White spots on print, appearing over Time
Hello,
I wanted to try the new Sunlu PLA Meta (grey) for precise prints using a 0.25mm nozzle at 0.1mm layer height. While the initial results were satisfactory, I noticed that after 1-2 weeks, some parts especially the older ones (I had cut the object for easier printing, see older photos) started showing white spots in certain areas (see overall print, bottom print, and prow close-up). I am pretty sure they weren't there when I first printed them. Also, some parts of the print, like the back and top, remain completely clean, so I don’t think it’s a storage issue. It also likely isn’t due to light exposure, as the bottom part despite being the least exposed shows the most white spots.
I looked online for a solution, and the only similar issue I found was with white spots appearing on the first layer. However, that doesn’t seem to apply here, as parts on the topmost layer are also showing white spots (see Picture 2), so I’m unsure if it’s related. I’ve never encountered this issue before, but I may be overlooking something.
Before this, I printed a few benchys, including one with the same settings, and none of them have these white marks (see Picture 3).
When I apply a bit of alcohol to the white spots, they disappear briefly but reappear after 10-20 seconds.
Has anyone experienced this before? Is there a way to fix or prevent it?
Thank you in advance, and apologies if the answer is obvious.
Prusa MK4 in an enclosure, with PEI sheet, firmware 6.1.3, and PrusaSlicer 2.8.1.Enclosure includes a fan.
Photos
Overall_print
Bottom_print
Prow_close up
Older-photos
Benchy
Prusaslicer
