Hi all. This is an update to this post. I don’t know what else the community can do to help, but I figured I’d throw some more content up there and give something bored people to look at.
Since the last update on that post, I tried working on the printer in freezing temperatures (not really but it’s cold in this house) with extremely precise practices on assembling the hot end (the same hot end I had haphazardly assembled dozens of times and printed with zero issues) and yielded zero progress. Today, I tried a brand new PTFE lined heat break, along with a brand new Capricorn Bowden tube (I already had one but I needed more tubing for the heat break). Clogging in the same exact way in roughly the same amount of time as every other attempt. It’s as if I’ve not tried anything, literally nothing is effecting the results.
I considered ordering a fancy micro-swiss or ed3 hot end, but at this point, including the stock hardware, I’ve gone through 6 heat breaks, 3 heat blocks, a half dozen nozzles and a foot of Bowden tubing, none of which did anything to fix my problem (or even make it worse). I would look to the extruder, but I outlined in the previous post the testing I did to rule that out (able to run >1m of filament at high and low speeds through the Bowden tube).
I’m at the end of my wits. Perfectly good printer cranking out multiple high detail prints a day, now completely useless over something so stupid as clogging. Where the hell else can I look? Could it possibly be some sort of software/firmware issue, where Klipper isn’t sending or receiving the right commands or something? I know my slicer settings are at least good enough because I’ve tried both prints that have completed dozens of times as well as new prints with drastically reduced retraction. Do steppers need to be tuned over time? I don’t think it makes sense that after a year it’d suddenly become so uncalibrated it’s unusable, and when I tried calibrating it before I was just unknowingly calibrating against mild clogs, but I don’t know where else to look.
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Hello, I suggested heat creep in your last post, which didn’t end up being the issue. I don’t remember if anyone suggested it, but have you tried checking the bowden assembly, on the motor side? Whether the stepper works, or the gears wore down (I’m pointing towards this), or there are clogs somewhere in the mechanism, even some dust that accumulated where it shouldn’t had. Or did you change settings like the current limit on the steppers? If that’s controlled with a potentiometer on the main board, maybe it got turned down for some reason (if so, I’d try to understand why’s that). I don’t know how Klipper handles motor drivers where current limits are controlled in software, I know that Marlin has a dedicated submenu in the Configuration>Advanced Configuration. If you reflashed the firmware, maybe the settings where in the eeprom and did not get transfered over or got overwritten in the flashing process.
I remembered that on a couple different printers I had the same problem as you, and it came down to damaged/untightened nozzles (which you excluded already) or wore down gears or, on the printer I’m working on right now, too low current limits which made the stepper skip steps somewhat randomly
I think I’m going to start poking around the extruder side of things. I really don’t know what to look for, as everything seems to be working over there (outside of prints anyways…). Things look clean, no clicking, gears don’t appear to be damaged… I’ll take a dive when I get home.
I don’t think anything got messed up during the flash because it had been working for a month or so running Klipper. I don’t know if stepper motors need to be recalibrated every once and a while, but it’d be weird for it to go from “working perfectly fine” for over a year to “completely unusable” literally in between two prints.
Thanks for your continued suggestions.
Any suspicion of the heat cartridge failing? Might work long enough for a pid tune but not be able to maintain temp? I’d also look I to the extruder, once you put the nozzle on its working much harder.
I suspected a faulty cartridge, but that would reflect on the temp chart no? Unless the thermistor was somehow failing perfectly to match the change.
I think I do have to look to the extruder. I’m nervous about it because I don’t know anything about how to maintain or diagnose them, but I guess there’s a time to learn everything.
Also dumbest idea, have you tried a brand new spool of PLA? Just to exclude an incredibly wet filament. Because that can cause all sorts of problems
I’ve tried a few different rolls, 2 of which were used for successful prints literal minutes/ hours before the issue sprung up.
I’ll admit that after a week or so of diagnosing this issue I’ve mainly switched to cheap crappy filament to run extrusion tests with (I’m extruding 500-1000mm into the air at a time), but the few times I’ve gotten far enough to try an actual test print I’ve put my good stuff back on and it clogs up just the same.
One thing you haven’t mentioned replacing is the fan for the heat beak itself. May be worth giving a try.
I considered that, but the fan is still spinning at a good speed and I can feel a lot of air being pushed by it. Additionally, one of the things I tried was pointing a desk fan at the printer (outside the enclosure, with the house ~5° cooler than it normally is), with no change in results.
This would drive me bonkers but stubborn enough to want to dig into the “what” of it.
If it were me I’d setup some kind of makeshift jig that holds the nozzle and hotend with cooling fan out from the rest where I could hand feed filament in.
So you could bring the temp up, wait a few minutes, then push and get a feel for what’s going on. Then wait a few more minutes and do it again. Feel resistance, up the temp, and repeat.
See if there’s some relationship between temp, extrusion, flow, etc that isn’t obvious otherwise.
You know, I actually really like your hand feed idea. Now that you mention it I was thinking it was more difficult than normal to hand feed filament through the nozzle by pushing it from behind the extruder and holding the arm open. I’ll try removing the Bowden tube from the hotend and running filament through it by hand to see if I can replicate the clog. Actually, if I can get a clog doing that, it would eliminate the extruder as a problem as well.
Thank you for this suggestion. I’m trying it first chance tomorrow.
Any chance you post some pictures?
Looking at the filament part that was in the extruder and in the nozzle might help identify an issue or exclude some other possible issues. Also, looking at hotend and extruder and motherboard might be usefull here.
Do steppers need to be tuned over time?
No, but its worth to check at this point. Stepper drivers can die, overheat, cable can be damaged, motor can be damaged, overheat… If stepper was tuned to barely push the filament and something added extra resustance (friction) it might explain why issue started. If driver is overheating you can probably just add a small cooling fan or even a heat sink. Why I go in detail here? Because if something happens every time after about the same amount of time, it sounds like overheating issue, especially stepper driver, but I might be wrong. If filament was well grinded by extruder teeth, the issue is probably somewhere after extruder
Bonus question: did you check filament diameter and how consistent it is?
I suspected the extruder of overheating, but it’s still cool to the touch even after the nozzle gets clogged and the extruder has been clicking for a while.
If filament was well grinded by extruder teeth, the issue is probably somewhere after extruder
This is what I’m thinking too; if extrusion was the issue, it would make more sense that filament would not be reaching the nozzle, but the opposite is happening, filament reaches the nozzle can’t get out and the extruder continues trying to push filament, either grinding it down or clicking back and forth, then as soon as the clog is cleared pushes filament like normal. (I’ll set the printer to extrude 1m of filament, it’ll clog, while it’s still trying to extrude I’ll clear the clog or disconnect the Bowden tube then filament keeps going)
Ok, then I don’t think it’s overheating, but imagine your stepper driver is set to too low current:
While extruding there might be extra friction involved in the heat break which can suddenly become too much for extruder. Solution is to increase stepper driver current (it can be software approach - klipper, or HW - small screw pot on the driver itself). Stepper motor is heated according to the current you’ve set, almost not related to the speed of the motor. In my experience extruder stepper motor is usually hot to touch, so that might be another reason to check stepper driver settings.
Maybe adding heat break requires to adjust stepper driver current in your case. Or maybe FW update changed the values. Its just a guess, but its not hard to check that. Basically you reduce the current to have obvious skipping, then boost current untill skipping stops, then increase a bit more to be on the safe side, then check is your motor or stepper driver too hot (its usually hot enough to be able to hold a finger on the motor for few seconds only).
I think it’s best to spend enough time on extruder first and not moving to hotend before you are completely sure extruder is working fine. Stepper motors are quite powerfull, extruder can usually grind the filament or push the bowden tube from its position before stopping, even when clog occurs)
Hm, ok what you’re saying makes sense. I am remembering that my extruder motor used to get pretty hot after long prints; since the jamming issue the extruder hasn’t been spinning for more than a few minutes at a time, but maybe it should be a bit warmer than cool to the touch. I have a few other things I want to try, if those don’t give me any info, I might try running a long print with no filament (or disconnecting the tube and extruding cold filament) and seeing if the extruder’s temp changes at all. Thanks for the advice.
