Hi everyone, I'm having constant clogging issues with my printer that sprung up out of nowhere. I'm running out of things to test.
The printer had been running several prints a day for several days when I decided to change nozzles for one print. Ever since then (~2 weeks ago) i have not completed a single print, due to clogging. I have tried:
Replacing the PTFE tubing in my hotend.
Replacing the nozzle. (I've used a handful of nozzles, all with the same results)
Trying different filament.
Replacing the hot end with an all metal hot end, trying three different heat breaks from two manufacturers.
Removing the printer from its enclosure to ensure proper cooling.
Adjusting extrusion tensioner.
All the other basic obvious stuff like making sure there's no blockages anywhere (whole hot end and nozzles have been soaked in acetone, torched, brushed etc).
The printer will seem to work fine for a little while before either slowly failing to extrude until it completely jams, or it completely jams all at once. I don't think it's heat creep, because I tried setting the nozzle to printing temp, letting it sit for half an hour or so and running filament through it and it had no issue, whereas prints usually start to fail within the first 10 minutes. It also doesn't have anything to do with my print settings because I'm able to get it to clog sometimes by just running the extrude command.
I'm completely at a loss here. I don't know what else to try. Does anyone have anywhere else for me to look?
Update: I tried detaching the heat block from the rest of the printer and running filament through the (cold) heat break, and it got clogged. There was a small bit of filament adhered to the inside of the heat break. So it's apparent that's where the clog is forming, it's just a matter of finding out why it's happening. Everything seems to point towards heat creep, but even when I intentionally try to heighten the conditions that to cause heat creep I can't intentionally replicate the clog. I'll keep experimenting down that route, though.
Update 2: After clearing that clog, I noticed the short piece of Bowden tube between the top of the heat break and the top of the heat sink was slightly too short. I modified the heat sink to bypass this short piece altogether; the Bowden tube now goes directly from the extruder into the heat sink to the top of the heat break. I also applied a thin layer of thermal paste to the outside of the heat break to ensure good contact/ heat transfer with the heat sink.
After doing all of this, I ran a PID tune and, with my AC set to lower than average, started extruding filament. After extruding ~300mm of filament, I tried a few nozzle and filament swaps using very careful techniques to avoid leaving any residue. I'm able to pull the filament out in a solid piece to where I can see light through the nozzle afterwards. Then, finally, out of the blue, the clicking returns. Another clog. I wasn't able to remove the filament as cleanly this time to inspect the clog, but I'm strongly suspecting heat creep at this point, despite going above and beyond to mitigate it. It's quite late though and I've got work tomorrow so it'll have to wait until then.
Hm, I have not. If my printer still reports stable temperatures, is a PID tune necessary? I feel heat isn't the issue as filament still oozes out of the nozzle when it clogs, but if it has something to do with wildly unstable temps then maybe it could be the cause? I will say that the filaments I've tested are all PLA and have successfully extruded at temps as low as 170, and I've been experimenting at around 200, so unless the nozzle temp is off by over 30 degrees (which I would've noticed at idle temps) I don't think low temps could be causing it
I wouldn’t think it would create clogging scenarios usually but the PID tune does allow the firmware to learn the relationship between power applied to the heater and when the thermistor registers temperature changes.
Since you’re getting clogging and after a few minutes that could be from heat creep and there’s always the possibility that it’s being over zealous on the temp since it’s applying heat, not seeing enough increase, applying more heat.
Worth a try since you’d normally want to do a PID tune when you change anything related to it.
For me I do a bed tune when I change plates, and an extruder tune when I change any of the extruder hardware (fans too). If I’m printing in a material where the part fans will be high enough out of the norm I’ll do one with the fan at the given speed (e.g. my dual 5010 fans anywhere about 80% will blow back to the heater block even with creative use of Kapton tape to stop drafts and a PID tune helps mitigate any issues there.