Weird pattern on surface - extrusion issues?
Hi,
Long time printer here, got the MK4S to Core One upgrade kit in June and have been enjoying it since. However, the last few weeks or so I've been seeing this weird texture on prints and wow am I struggling to figure it out. I've tried different nozzles, taken the extruder fully apart and clean/relubed the gears (and then recalibrated...) etc. and... it's always there. Tried loosening the idler springs... tried tightening them, no changes. Any ideas on what it may be or how to narrow it down?
RE:
(I'm "extrapolating" as I haven't seen this pattern myself yet)
Do you manually calibrate the print bed angle or do you rely on auto Z-axis calibration? If the latter, it is quite imprecise (people are 3D-printing shims as an improvement but it's nowhere near what can be achieved by manual adjustment, +/- 1/2 stepper click).
Take a business card or other thin piece of cardboard. Run the table to the nozzle with the card in between, then very carefully move the printhead around and confirm that the gap to the bed is equal everywhere. If not, turn Z axis screws manually until the cardboard fits equally tight anywhere on the printbed (running a Z axis calibration afterwards will undo the manual adjustment).
Hypothesis: The printer's own Z calibration (via the load cell sensor at print start) is "almost" perfect. Which may be not good enough here - generally, it seems preferable to eliminate mechanical error at the source than to compensate in software.
edit: you're asking about the Moiré-like pattern, correct? Not the occasional blob?
RE:
If it's the surface moire pattern, I had something similar that went away after I fixed the belt tension that was way off. If the belts are OK, try reducing the print speed. Also, what kind of filament is this? I had the issue, in particular, with Silk PLA.
- Bob Marley
RE:
Yes, it's the surface pattern - apologies on not being clearer. 🙂 Thanks all for the suggestions. Just got finished chatting with support and best guess at this point is failing extruder motor. It's making some weird clicking noises (albeit they are very faint) when spinning all by itself so maybe a bearing or something? would def make sense because each line of extrusion is wavy - if you drag your fingernail against the outside perimeters it'll kinda "buzz" due to the waves. Crossing fingers that'll do it, they're shipping one out so I'll update when I get it put in.
Thanks again!
To quickly answer some of the questions - bed is leveled via the mod to measure and then print different height "stops" for each of the 3 motors. that got me to darn near perfectly level.
Happens on any/all filament, PLA, PC CF, PETG etc. Both third party (Atomic Filament, Polymaker) and Prusament PLA/PETG.
Support had me print one of the demo gcode files (decided on the keychain...) to rule out slicer issue. (no change in results btw)