PETG extruding VERY slowly
I was having trouble printing PETG after printing 6 successful prints using the same filament and settings. Out of the blue the extrusion process seems to have slowed way down and nothing is printing correctly.
So I decided to do a 1st level calibration. My idea was that this would take the slicer settings out of the equation. The printhead went through its dance and extruded a normal line up and started slowing down on the back stroke and then went to a crawl for the calibration until I stopped it. I could watch through the hole in the side of the extruder. The gears turned at normal speed while advancing the filament for the first part of the initial purge pass and then started slowing down to almost not even turning.
Then I tried a first level calibration with PLA and that laid down a nice pattern and showed my setting was correct.
Strange as it might sound it is like the printer thinks that PETG is TPU now.
Thank you for any help. I can manually extrude filament by doing a preheat and just pushing filament through with the gripper spring released. So the nozzle and heating seems fine to me.
Bob
RE: PETG extruding VERY slowly
The hole on the right side of the extruder? The gear you see there isn't driven by the motor, it is driven by the filament being pressed up against it. It doesn't turn if the filament isn't moving.
The first and easiest thing to do is try a cold pull. https://all3dp.com/2/3d-printer-clogged-nozzle-how-to-perform-a-cold-atomic-pull/
If that doesn't resolve it, disassemble the extruder and make sure everything is clean and well put together. There's an axle on the idler door (see below) that worked its way out on my printer. This caused all sorts of problems. One of the things it might cause is no extrusion. This axle holds the gear that I think you were looking at. If it came out, then the filament might not be gripped tightly enough for proper extrusion.
With the extruder disassembled, check the PTFE tubing below the gears. Make sure it is round and not clogged. Replace it if necessary, I think your printer should have come with a spare or two. Clean off the gears so that there isn't any ground up filaments or stringy bits on them.
RE: PETG extruding VERY slowly
Yes, I was looking through that hole. OK. that makes sense that it must be slow filament movement. Interesting in that I can print PLA for hours with no problem.
I have partially disassembled things and there is/was no trash in the gears or the paths.
Thanks for the reply.
One thing I thought about is the filament not melting properly, but it seems very strange because if I do a preheat and let the nozzle get to temp I can push filament through with my fingers and it extrudes a nice strand. The harder I push the faster the filament comes out.
I have been out of town and will resume this week with my investigations. I plan to try other PETG filaments and see if perhaps it is just this spot in the one reel. It printed from that real for about 5 hours worth of prints before this failure. The interesting this is that in between those 5 hours and the failure I printed a small TPU project. It is a steel .6mm nozzle and I actually took it out and burned off the filament with a torch because I suspected a clogged nozzle. I could see clear through the nozzle and it prints PLA fine.
RE: PETG extruding VERY slowly
Looks like it is a bed adhesion problem. I realized that I used the smooth sheet before I got the textured one. Tried it and ran the first layer calibration with PETG and it ran just fine. The filament extruded very slowly and laid down just fine. This has greatly increased my understanding of things.
Now I just need to find out why the textured sheet NO LONGER works. I printed a 6 prints on the textured sheet and then one TPU. That was the last thing that printed on the textured sheet. I have scrubbed the sheet with soap and water (a method that never failed me before) and scrubbed it with IPA to no avail.
I read some people sand it lightly or use fine steel wool. Not sure I want to try those, but what's to lose if it won't work as it is?
Thanks for the help.