No extrusion on print
My Mini has been running great for a couple of months now, and survived the constant print load for the holidays. Now I'm running into my first issue with it. I think I might be running into the PTFE tube in the hotend shrinkage issue, but want to double check before I start disassembling. Here's the issue:
Running a print job everything was going fine, but the extruder has been starting to make clicking noise. Then it simply stopped pushing plastic, so the job failed. I got the filament out of the machine after some struggle, and ended up doing a cold pull on the hotend in the process. The filament appeared to just stop moving and the feed gear chewed a divot in it.
I disassembled and cleaned the extruder, then reassembled. I've done this twice now. Gear mesh still looks perfect.
I can run the bed level calibration and it looks good. In Octoprint, I can run from the Control tab extrude and retract and it works fine. I have tried running a print job with no filament and there is an occasional minor click, but on the whole it runs fine. I stick some filament in while that is going and it's feeding normally and quietly.
When I load filament, and purge, then run a job, it stops extruding correctly. The purge line usually runs ok, and the brim usually starts ok. Then it stops extruding and I just get little tiny blobs of plastic.
So it seems like an issue with pushing molten plastic through the nozzle. But it's not a full clog. So does this sound like time to replace the PTFE tube inside there? I want to be sure I need to take it apart before doing it.
Mini+ (kit) - Revo Micro | Antler Cooling | WiFi (4.4.0RC1)
RE: No extrusion on print
Don't be intimidated by changing out the tubing in the hot end, it isn't that difficult a job. Follow the instructions on this site, they're pretty comprehensive and detailed. Once you've done it a time or two you can do the whole thing in just a few minutes. The critical concept is during assembly, you need to insure the tubing is under the proper compression. That's the purpose of turning in the top fitting then backing it off 1/4 turn, when you lift the heat break into position and tighten the grub screws turning down the top fitting the last 1/4 turn sets the compression.
Be prepared to do a cold pull if there is any filament where it doesn't belong.
Cheers
-Bob
Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit
RE: No extrusion on print
Hi
firstly, let us confirm the extruder is pushing the filament correctly.
remove this tube with big nut.
Then print normally.
Hopefully everything will move as normal and the filament will keep moving out of the tube.
This means the extruder is pushing the filament as normal.
If it failed here, then the extruder is the problem.
then i will suggest taking apart the extruder and put it back again.
Guide there at step 33. Assembling the Extruder motor
https://help.prusa3d.com/en/guide/3-x-axis-extruder-assembly_199519
2)
then if extruder is ok, then the problem is at the hotend area.
I will suggest to do a cold pull.
guide here. https://help.prusa3d.com/en/article/cold-pull-mini_126399
3)
If cold pull still fail, then try to google/youtube for other solutions.
there are many other solutions to this which i cant think of now.
RE: No extrusion on print
Thanks. I did locate the clogged hotend troubleshooting page after posting (naturally). I'll go through that later today.
KTH, I did test the extruder on its own. Removed the Bowden tube, then ran the load filament process from the printer. I also used the Octoprint control tab to manually tell it to extrude & retract a few times (even was able to measure commanded 100mm extrude vs actual material fed: 98-99mm). Lastly, I started a print job with no filament, then fed some in while it was going. In all cases, the extruder is working fine now. So it has to be something in the hotend.
So it sounds like the next step is a cold pull.
Mini+ (kit) - Revo Micro | Antler Cooling | WiFi (4.4.0RC1)
RE: No extrusion on print
I did the cold pull process. It was kind of a PITA at first and I almost got a full blockage situation, but was able to heat things up and shove the broken bit through.
At 270, the plastic flowed easily, but I did note a couple of blobs in the first two pulls. At 90 it was just stuck, I pulled at 95-100. In any case, I did three pulls and things look good.
Printer is currently laying down a beautiful first layer and no noise at all from the extruder. I'll call this a success. 🙂
Mini+ (kit) - Revo Micro | Antler Cooling | WiFi (4.4.0RC1)