EDIT: GREAT DIAGNOSTIC SUGGESTIONS + SOLUTION IN COMMENT STREAM
Hopefully this is a quick one:
With one PLA roll, a particular print jams the extruder at roughly the same point each attempt. With a different PLA roll (different brand), the jam doesn’t occur.
Is there a most likely cause? I’ve seen multiple possible causes for an extruder jam: clogged gear, loose gear, bad calibration etc. In this case, though, switching plastics seems to fix it, so is there any “most-likely” cause and resulting way I could compensate for the difference in plastics?
Same print temp for both rolls? The one that clogs might be a bit too hot, softening the filament before it gets into the heat break tube. Causes a mushroom head shape, you can see this when you pull out the jam.
@Geoffrey_Forest Thanks! Same temp. I’ll check for that mushroom head. BUT…
I just confirmed that my "good’ PLA also jammed, but at a later point. I’m starting to think it’s this print or a machine issue, and that different PLAs just manifest it differently. Just had a good print a couple days ago BUT there seemed to be a lot of isolated delamination between layers. Maybe that’s related?
Hotend fan working correctly?
I’d say you need to lower the temp or add more cooling for extruder. Probably pla is softening at wrong position.
Make sure filamen diameter is correct too, i have no problem with clogging after measure each filament before i using it, put the diameter value in slicer
Sounds like a heat creep problem. As mentioned before check your cooling fan or try a slightly lower temperature.
If there is a PTFE sleeve in your extruder you should check that it is not worn out or damaged from heat creep. Once damaged the tubes will start to swell when they get “cooked” and over time on a print will choke it off and trigger a jam.
Last, and this may sound counter intuitive, you can increase your print speed so long as you don’t trigger a skip or a grind. Keeps the heated filament zone smaller.
Ditto what @Topias_Korpi said. Sounds like your heat break tube is slowly getting too hot during a print and is eventually softening the PLA too high up. Lower temps or better fan.
The hotend fan seems to be working. I’m going to try to print another design to make sure it isn’t just this print. Is it possible that narrow pieces would cause this to occur or contribute to the condition?
I’ll try lowering the temperature after this test to see if it affects the outcome.
This sounds to me like the first roll is out of tolerance and/or made with substandard PLA.
Thanks all for the input. Quick Update.
I think that Brent and others are right, and I was using two different qualities of PLA, but that it was basically just exacerbating the real issue. However, I have made the mistake of changing two things at once. I both tightened the pluger down to hold the PLA tighter against the drive (since I was able to stop it with my fingers easily), and changed my print to not use a raft, which I realized was probably not necessary. I also tried an older known good print file and saw improvements in the print quality after the plunger adjustment.
Now the print is going pretty smoothly with the known good PLA. I’ll try the questionable PLA next but for now it seems like the plunger adjustment has helped.
Ahhhhh, interesting! Good on you for nailing down your debugging process.