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.
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.
Take out the extruder stepper and rotate the shaft by hand and feel if there is binding at any point. I think I mentioned I had this same issue on my direct drive printer in your previous post. It would work fine until it didn’t and randomly act like the nozzle was clogged. When printing, I think the load on the motor is going to be greater than feeding filament through into open air, which may exacerbate the problem.
You’ve xhecked the hotend a bunch of times so I would focus on other areas. Something else may have broken at the same time as your nozzle swap which may just be leading you on a wild goose chase.
I got pretty busy today and didn’t have time to dig into the extruder, but taking the stepper out and rotating by hand is good advice that I wouldn’t have tried.
I took a slow motion video of the filament and extruder with the extruder arm tightened, so the extruder would click when it clogs instead of just grinding over the top of the stuck filament. In the video, you can see the extruder is backing up when it’s making that ticking sound. I’m assuming this is some sort of safety thing baked into the stepper controller? Like the voltage to the motor is getting too high, there must be a jam, back off and try again kind of deal? I don’t think that’s that cause, as it only does it when I intentionally tighten the extruder arm beyond normal use to create the clicking, and it clogs either way, just curious if it’s normal behavior.
I don’t know a ton about their design, so I could be wrong, but I believe with Trinamic drivers, they typically have current limits set in the firmware that will cut power if they exceed the limit. It could be jamming and just naturally springing backward as it occurs and power is cut.
Rotating by hand, you’ll feel the magnets inside giving some natural resistance (like you’re hitting notches) but it should be consistent and smooth otherwise. If you feel any extra resistance at any point in the rotation, I’d just swap it out or disassemble it and look for debris like plastic shavings.
That sounds more like what is happening. The “click” is probably the moment the power gets cut.
I’ll try the rotating by hand thing when I get back home. Someone else recommended me to try feeding the filament by hand and seeing if the clog occurs that way, so I’ve got a few things to try out. Thanks again for the advice.