Hello,
I’m running into an issue with my X1 Carbon and Multicolor prints, specifically around layers “bleeding” or dragging “trash/bits of filament” into one another. I am attaching a few pictures where I am circling the issue that is occurring. I have made several adjustments in Bambu Slicer to try to fix it, but I am a newbie, so not sure if what I am setting is helping or hurting. I am also attaching my slicer settings below too.
The main issue I am trying to troubleshoot is when a layer ( lets say the black logo in the screenshots below ) is done printing, can the X1 carbon essentially stop flowing filament/material as it travels over the white layers? I realize that white to black transitions are difficult with Multicolor, I have increased my purge between layers to try to fix it, no dice.
To me it seems like when the black logo in layer ( layer 1 ) is done printing its dragging bits of filament onto and over top of the white layer 1. Then when layer 2 white starts printing its embedding the black onto the white ( hope that description makes sense ). I have timelapse video of the print if it helps, can upload.
Specifics about the machine/print and slicer settings are below:
Printer: X1 Carbon
Printer Firmware: 01.06.05.01
AMS Hub Version: 00.00.00.42
AMS 1 Version: 00.00.06.40
AMS 2 Version: 00.00.06.40
Printing with only Bambu Lab PLA Filament ( Black and White in this example ).
No 3rd party Filament is being used.
Humidity in the AMS is ~35% at time of printing.
Printing on a Textured PEI Plate ( Bambu Labs Textured PEI Plate )
The design was done in Fusion360, each part of the Logo was set up as a different Component, don’t believe anything would matter in the actual Fusion design though…
Component 1 ( Base ) was set to 2.6mm
Component 2 ( Logo ) was set to .4mm
Component 3 ( Top level Infill color ) was set to .4mm
Just looking for anything I can do in the Slicer to help clean this up. Any help would be much appreciated!!!
Thanks!
Alex
If you own a filament dryer, try drying your filament. If you don’t own one, I recommend you get one and try drying your filament. Stringing and oozing happen because of moisture in the extruder being heated to steam (too high an extrusion temp can also contribute but that doesn’t appear to be an issue in this case).
You could look at changing the order things are printed, doing the white first. Though that might result in white stringing in to the black, it’d be maybe worth a shot.
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Seeing what you are doing, it does look to me like you are aiming for perfection above an already pretty good piece 
It’ll be tricky to get better though.
- Reducing speed, acceleration, jerk is a common recommendation to improve quality. It looks like you are at the maximum.
- I have found arachne not so good for very thin lines. I did observe increased blobs with that sometimes.
- I think you may need to actually set a value in order for the “Avoid crossing walls” tick to have an effect.
- Think about surface and infill patterns that minimize crossings and rapid changes (i.e contentric surfaces and gyroid or honeycomb infill for thicker parts)
- Tbh, I am not sure if it will actually help so much, but you may want to think about increased z-hops (with coasting)
Hope some of this may help. But I think you are actually doing pretty well already 
Are you using the black PEI plate? I got similar artifacts printing a single color (orange) after printing black parts. So it may have been still stuck to the nozzle or ingrained in the textured plate, I’m not really sure. ABS does stick really well to the PEI with glue so I think I’ll use the gold one going forward as it will be much easier to spot.
Also ensure that the filament settings are correct. Use component cooling. Calibrate the filament carefully. The automatic calibration only works for one filament at the start of printing. Calibrate both filaments to obtain the correct K value for both filaments and make sure that the K values are also visible and set in the AMS view during printing. Then omit the automatic calibration at the start of printing. Make sure that the nozzle is clean before printing and that the wiper mechanism in the printer is clean. Remove filament residues from the printer before printing if filaments have collected on the wiper. Do not print too hot, but as cool as possible and as hot as necessary.
@RocketSled already mentioned drying.
This does not look like actual bleeding, as in not purging enough, more like your filament is stringing and that is being embedded in the print. Have to you tried printing a stringing test and compare it to your temperature/retraction settings?
I re-read your post and I’m not seeing any mention of drying. The only thing I see is AMS@35%. The AMS doesn’t dry filament, though. It doesn’t even keep filament dry. It just slows down how quickly filament absorbs moisture before it needs to be dried again. So the AMS with a reported 35% RH does not mean the filament is dry.
Also, the humidity value is “Relative Humidity”. Temperature matters. Higher temperature air can hold more moisture. So for the exact same moisture content, the air’s RH will go down as temperature goes up. Which means the moisture content of the filament could be higher, even though the RH is lower, because the temperature went up.
The AMS should really report “Absolute Humidity” IMO. It’s just a slightly different equation for the same sensor.
I print a lot of Nylon. Right out of my filament dryer (24 hours at 70ºC), it prints about as nicely as PLA does. After a week in the AMS (yes, with good desiccant) it will start to ooze and blob a little. Nylon can absorb its fill of moisture in just a few hours, the AMS slows that down to about a week, it doesn’t stop it completely.
Oozing/stringing really has only two causes - moisture in the filament or much too high an extrusion temp. Drying is a relatively easy thing to try to see if it makes a difference, too. Much less work than all the other suggestions you and others have made. Give it a shot, you might be surprised.
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Its this problem solved yet? because i see no solution here. I dry all my filament before use, and still facing the same issue, i saw their commercial printed without issue. Btw i slow down the print to 50% from the default. still same.
Some problems are solved, but nothing is marked as a solution.
You will always have problems here and there, there is no other way when you print colours in one another. You can only minimise problems, for example by using high flushing volumes and/or a wipe tower. Sometimes filaments mix because residues of one filament remain in the nozzle, which are then gradually flushed out with the next filament. Filament with too high a moisture content also tends to stick to the nozzle.
Some filaments allow colours behind them to show through, such as white. Here you would need to use more walls for printing.
Mixing can always occur, especially in the border areas between two colours of a model. While one wall is printed in black, the adjacent wall is printed in white. However, both walls are fused together, otherwise the parts would fall apart. If the hot nozzle loosens the black filament to join the white wall to it, the black filament may be released, which is then reflected in the adjacent white wall. However, if particles stick to the nozzle, they can also be deposited elsewhere in the white area of the model because they only detach from the nozzle later. It might also help to increase the number of walls on the model where colour mixtures are particularly noticeable. However, a higher number of walls would not help with surfaces.
Best regards
Got it. Appreciate the explanation and thanks for helping! 
