I'm printing those little cable pull tabs on our Prusa XL printer. In the models, I added markings to identify the type of cable, printed directly into the tabs with a different color PLA loaded on head #2.
The problem I have, as you can see, is that the white letters are "overrun" by the back surroundings.
I have to print those parts face down: when the first layer is laid down onto the bed, the black surrounding is printed first with head #1, leaving empty space for the symbols, then head #2 comes in and fill in the spaces after the head change:
The problem apparently is that the black material gets "smooshed out" on the bed and partly fills in the void, and then the white PLA doesn't have enough space to make nice, sharp letters.
It wouldn't be a big problem with larger letters: they would just look like they have fuzzy edges. But those letters are 3.5mm in height and only two 0.4mm-wide lines at the most, so it's basically all fuzziness.
It doesn't happen when I print face up. But then I have to have support for the tabs' walls, and since I print those things by the hundreds, I'm really not keep on having to remove support on hundreds of tiny parts. So it's not an option.
I tried printing slower but it doesn't change much of anything. Not to mention, again, I have to print those things as fast as possible to print as many as possible overnight.
And of course I can't increase the size of the letters: they're as big as the tabs' size will allow.
The letters are readable enough, but they don't really look great. Is there any trick to reduce or eliminate this? I was thinking of trying to print the white first with head #2, then the black with head #1, but I can't find an option in Prusa Slicer to invert the order in which the heads are used.