Comment on Weird Underextrusion
beeb@lemm.ee 7 months ago
All seems to indicate something related to pressure advance, whereby the printer thinks it needs to extrude less because of some pressure buildup but it underestimates how much is really needed. Does it happen if you print slowly? E.g max 20 mm/s or so.
I’m printing ASA at 30/50mm/s right now, and I’ve halved the pressure advance value without any noticeable change. I agree with looks like pressure advance, though. I’ll try a really slow print soon and see if that matters.
Printing PLA at 120mm/s had it show very lightly, but it’s still there.
wccrawford@lemmy.world 7 months ago
At 15mm/s, it looks like the underextrusion is about half the size.
imgur.com/a/F0sXBvJ
beeb@lemm.ee 7 months ago
Interesting, that would confirm the pressure advance as the likely culprit. Maybe your slicer has a bug related to this? If changing the value wildly does not improve or worsen it, then it might not be calculating what it’s supposed to. Can you try another slicer?
wccrawford@lemmy.world 7 months ago
I used an older Cura that I already had installed (instead of Orca 2 that I’ve been using) and the underextrusion pattern is different, but still there.
IMALlama@lemmy.world 7 months ago
If you’re slowing down significantly and seeing an improvement, I wonder if it’s an adhesion issue vs an extrusion issue. It is very weird that it’s so localized though. I almost wonder if the nozzle might be influencing things somehow. Is it clean? Get it up to temp and give it a wipe with a folded over paper towel.
wccrawford@lemmy.world 7 months ago
I’ve cleaned the bed and not applied 3DLAC, and it hasn’t helped.
IMALlama@lemmy.world 7 months ago
That’s disappointing. I’m sorry to say, but I’m out of ideas. Maybe try the Voron design forums since they have more active users?
wccrawford@lemmy.world 7 months ago
I tried a never-used nozzle with no difference.
The bed hasn’t been cleaned in a while, but the parts that aren’t underextruded stick very hard. And it happens the same in every place on the bed (I’ve tried about 8 now, always with the same pattern) and 2 different beds.
I’m still thinking it’s a pressure issue, where it initially doesn’t have enough pressure for some reason. But I turned up the KAMP purge flow and it made no difference, and extruding 2 skirt lines made no difference that I could tell.
My next step is going to give the bed a good cleaning… And even try the other side that I’m pretty sure I’ve never used yet.