Not sure if anyone has seen this before but I bought two spools of PETG from Elegoo, one in white and one in black. Their regular PETG, not the rapid one.
Yesterday I printed with the white spool and it worked pretty well.
Today I tried to print with the black spool and the filament would not come out of the nozzle. I tried diagnosing the problem and ended up swapping nozzles, taking apart the nextruder and putting it back together. Then I tried printing again and again the filament would not come out. I swapped back to the white filament because at this point I’ve essentially ruled everything out except the filament and the white filament worked. I then tried the black again and it would not print. I cut off about 10cm of the filament and tried again and same issue. Finally I cut off about another 50cm and now it started to print.
I’m not sure if this has happened to anyone else or if anyone knows what the issue is. It’s almost as if the filament refused to melt or had an much higher melting point vs the rest of the spool.
If you still have the length of filament you cut off, you can verify your temperature theory pretty easily by loading it up temporarily and trying increasing nozzle temperatures until you get it to extrude. That spool of filament may have been contaminated by having a couple of pellets of the wrong stuff in it. Plain PET (rather than PETG) is most likely, I think, and that stuff won’t extrude until you wind your nozzle up to probably about 240° C.
It might have been a diameter issue as well, but I’d doubt it. My printer’s drive gears can still grab objects that are quite a bit smaller than the prescribed 1.75mm filament diameter, and if the stuff were so thin or thick it wouldn’t feed I think it’d be quite obvious to the naked eye. I imagine this is the case with pretty much any modern printer.