Horizontal surface patterns / uneven layers
I'm getting strange artifacts / patterns on horizontal surfaces / layers. I reached out to Prusa support. One guy said it was nozzle wear which I wasn't buying much since I only run the printer since june when I built the kit and I only print occasionally. I tried a test print with the 0.6 CHT nozzle with similar results.
Another support guy suggested I try to adjust belt tension. I had bad / mixed results with the tuning app from my kit build, but I thought I'd give that another try. The belt tuning app was giving me a hard time and wasn't very consistent, but I think I finally worked out how to use it to get some actual results that seemed to make sense. So I retentioned both X and Y belts. After that I did some more test prints (see smaller, transparent test prints at the end - single layer for the black ones, 2 layers for the yellow filament) and I don't think the problem was solved.
I normally print with the stock 0.4 CHT nozzle that came with the kit.
At first I suspected (cold) air draft, but later scrapped that theory. My printer sits in a nook in a wall that's shielded from draft and the issue manifested every time regardless of temperature / ventilation in the flat.
The prints in the photos were all done with PLA using unaltered Prusaslicer profiles.
I'd appreciate any hints, thanx.
After belt tensioning:
(single layer)
(2 layers)
Best Answer by Mike B:
The single layer prints are interesting. From the photos it appears that anywhere the print speed is higher (i.e. in the interior) there is extreme under-extrusion.
I'd start with looking at the other tabs in PrusaSlicer - Print Settings and Printers. Look for changes from the defaults.
Perhaps it's something to do with the extruder not being able to pull the filament properly? Check the idler screws - maybe tighten them slightly? Is there resistance in the filament path?
If you want someone to help with checking the PS settings, gzip up the 3mf and post it here.
RE: Horizontal surface patterns / uneven layers
Also not sure if that's related, but I noticed this behavior close to the edges of the print (more filament seems to be deposited near the edges).
RE:
Btw just for the record I store my filament in the ziplock bags I bought them in with dessicant bags. I don't leave the spools laying around after printing and always put them back in the bags. I think the issues I'm seeing are not related to filament quality since the patterns are consistent across different filaments.
Btw the patterns seem to "stretch" along the X axis.
Also for the record I mostly use the PEI print sheet or the textured one. I clean every time before and after prints with IPA and wipe with a cotton cloth.
RE: Horizontal surface patterns / uneven layers
The single layer prints are interesting. From the photos it appears that anywhere the print speed is higher (i.e. in the interior) there is extreme under-extrusion.
I'd start with looking at the other tabs in PrusaSlicer - Print Settings and Printers. Look for changes from the defaults.
Perhaps it's something to do with the extruder not being able to pull the filament properly? Check the idler screws - maybe tighten them slightly? Is there resistance in the filament path?
If you want someone to help with checking the PS settings, gzip up the 3mf and post it here.
Prusa MK4 since Jan 2024, Printables: @MikeB_1505898
Before doing anything drastic do a cold-pull, it isn't likely but it might fix the problem quickly and easily.
...and lay a straightedge across the print sheet, perhaps shine a light on the back of it - and check for gaps indicating a non-flat bed.
Cheerio,
RE: Horizontal surface patterns / uneven layers
I did try a cold pull actually so I don't think that's an issue.
RE:
Try a manual Z-layer calibration: The automatic procedure bangs the printbed into the stops at the bottom but they aren't very consistent. Manual results are much more accurate. In theory, the error is always compensated in software but there may be a permanent tilt of the printbed between the three Z-axis screws:
- get a business card or similar piece of cardboard as "feeler gauge" and run the printbed up to Z=0
- move printhead next to one Z-axis spindle. Inserting the card between nozzle and printbed, manually turn the stepper to exactly close the gap.
- move printhead carefully (!) to the 2nd Z-axis spindle. Adjust with the card
- repeat for third spindle
- iterate until distance is everywhere as consistent as you can get it, within one stepper "click"
Then try printing again.
Note: Running automatic Z-axis calibration would "erase" the manual calibration as it's "stored" in the mechanical memory formed by the three spindles (the printer cannot control spindles individually).
RE:
^^ please disregard above - this is about MK4, my reply is for Core One.
RE: Horizontal surface patterns / uneven layers
I looked at https://help.prusa3d.com/article/idler-screw-tension_177367 and adjusted the screws accordingly and I think it definitely improved things.
I'd say it's not yet perfect, but much better.
I wonder why tech support didn't even mention that in like 5 different sessions.
Thanx for the tip!
The single layer prints are interesting. From the photos it appears that anywhere the print speed is higher (i.e. in the interior) there is extreme under-extrusion.
I'd start with looking at the other tabs in PrusaSlicer - Print Settings and Printers. Look for changes from the defaults.
Perhaps it's something to do with the extruder not being able to pull the filament properly? Check the idler screws - maybe tighten them slightly? Is there resistance in the filament path?
If you want someone to help with checking the PS settings, gzip up the 3mf and post it here.