this stops happening?
Re: Jammed and I don't know why
Been here. Went crazy. Found the following fixes:
1. The pin that holds the bondtech idler gear in place tends to back out on the MK3 printers. Press it back in. Some people put a touch of epoxy on it to prevent it from happening again. This guy resolved his jamming problem with this fix: https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/another-heat-creep-jam-problem-t23781.html
2. Ditch the "Prusa" heatbreak and put a straight through or a MicroSwiss Nickle coated heatbreak in there. 3Dprinting nerd did a good video on this:
3. One day you should print out and use Butterworth Design's aligned extruder body. Idk why Prusa hasn't fixed this, but it helps dramatically for flexible filaments and PETG. It certainly will help with standarrd PLA as well. https://shop.prusa3d.com/forum/user-mods-octoprint-enclosures-nozzles--f65/modified-c1-r4-mk3s-parts-better-filament-path-and-t28334.html#p133076
Edit:
The filament sensor gets dirty over time which hinders it's performance. I try to give it a little blast of air every print to keep the dust off of it and occasionally I pull it out to clean it with a q-tip. I don't print with much transparent filament, but I print with white no problem. I've read other users having success with this solution too. Or heck...go for broke and print the Butterworth extruder body with the indirect configuration N4A (thanks Marin_au) and never deal with the sensor again!
Re: Jammed and I don't know why
Been here. Went crazy. Found the following fixes:
1. The pin that holds the bondtech idler gear in place tends to back out on the MK3 printers. Press it back in. Some people put a touch of epoxy on it to prevent it from happening again. This guy resolved his jamming problem with this fix: https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/another-heat-creep-jam-problem-t23781.html
Everything seemed pretty solid with the gears, but I can check again.
2. Ditch the "Prusa" heatbreak and put a straight through or a MicroSwiss Nickle coated heatbreak in there. 3Dprinting nerd did a good video on this:
Thanks for that vid. That they found retractions has an impact in the issue occurring rings true in my case. The majority of the prints I've done at 0.05mm were actually pretty simple single object prints where there would be maybe only 4 or 5 retractions per layer. These last two prints, however, have about 20 objects crammed onto the platter.
I do have a MMU on order, but who knows when I'll ever see it... Maybe I should consider the change in the meantime.
3. One day you should print out and use Butterworth Design's aligned extruder body. Idk why Prusa hasn't fixed this, but it helps dramatically for flexible filaments and PETG. It certainly will help with standarrd PLA as well. https://shop.prusa3d.com/forum/user-mods-octoprint-enclosures-nozzles--f65/modified-c1-r4-mk3s-parts-better-filament-path-and-t28334.html#p133076
After looking at the extruder this weekend and also trying (and failing) to adjust my belts I am considering picking up a roll of PETG and doing some of those upgrades. Would also be a good time to replace the heatbreak as well.
This is my first printer, however, and I bought it assembled so I'm still a bit nervous to rip it apart as I have a habit of ending up with extra parts at the end 😉
The filament sensor gets dirty over time which hinders it's performance.
Given that I'm not in an enclosure yet and the house isn't exactly spotless I was surprised at how clean that area was after reading reports from others about how dirty it can get. What little there was I blew out myself, but I'l try the compressed air approach too.
Since fiddling with all that the sensor does seem to be playing nice again (though I didn't push my luck with the filament that it was really having issues with).
Or heck...go for broke and print the Butterworth extruder body with the indirect configuration N4A (thanks Marin_au) and never deal with the sensor again!
Yeah the indirect sensor is definitely on my list when I start upgrading parts. Much like being nervous about fiddling with the hardware, I'm also not keen on playing with the firmware yet.
Re: Jammed and I don't know why
If this is your first 3D printer I would avoid MMU until rev...3....or 4. The current solution isn't quite robust enough for new users imo, however, there's plenty of veterans on this forum that will assist you with it. Most successful MMU users note that smooth transitions in the PTFE coupling/tubes helps performance. Filament getting stuck in the pressfit connectors and stuff is apparently an issue. A recent reddit post went deeeeeeep into MMU tuning.
The heatbreak is my most recommended swap. It doesn't even need to be microswiss, or titanium. A cheap, standard, straight through SS heatbreak has served me well in the past 4 printers I've used. The Prusa heatbreak was the first I've ever had issues with...especially in low flow/high retraction prints.
The indirect sensor mod from Martin_au (and incorporated into a Butterworth's Extruder Body) requires no firmware changes to my knowledge. It just makes the sensor detect a moving/rolling bearing instead of the filament....which is what the sensor is tuned for (seeing metal move, not colored filament). In my opinion, Martins solution is better than Prusa's own MK3S because the MK3S can't detect stalled filament from what I understand. It relies on filament physically not being present to "close" the switch and then trip the optical sensor. It's made more for filament running out, not filament jamming. The best solution should detect jams (non moving filament) as well as filament running out.
Re: Jammed and I don't know why
If this is your first 3D printer I would avoid MMU until rev...3....or 4. The current solution isn't quite robust enough for new users imo, however, there's plenty of veterans on this forum that will assist you with it. Most successful MMU users note that smooth transitions in the PTFE coupling/tubes helps performance. Filament getting stuck in the pressfit connectors and stuff is apparently an issue. A recent reddit post went deeeeeeep into MMU tuning.
Yeah I really want to do MM prints, but I keep going back and forth on if I should cancel my order or not. I think so far I've been leaning on "this printer has been so easy I'll hopefully have similar luck", but with these issues edging evermore (the job failed again tonight in the same manner) towards having to do some major work on it...
The indirect sensor mod from Martin_au (and incorporated into a Butterworth's Extruder Body) requires no firmware changes to my knowledge.
That makes it easier. I was reading about one last week after it started having sensor issues and it did require a new firmware. I definitely need to read up more about these various upgrades though as it looks like I'm at that point 🙁
Re: Jammed and I don't know why
2. Ditch the "Prusa" heatbreak and put a straight through or a MicroSwiss Nickle coated heatbreak in there. 3Dprinting nerd did a good video on this:
I watched this the other day and found it very interesting.
My filament sensor got switched off a long time ago. I run big filament spools now and also use scales to measure the spools to check if there is enough filament on them or work out when the need changing
Re: Jammed and I don't know why
So I finally kicked off a 3rd try on this last print again last night. Woke up to it still going strong, but earlier this after noon (about 15 hours into the print) the extruder started grinding again 🙄
Of course at this point even if I don't have any more issues I don't think there is enough filament left to complete the print. As it appears that Prusa has given up on that filament in favor of Prusament I expect that means I'll actually have to redo all these prints (about 100 hours worth) as I don't know if I can find a good color match 🙁
I hadn't question the filament itself as my other roll of the Silver was flawless and produced the cleanest prints I've gotten, but my wife prompted me to rethink that view. When I bought the printer I ordered it with a second roll (this one) of the Silver and a Black roll in addition to the Silver the printer came with. As mentioned the other Silver roll was perfect, but about 3/4s of the way through the Black roll it went to crap and ruined the print (0.2mm layers) it was running (terrible adhesion, mid print warping, just terrible). Same gcode with Inland PLA ran perfectly. This Silver roll is vaguely at the same point in remaining filament. Coincidence? Bad luck?
I'm trying to run the print now off a SuperFila roll (wrong color though) to see what it does. If it works OK then I think I have to assume I somehow ended up with another bum roll from Prusa 😕
Re: Jammed and I don't know why
Gnat: Wear marks on you heater block hint the nozzle was set too deep into the block. The HEX portion should never contact the aluminum. The heat break needs to be turned in a bit more. This explains the filament leakage to the threads. Normally you leave the nozzle out about 1/4 to 1/2 turn, then snug the heat break to the nozzle position. Then heat and torque the nozzle at temp to the 3NM spec. I doubt this is what you are fighting, but is an area for adjusting when you get a chance.
When you had the hot end apart, did you happen to blow compressed air up through the heat break and PTFE? Debris trapped there has caused me all sorts of intermittent jams that were hard to explain. In my case it all started with Glow-In-The-Dark filament... nozzle plugged up, then the Bondtech shredded it creating plenty of dust that fell down the PTFE. I fixed the nozzle plug with a few cold pulls and switched back to normal filament; but had jams that happened at odd places, and cold pulls never fixed them. Plus, I could extrude 100 mm of filament immediately after a jam had ruined a part - doing nothing between the abort and flow test. I was completely flummoxed. When I replaced the nozzle (what else could I do?) I blew air around the filament sensor and down the filament path, then on a lark blew air up the filament path and was greeted with a mushroom cloud of dust. The jamming stopped and I've been printing ever since without any under-extrusion or jams (many months). The whole dust and debris thing wasn't at all intuitive because I can't imagine all that material inside the heat break. Had I not seen the cloud of dust I'd argue it were impossible.
Re: Jammed and I don't know why
Haven't tried the air trick yet as A) I haven't had the nozzle off since you mentioned that in another thread and B) I don't have canned air handy ATM. Thanks for reminding me though so I can add it to my list of stuff I'm ordering in the next few days.
What wear marks are you referring to? The dark areas around the hole for the nozzle? If so I think that is simply residue from the filament that leaked out the sides.
Filament coming out the side is not a normal occurrence for me at all. The pictures I've included here actually represent the only time it has happened. I missed that the nozzle is supposed to be torqued to 3nm, but I did see that it is supposed to have the gap. I've just been making sure it's finger tight (using a socket and extension without the driver) which leaves the requisite gap.
Re: Jammed and I don't know why
Highlight looks like a metal-metal contact ring ... could be tool marks from removal, but seems too close to threads for that.
Re: Jammed and I don't know why
Well the print worked flawlessly with different filament, so at least part of the issue appears to be filament related.
Unsurprisingly the new silver filament I ordered looks nothing like the online pictures so it doesn't match and I'll have to re-print all the successful parts again (about 100 hours of printing) 🙁
Re: Jammed and I don't know why
Been here. Went crazy. Found the following fixes:
1. The pin that holds the bondtech idler gear in place tends to back out on the MK3 printers. Press it back in. Some people put a touch of epoxy on it to prevent it from happening again. This guy resolved his jamming problem with this fix: https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/another-heat-creep-jam-problem-t23781.html
2. Ditch the "Prusa" heatbreak and put a straight through or a MicroSwiss Nickle coated heatbreak in there. 3Dprinting nerd did a good video on this:
3. One day you should print out and use Butterworth Design's aligned extruder body. Idk why Prusa hasn't fixed this, but it helps dramatically for flexible filaments and PETG. It certainly will help with standarrd PLA as well. https://shop.prusa3d.com/forum/user-mods-octoprint-enclosures-nozzles--f65/modified-c1-r4-mk3s-parts-better-filament-path-and-t28334.html#p133076
Edit:
The filament sensor gets dirty over time which hinders it's performance. I try to give it a little blast of air every print to keep the dust off of it and occasionally I pull it out to clean it with a q-tip. I don't print with much transparent filament, but I print with white no problem. I've read other users having success with this solution too. Or heck...go for broke and print the Butterworth extruder body with the indirect configuration N4A (thanks Marin_au) and never deal with the sensor again!
Definitely going to be looking into some of these to combat my own mystery jam.
Re: Jammed and I don't know why
Well the print worked flawlessly with different filament, so at least part of the issue appears to be filament related.
Unsurprisingly the new silver filament I ordered looks nothing like the online pictures so it doesn't match and I'll have to re-print all the successful parts again (about 100 hours of printing) 🙁
I would still encourage putting a new heartbreak in there unless you're going the MMU route. I feel like the low layer height you're printing with would be more reliable with it regardless of filament type. But hey, if it keeps on working for you then there's really no reason.
When I was going through this I was printing with 3D850 which has been noted to jam a little more than 3D870 and 4043D. Oddly enough, Prusa says right on their product page that Prusament (4043D) is the only filament approved for 0.05mm printing.
https://shop.prusa3d.com/en/prusament/711-prusament-pla-prusa-galaxy-black-1kg.html
Definitely going to be looking into some of these to combat my own mystery jam.
Good luck! The MK3 is an amazing printer once you get the few little kinks figured out.
Re: Jammed and I don't know why
Well the print worked flawlessly with different filament, so at least part of the issue appears to be filament related.
Unsurprisingly the new silver filament I ordered looks nothing like the online pictures so it doesn't match and I'll have to re-print all the successful parts again (about 100 hours of printing) 🙁
I would still encourage putting a new heartbreak in there unless you're going the MMU route. I feel like the low layer height you're printing with would be more reliable with it regardless of filament type. But hey, if it keeps on working for you then there's really no reason.
Yeap I have a new heatbreak already. Waiting on the PETG anf PTFE tube to show up and I'm gonna do the suggested modified extruder with the bearing based filament sensor.
Also going to add the (better) adjustable Y-Axis (my Y-Axis is way too tight and I it won't loosen enough) and nyloc bed leveling upgrades too (bed is not quite level).
As long as this new filament is working, however, I'm gonna try to get this printing done before I tear the printer down.