Bumpy print walls

I’m seeing strange bumps in walls, with brand new SM filament. This was printed with the SM Normal profile:

What’s with all the bumps?

Overextrusion? Maybe I need to (re) run the extruder calibration?

Looks to me like Cura’s “fuzzy skin” mode. Do you use cura and possibly have that setting on by mistake?

If not I would suggest that it looks like over extrusion or a partial nozzle blockage. Have you calibrated for you filament diameter? Most slicers will just assume its 1.75mm nomial diameter but if yours is significantly larger you will get fairly significant over extrusion

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Huh - neat. I hadn’t seen fuzzy skin mode, and no, it’s not turned on. This is a fresh install of Cura, so I’d be surprised if an experimental feature was turned on by default.

I haven’t calibrated the filament diameter, will look into that, thanks.

I actually just replaced the hot end, so I’m going to look into partial blockage as the second possibility.

Thanks for the ideas!

The filament is wet.

Partial clog possible too

Brand new filaments can still be wet even if sealed

Also, snapmaker filament is not great quality.

Try to read how to bake your spool, swap your nozzle and try again, it will be night and day.

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So far “wet filament” is the leading candidate.

I swapped out to some white HatchBox I had and it’s much improved. I will try baking the filament and see if I can get it even more dried out. Thanks!

Disappointing that SM filament, straight out of the sealed package, was wet. /shrug

ill be honest, snapmaker filament is meh, with the exception of what was shipping in the box with the machine, which was utter garbage

however, i often times open brand new spools and they are wet. even sometimes on the good brand stuff.

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I guess a bit overextrusion, try to print not with 100% infill, take 80% for a try.
My first guess was, printed too hot. - Did you print a temp tower?

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Ok, I just ran the e-steps calibration and oh my god, I’m 99% sure that was it.

My E-value was like 345, and the first time I ran the test, it extruded 140mm instead of 100.

After a few iterations, the dialed-in value was 233.33, so yeah, extruding 40% more material than desired could generously be called “overextrusion”. :slight_smile:

BTW, I think what happened is that I ran into all kinds of problems with the original hot end, which I now think was fairly well blocked. I had run the extruder calibration with that, not knowing it was blocked, so yes, the crazy-high E-step value was probably reasonably correct…for a mostly-clogged nozzle. When I replaced it with a brand new hot end, I was suddenly pushing way too much filament.

So the reminder to self and other newbies is - when you swap in a new hot end, you should at least re-run the extruder calibration and re-level the bed. I wonder if any of the pros have other suggestions.

Running bed calibration now, and working on slicer flow calibration, but I think we’re over the hump for the most part. Hearts for everyone in the thread!

Here’s the slicer flow calibration cube. I thought we all deserved an “After” picture. Smooth as silk.