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.
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.