Jamming filament and driers
Hello, new XL has been printing 2kg+ now and extruder 1 has blocked for few times. What does your experienced eyes see, is this my setup something that would lead to issues I'm experiencing? Changes today for trying to make setup better are elevated driers, they were at the bottom of the enclosure, and also I added today the roll holder to support filament line. Drier outfeed hole is very free and overall friction is minimal. Next I'm testing to use primarily extruder 2 to see if it behaves differently. Filaments are brand new Prusament PLA and not older that a week. I used these driers for two years with Ender 5+ / Micro Swiss direct extruder without issues. I'm not newbie in general but XL is new for me.
RE: Jamming filament and driers
PLA + enclosure = heatcreep
Maybe it worked fine with the ender but the XL bed is on another level in terms of heat output. At the very least I'd move the two extra heatsources (driers) out of the enclosure and see if that's enough. Otherwise look into venting more of the trapped heat if you want to keep the enclosure.
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RE: Jamming filament and driers
Hello BaconFase, I didn't mention that the dryers haven't been used yet. They work just as roll holders. This PLA is so new that drying isn't needed. So, additional heat could be ruled out.
The same print is now almost ready with Nextruder 2, so it's going to be the first success for the long run if it goes an hour more. I also read from another thread that this jamming has been an issue quite widely earlier with fw6.02 or 6.03. I use latest 6.1.2
Posted by: @baconfase
PLA + enclosure = heatcreep
Maybe it worked fine with the ender but the XL bed is on another level in terms of heat output. At the very least I'd move the two extra heatsources (driers) out of the enclosure and see if that's enough. Otherwise look into venting more of the trapped heat if you want to keep the enclosure.
RE:
Couple points:
- Make sure your printer is new enough to have the PCCF idler levers and belt retainer. PETG levers will irreversibly soften in enclosures, then you'll get jams due to not enough pressure on the filament. The PCCF levers are matte dark grey, PETG is shiny black. The belt retainer sits under the black plastic cover with the PrusaXL print (subject has been discussed in other threads, and PR send these parts out with their enclosure to retrofit older printers).
- I'm using the same driers. I recommend using one of the wedge pieces on printables to keep the lid open a tiny bit, this improves drying dramatically.
- Use something like this: https://www.printables.com/model/884185-prusa-xl-adjustable-filament-sensor-holder
- Your electronics are inside the enclosure, which is terrible. Find a way to cool the board actively using air from outside the enclosure. At about 95°C MCU temperature the printer will pause the print, which happens even with the electronics outside an enclosure if ambient temp is too hot. The board sits in a tiny box with almost no ventilation, it will heat up quickly. E.g. mod something like this: https://www.printables.com/model/859870-improved-prusa-xl-buddy-cover
- As baconfase said, with PLA you'll have to keep the enclosure open as much as possible.
- The official PR enclosure doesn't get too hot and has a lot of holes by design. It only gets to about 44°C for me with ABS even if ambient is already 35°C. Prints are great though. I would advise to make sure your enclosure doesn't go much higher, we can assume they have reasons for this limitation. I'm suspecting the Dwarf board MCU can overheat (its temp is monitored).
RE: Jamming filament and driers
Thank you, @ntdesign! You make many good points. The printer is less than a month old, so I assume early-production issues are covered, but I'll check. I did order today a Thermaltake AC-010-B51NAN-A1 fan controller and will install fans in the enclosure. I have some spare 120mm Noctua PWM 12V fans that should do the job. As for fumes, I don't care since this building and room is one nobody stays long in.
The infeed fan should perhaps be behind the printer to supply colder air directly to the electronics and who knows if install such direct fan too some day. Drier ventilation is one topic too which has been on mind but since real drying needs have not been occurred it is postponed. Leaving lid a little open is simple as told.
The print with 2nd Nextruder completed fine. I will use it for now to see if there is any difference.
The fan controller is this: https://thermaltakeusa.com/products/commander-ft-touchscreen-fan-controller-ac-010-b51nan-a1
Couple points:
- Make sure your printer is new enough to have the PCCF idler levers and belt retainer. PETG levers will irreversibly soften in enclosures, then you'll get jams due to not enough pressure on the filament. The PCCF levers are matte dark grey, PETG is shiny black. The belt retainer sits under the black plastic cover with the PrusaXL print (subject has been discussed in other threads, and PR send these parts out with their enclosure to retrofit older printers).
- I'm using the same driers. I recommend using one of the wedge pieces on printables to keep the lid open a tiny bit, this improves drying dramatically.
- Use something like this: https://www.printables.com/model/884185-prusa-xl-adjustable-filament-sensor-holder
- Your electronics are inside the enclosure, which is terrible. Find a way to cool the board actively using air from outside the enclosure. At about 95°C MCU temperature the printer will pause the print, which happens even with the electronics outside an enclosure if ambient temp is too hot. The board sits in a tiny box with almost no ventilation, it will heat up quickly. E.g. mod something like this: https://www.printables.com/model/859870-improved-prusa-xl-buddy-cover
- As baconfase said, with PLA you'll have to keep the enclosure open as much as possible.
- The official PR enclosure doesn't get too hot and has a lot of holes by design. It only gets to about 44°C for me with ABS even if ambient is already 35°C. Prints are great though. I would advise to make sure your enclosure doesn't go much higher, we can assume they have reasons for this limitation. I'm suspecting the Dwarf board MCU can overheat (its temp is monitored).
RE: Jamming filament and driers
The lever seems matt dark grey, so perhaps these are PCCF. Today, I found a potential cause, and I'm looking after it now: Dock 2 did run fine over a 1kg roll, and then I added a Primavalue cardboard roll to the drier. It ran fine overnight, but after about 8 hours, the filament got stuck. I pulled filament from the drier, and it ran well, though. Then I tried to pull from the extruder end of the PTFE tube, and it didn't roll well at all. Massive force was required. The reason looks to be that the roll climbs over the bearing bars where the roll sits in the drier and then is wedged in between the roller and the ceiling of the drier. And when you observe the thing, the roll has already fallen back down. So horizontal pull, especially for lightweight roll, may be an issue. Now, I proceed without driers and see if it helps.
RE: Jamming filament and driers
It is almost certain that the issue is on the roll end, at least this last time. I watched from the camera, and the dryer leaned forward millimeters, and then the error message appeared on the screen. The temporary stand is so elastic that it moves and reveals if the dryer wants to fall. If driers are not taped to the "stand," they will probably fall. It is taped down to prevent falling when reloading, and the lid is open.
RE: Jamming filament and driers
Some new observations. I removed both driers, and now the rolls are on the original holders. Extruder 1 seems to get stuck in a few hours or minutes. Unloading and reloading clears the issue, and print proceeds fine for some time. I changed the filament roll, and no effect, it gets stuck.
These images are from the latest unload. I see apparent deformation and tight corners. The blob at the end of the filament is 2.15mm in diameter. Should it be?
RE: Jamming filament and driers
Nope, that isn't good. If that's PLA then the temperature in your enclosure is just too hot. The filament end looks ok, but the bends further up indicate the gears are too warm. Check the heatbreak temps (Tune->Info->Sensor Info). Mine are < 60°C, even with ASA after a few hours when outside temps are in excess of 35°C. Inside enclosure about 45°C. PLA will already soften under pressure around 60°C. Maybe try dialling the idler pressure back a bit, mine were all a bit random from factory. Additionally PLA at +60°C gets a bit sticky, which increases friction in the PTFE. You have to keep in mind the heatbreak fan already pulls in warm air and is not very efficient to begin with.
If you still use the little PTFE inserts that come with the driers, these add too much friction. I drilled mine open with a 2mm bit. This helped but wedging it open and using that opening is better.
RE:
I added H&T to the enclosure's ceiling, and the temperature barely exceeded 30C, so heat is most likely not the issue. The printer has been doing fine for a few days. I tightened the feeder two bolts for two full rounds, and the feeder had more force to pull before slipping.
So, now it is doing fine, and the driers have been removed completely to narrow down the root of the issue.
It seems the root cause of these feeding issues is the filament sensor and the excessive force required to pull the filament. 20N and 28N are a lot. The variation of force required is almost 50% between the two extruders. I pulled a meter or so of filament through a Bowden tube with a fishing scale while waiting for it to stabilize, and that's what it was while on the move. It was even more before the filament started moving. Strangely, 20N was required for the extruder, which created issues, and 28N was for the extruder, which was fine. But static friction matters, and I didn't have gears to measure it correctly.
Nope, that isn't good. If that's PLA then the temperature in your enclosure is just too hot. The filament end looks ok, but the bends further up indicate the gears are too warm. Check the heatbreak temps (Tune->Info->Sensor Info). Mine are < 60°C, even with ASA after a few hours when outside temps are in excess of 35°C. Inside enclosure about 45°C. PLA will already soften under pressure around 60°C. Maybe try dialling the idler pressure back a bit, mine were all a bit random from factory. Additionally PLA at +60°C gets a bit sticky, which increases friction in the PTFE. You have to keep in mind the heatbreak fan already pulls in warm air and is not very efficient to begin with.
If you still use the little PTFE inserts that come with the driers, these add too much friction. I drilled mine open with a 2mm bit. This helped but wedging it open and using that opening is better.
RE: Jamming filament and driers
Some people have reported too much friction in the side sensors, mainly in the older models. Mine are ok except for TPU. They are not really necessary, but possibly there is just some issue with your printed parts. If the hole where the spring sits has some gunk in it, you'll end up with too much compression. Earlier models also had tighter PTFE tubing which created problems, can you measure your ID? Maybe they have some old stock floating around.
I generally wouldn't overtighten the idler, it creates mechanical stress and problems with retraction. I'm guessing that's why your filament looks so bendy.
RE:
Did you try other PLA from another brand? I had many issues with my printers and prints when using PLA from Primacreator. All of these issues are gone with other filament.
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RE: Jamming filament and driers
Saphir, I've used two different PLAs with the same effect. One was Prusament PLA, and another was some generic PLA. Now, everything runs smoothly after I tighten the feeder. The main reason, I assume, is the too-high force required to pull the filament through the horizontal sensor. I'm waiting for some parts for an upgrade attempt, or at least a change attempt if not an upgrade. I try to reduce friction with the original sensor.
Did you try other PLA from another brand? I had many issues with my printers and prints when using PLA from Primacreator. All of these issues are gone with other filament.
RE: Jamming filament and driers
ntdesign, I fully agree about the force and lifetime of mechanics. Therefore, I try to reduce friction with a new design once the parts arrive. Tube ID looks quite loose for the filament, but I haven't measured it yet. Pulling filament causes almost no friction if I pull filament through the tube alone. Adding a roll to the system generates much friction since the filament is pulled against the inner curve of the tube. By adding the horizontal sensor, the force increases significantly since all the force required to pull makes the filament sit tighter against the inner curve of the tube. It is the "rope friction, or belt friction," as a term.
Some people have reported too much friction in the side sensors, mainly in the older models. Mine are ok except for TPU. They are not really necessary, but possibly there is just some issue with your printed parts. If the hole where the spring sits has some gunk in it, you'll end up with too much compression. Earlier models also had tighter PTFE tubing which created problems, can you measure your ID? Maybe they have some old stock floating around.
I generally wouldn't overtighten the idler, it creates mechanical stress and problems with retraction. I'm guessing that's why your filament looks so bendy.
RE: Jamming filament and driers
If you want my personal opinion, Prusament PLA is not that great. It causes all sorts of problems in multicolor prints for me, and it's hard to deconvolute different issues in your case. I normally use up the spool you get with the printer asap. You're better off testing with random cheap stuff you know works well.