Multicolor bleeding - how can I fix this?
Hi fellow Prusa owners,
I have a problem with the MMU2S which really annoys me. I get color bleeding in the first layer as seen on the picture. Some sort of black string is mixing through the white. The things I have tried:
- Increase purge block. This seems not to work.
- Print without a brim.
- Cleaning the nozzle ( I might think changing the nozzle might work).
- Change the layer height
- I also tried different materials but I am getting the problem over again.
- There are NO strings, I multiple check on them
Does anybody of you have any suggestions?
from my point of view, the color bleeding might be due to a partial melting of the previous component at the border regions that contact directly with the fresh extruded hot filament.
One more reason could be, that not only the temperature plays a role, but also the compatibility of the filaments at the border region. So, maybe the transparent is a kind of disolving the black one, when he contacts it at processing temperature. Do you see the same phenomena when combining other pairs of different fillaments?
By the way, I like your prints! 🙂
You might not be noticing the stringing, but I can't see what else it is. The string it too long, too consistent, and doesn't follow the print paths for it to be a purge issue. Either it is strings coming from the nozzle or the plate wasn't cleaned before printing and they were already on the plate.
I just dealt with some weird stringing issues myself. I couldn't see it with other colors I was using, but after running a bunch of white through I could clearly see that the filament was leaking out between the block and nozzle. When I went to remove the nozzle I found it was so loose I could have removed it with my fingers (except for the 275 degree issue...). Put a new nozzle in, properly tightened it, and now it's back to nice clean prints again.