Banding caused by differences in layer time

nicholasivorjohn · July 31, 2023, 2:27pm

I’ve noticed that I get slight banding when printing on the X1C when the layer times between layers are significantly different.

I mainly print PLA+ from Sunlu in black colour.

Initially I thought it was the difference in speed that caused this, but upon removing the option to slow down for the layer made it worse. Slowing down the print turns matte zones very shiny and is undesirable.

But when looking in the slicer the bands on the print perfectly correspond to the banding shown in the slicer preview for layer time.

For my particular filament and after many tests I came to the conclusion that any layer that took less than 15 seconds would have visible banding compared to layers that took longer.

So I tried tweaking my print settings for those faster layers to make the layer print a bit slower. I decreased the infill print speed so that it was essentially crawling along, and this helped massively. Were I tweaked these settings the banding went away completely.

I also found that tweaking the speed can help as long as you dont go to slow. Anything slower than 150mm/s and the prints become shiny again.

So with a combination of the 2 you can eliminate the banding but my oh my is it a manual process.

It would be much better if in the layer change section if we could say “if layer_time < 15 seconds then dwell for 15 - layer_time then print a prime tower” but sadly the layer_time parameter doesnt exist or at least is not accessible to us.

Something similar to this exists in Cura where it can move away from the print. This can cause oozing but this can be dealt with by using a prime tower which would only take a few grams of filament.

For those interested here are my settings:

Temp: 220
Part fan cooling: 100%
Aux Fan: 70%
Filament: Sunlu PLA+ Black
Dont slow down for minimum layer time

Default X1C print settings

Ive opened an issue on github: Move away from Print when Layer time is less than X · Issue #2126 · bambulab/BambuStudio · GitHub

If anyone has any other ideas how to mitigate this please share them.

lkraus · July 31, 2023, 5:51pm

The filament cooling settings do allow setting a minimum time per layer. I’ve not had your problem or had a need to change the default settings, but it might slow down your print without needing to change individual speed settings.

nicholasivorjohn · July 31, 2023, 6:20pm

This slows down the print though, and slowing down the print below a certain amount has undesirable effects. When you slow the print it becomes more shiny, thus compounding this issue.

Sapper4484 · September 14, 2023, 8:56pm

Glad I found your post. I’ve just got an X1C and very pleased until i came across the same issue for a specific print, it was by chance I was looking through the various options in the slicer and saw the layer time looking exactly like the bands i could see on the print t. I’m printing a Bambu Silver cylinder with some detail on the inside that causes regular slow downs of the layer and in my case its not just visual there are minor differences in the diameter. e.g. fingernail test. Which having been down the rabbit hole I surmise this could be due to minor differences in shrinkage. Testing has shown the same issue on the same part but less obvious with a Matt Bambu filament. My first search led me here and i see there has been a lot of conversation on github which i will follow from now on and. Ill be trying some of the suggestions to see if i can reduce the effect. Its for a model so im not that bothered if i cant get it perfect but i like to understand why things happen for future prints.