They happen when lines meet where the width of the feature isn’t an exact multiple of the extruder’s width and the printer has trouble filling in the void. Usually they’re fairly invisible, but when printing white on black, they stand out like a sore thumb.
I’m wondering if there’s a good simple way of avoid this problem in the slicer. The ultimate fix of course is to print a square sheet of white PLA under the white letter, but I’d rather not mess with my model because it’s quite complex already.
Yes I do use arachne. I did try to change it to classic when I was messing with my 3D-printed lens experiment, and while arachne wasn’t perfect, it left fewer artifacts inside the “lens” than classic.
I’ll try to revisit classic for this one print.
I’ll try ironing, This one is purely an esthetic problem. The part is just a cover for a case that holds electronic bits inside.