Clogged Nozzle?
Hello,
I have been printing almost constantly all summer, and all my prints were coming out perfectly until last week (I am using the MK2S MMU upgrade). Now, every time I run a print, it works for a bit, but after a few minutes or sometimes up to a few hours, filament stops coming out of the nozzle and the extruder starts clicking. A few days ago, it made it 33:40 into my 34 hour print before it failed. I have tried clearing out the nozzle and done cold pulls, etc., but nothing seems to be fixing the issue. I took apart the hotend, but I do not see any obstructions. I have tried a variety of filaments, all which are giving me the same issue. I even swapped hotends and that did not fix the problem. My extruder gears are clean, and the extruder seems to be working fine when I disconnected it from the hotend and watched it pull the filament through while I ran a print. I also tested a different extruder (I have 4 of them to try), and the same thing happens with each one. I also printed the collet clip to hold the PTFE tube in place better, which at first seemed to work, but after a few hours the print failed again. Does anyone have any more suggestions? I seem to have tried everything I've found online. Usually I am pretty good at getting my printer back up and running, but I'm at a loss this time.
RE: Clogged Nozzle?
Apparently I can't edit my own post, but here is a photo of some of the prints I've started but cancelled. As you can see, the threads are thinner than usual, and then get thinner and thinner as the print goes on until filament stops coming out entirely.
Have you tried tweaking the extruder idler tighter by about a quarter turn?
Cheetio,
RE: Clogged Nozzle?
That does not seem to be the issue. I have tried a variety of different extruder tightnesses, and the extruder continues to make clicking sounds and grind the filament. Instead of sucking the filament in smoothly, it sucks it in a bit, and then it pops back out of the extruder. That’s what made me think the nozzle was clogged, but there is no sign of it being clogged or ever having been clogged…
You tried a different extruder - does that include the stepper motor?
If you used the same stepper try turning it by hand with power off - is it smooth? You should feel the steps but no grating and no variation...
Cheerio,
RE: Clogged Nozzle?
I have 4 different extruders, each with their own stepper motor, and all 4 are having the same issue. The motors seem to be turning smoothly.
OK, you tried several filaments, presumably they are all stored in the same fashion; perhaps this is a humid atmosphere problem. Try drying a filament just before printing.
Cheerio,
RE: Clogged Nozzle?
All my filaments are stored in an airtight container with silica gel and desiccant. Is there a better way I should be drying/storing them?
That's fine for storage but it won't remove moisture already absorbed. Some filaments can deteriorate from perfectly dry to almost unprintable in just the few hours they are open for use. The water boiling off messes with extruder pressures.
There are lots of threads here about drying and dryers but if you have an electric oven with accurate low temperature control you can dry one enough for a test, most people who have a serious problem buy a food dehydrator or similar for regular use; mine is running now.
Cheerio,
RE: Clogged Nozzle?
Ok, thanks! I'll look into that. In the meantime, I've noticed that often when it stops extruding, it'll drip a glob of filament much like in the video that stays sticky and never hardens, even after many hours. Do you think this has something to do with my printer settings, and might be contributing to my issues?
Excess moisture can also cause dribbling. What material are you printing?
Cheerio,
RE: Clogged Nozzle?
I am printing with TPU. The video that I sent above was from a print done with a roll straight out of the package (failed after ~30 mins). It seems like when I finally get the TPU out of the nozzle, the PLA prints ok, but I haven't done a long enough PLA print to confirm that yet. I have one going currently that will hopefully answer that question. I had been printing with TPU for a while (about 10 30 hour prints), and it was all going smoothly until recently when I started noticing the globbing. I have tried multiple different rolls, though (same brand), all having the same issue.