Hello!!
I’m a new user. I tried to print some lamps facedown but I’m having a big problem. Some dark lines or some stains in white zones. I made some retraction tests with great results. I have no idea where the problem is.
Here is my config filament and settings for 0.2mm/0.4 nozzle
Thank you very much!!!
That might be filament overheating, looks like possible burn marks?
It could also be remnants from the previous print contaminating the surface.
I havent tried this myself but what you need to do is change the colour order in your slicer.
Go to process settings:
Click on plate 1
Click on custom and drag white as the first filament in sequence
Hope it helps
My sequence is always white first, and black second in all layers… this not solve the problem 
Thanks for the answer
It seems some thread remaining of the previous layer… but I don’t know how to repair it…
Try changing retraction settings in the filament profile
Could it be stringing? If so you might need to calibrate your temps and filament retraction, especially for the darker colors, and even more so if you are not using Bambu filament.
First impression was something of retraction settings… but my test or retraction is quasi perfect!! I try with some changes of retraction… Thanks!!
Always print light colours first and black last. Lower your printing temps way down to like 208 or so for black, and enable Z-hop, and retraction. That should get you there!
Can u share your config files please?? I need to see the difference with mine.
Thanks!!
This should not be in MakerWorld as it isn’t related to the MakerWorld website. Please move this to Bambu Lab A1 Series.
Its stringing or tiny wisps of the dark filament which then get blended into the white.
Despite what many people suggest, colour order does not matter in this instance unless you’re only printing one layer thick, which I guess you are not.
Reason being is, say your first colour is white, then black the process would be:
Layer 1
prints white
changes to black
prints black
Layer 2
prints black
purges black
changes to white
prints white <— this is where the problem occurs
So you started with white on layer 1, but then switch to black and print 2 layers of black - plenty of chance for stringing and particularly small wisps or blobs of black to be created and blown around by the fan (that’s why the black can occur in pure white parts nowhere near black parts of your print).
A tiny spec of black filament sat on white parts will melt right into the white layer when the next white layer is printed. A spec of back melted in will easily show through 3-4 white layers (especially when illuminated) so it’s difficult to get a 100% clean print.
Solution
Fine tuning filament settings to reduce stringing will help.
But more importantly, you have to check the print before every white layer is about to be printed. You need to brush or blow off any little bits of black you see. You can do this quickly during the colour change process when it’s not printing, or hit pause if you need more time. It takes a bit of time, but it does produce good results.
I solve the same problem with the order color printing. It’s magic solution for me
