I posted here the other day and got no replies so I guess it was too long of a post. So, I’ll keep this one short.
If I print with more than 2 walls, such as 4-5 walls, even with he default “0.20mm Strength” profile, I get z-banding.
It seems like any layer with a higher “layer time” is prone to banding.
My question to anyone who prints with 4-5 walls, if anyone could please share: do you print with 4-5 walls, with PLA? And if so, what settings did you have to change to avoid z-banding?
Thanks!
Show pictures of a “good” and “bad” example.
I print functional parts, mostly, and use high wall counts all the time. In fact, I often use high wall count in place of concentric infill. Haven’t noticed any issues related to wall count.
I do not, however, print PLA.
maybe post a picture of what you are calling z banding, generally with a 0.40 nozzle with 4 wall thickness the walls would be 1.6 mm thick and the speed that you print your outer walls should normally be slower than the speed you print your inner walls and the order that you print your walls in makes a difference in the look of your outside walls also the infill overlap will sometimes show on the outside walls if that is set to high. and the extrusion multiplier also known as wall flow in some slicers can make a difference on over all appearance because when it is to high with just 2 walls it doesn’t show up as much but when the wall are multiplied then the over extrusion starts showing up more obvious . so maybe some calibrations may be needed but pictures would help determine that.
Thanks for the replies, I appreciate any help I can get!
The following are photos of the banding. The higher layer times still exist when I print with 2 walls, but the banding no longer shows. The following prints were all done with 4-5 layers.
And here’s a photo of the higher “layer time” layers that correlate with the banding (you can see the layers that print faster give the appearance of over-extrusion or the slower layers with under-extrusion):
Add one picture of a “good” one. 
And the slicer screen grab for that one as well.
Thanks! I forgot to share one for that.
Here’s an example of the same part printed with 2 walls. You can still see the banding ever so slightly, but it’ll easily disappear with painting. (ignore the sloppy overhangs, this was printed with all PLA vs my clean overhangs which I print with PETG as the interface layers):
And the sliced object (this is a part for a cosplay Star Wars blaster prop, but it doesn’t matter what object I print, if it has support of any material it will have banding with 3+ walls):
Edit: also, FWIW, I would happily print any object (that includes supports and is a reasonable size) with any settings, multiple times, for comparison, if it might help us figure out the issue.
Wow. That is a huge difference.
Something weird.
High Wall count slice shows the fastest layer is 68.7 seconds.
Low wall count slice shows the fastest layer is 0.7 seconds.
The low wall count slice is clearly wrong. No way those are accurate layer times.
Maybe a slicer bug here?
The fastest layer count being 0.7s seems weird to me too. I just checked, since you pointed it out, and I found a couple layers have barely anything on them (one example being 3.8s, for a support layer). So that tracks I guess.
The print with a min layer time of 68s was a print for 2 items, and had some other settings added as well. I took that screenshot the other day. Sorry for the confusion!
To eliminate the layer time discrepancies, here’s a single screenshot. The difference in the layer time comes from one being printed with all PLA, and the other being printed with PETG as the support interface but the rest is PLA. These are both layer times for 5 walls, with all default settings from the “0.16mm Optimal” profile:
EDIT: It’s possibly worth noting… the one thing that’s ever made a difference for me, while still printing with 5 walls, is changing the print order to outer/inner/infill. That got me an acceptable print with 5 walls. It still had banding but it was very very minor.
Ah. PLA w/ PETG supports is an additional key detail.
Look carefully, are the layers with the worst extrusion also layers where a support interface was printed?
Your problem may be insufficient purge.
I can tell you right now, because I realized/confirmed that already previously myself… yes, the banding is worse in the layers with support interfacing. I’ll have to play with the default purge values, then. Now that you mention it… on my one single print with a high wall count, that printed well, in addition to changing the wall print order to outer/inner/infill, I did also increase the PETG->PLA purge amount I think. It’s been a minute.
I’ll test that out I appreciate the advice!
PLA and PETG don’t mix, which is why they work as support interfaces for each other. So if you haven’t fully purged on a filament switch, you’re going to be printing PLA with PETG mixed in. That’s not going to flow properly whether the printer thinks it’s PETG or PLA that’s being extruded. Won’t be right for either. That’s going to result in a messy print.
Makes total sense, thanks! I got fed up previously, on my one print that finally printed ~ok~ with inner/outer/infill set, and I set the PETG->PLA purge to 999.
Currently, to eliminate PETG as a possible cause for the banding (because due to my weeks of troubleshooting I’m pretty confident it isn’t a factor although it would appear to be at face value), I did a new test print.
For this test print I printed with all PLA no PETG, with nearly all default values for the profile “0.16mm Optimal” in Studio. I did change the support spacing but printing at default 0.2mm and .5mm for the Top/Bot Z distance and Top interface spacing values still produces the z-banding.
I only changed the print speeds to match eSun’s printing parameters (but I slow down some speeds even more just to be safe): eSUN PLA+ Filament PLA Plus 3D Printer Filament PLA Pro
The banding still occurs without PETG in the mix:
Please disregard the support mess. It’s due to using PLA across all supports, interfacing, and the printed model.
This is the eSun profile I print with, which is only slightly different from the default profile due to my Bambu Studio flow calibration adjustment to a 1.029 flow ratio from the factory 0.98 ratio.
Edit: oh and disregard the purple color in Studio for my eSun PLA. I have it set to purple so I can see it a bit easier in the slicer print preview versus the actual color of gray. Thanks!
have you been able to figure this out yet? I am having huge problems when layer times slow down for a few layers due to the structure having top layers at certain heights and then continuing it creates a huge zband line.
I wish I could tell you I did figure it out, but I didn’t. The issue remains. I can do stuff like print outer/inner/infill and it helps a little. But I’ve printed as slow as 10mm/s (minus default percentages for overhangs) and the issue remains.
I appreciate everyone’s help but nobody has been able to help me resolve the issue, across Facebook, Reddit, and this forum. Everyone runs out of ideas or stops replying eventually and I don’t blame them.
I just feel like my P1S is gaslighting me. I don’t understand why everyone can print so easily but I need to change a dozen settings or more.
Edit: I’ve been planning on putting in a support ticket but I want to finish my workbench and ventilated-to-outside enclosure before I keep printing.
If the problem improves with fewer walls, it is probably also an extrusion problem. This is because changes in extrusion have a greater effect with more walls. If you have a slight over-extrusion, this is hardly noticeable with 2 walls, if you use 4 walls you will see it better. Above a certain number of walls, the problem may no longer change in terms of visibility. A flow ratio of 1.029 is definitely too much. The K-factor also has an effect. In some experiments I have learned that the K-factor is not unimportant. Depending on the filament and its properties (e.g. moisture content), a slight deviation (e.g. 0.00…) in the K-factor can show up in the print image. I can only report on practical experience in case anyone thinks that this should not be the case in theory. It is therefore important that you set the filament parameters correctly.
create a profile for your filament by first selecting a generic profile for your filament material and saving it under a different name
enter the print temperature and the temperature range at which the print will be performed
first leave the flow ratio at the default value (0.98 for example, which is pre-entered) and also the value for mm³/s
save the profile
make sure the filament is dry. PLA is easy to dry, do this as a precaution if you are unsure
Calibrate the K value for your filament with the profile you have created using manual calibration
Save the K-value for your filament
If you change the above values, flow rate (mm³/s), flow ratio and temperature or if your filament has not been dried for a long time, then recalibrate the K-value.
Another note: if you use the automatic calibration for the flow ratio, you may get incorrect values. I have experienced this myself with black PETG. I also got a value of 1.026 or similar, which was far too much, I noticed this in the accuracy of fit of the parts that I had previously printed in PLA and everything was right there.
Have a nice day!
Thanks so much for the detailed reply! I’m afraid I already tried everything you mentioned, but I might not have tried it in that exact order. I’ve been looking forward to doing exactly what you said and seeing if that fixes the issue.
I’m building a ventilated enclosure because I print in an apartment and I can’t always leave a window open, and my apartment will smell like PLA while printing and I don’t like VOCs. I plan on having it finished by next weekend so I can start troubleshooting again.
Thanks!
Set the speed for external walls to a fixed lower value, for example 65mm/s.
I have an ongoing issue on Github about something that might be related:
PLA layers squished following PETG support interface layers · Issue #2015 · bambulab/BambuStudio (github.com)
I changed my design to avoid the problem and the thread has mostly gone stale.
I think problems like this might be due to layer time differences and PLA not hardening consistently as a result. Maybe if we printed the entire model much more slowly it would look better. Maybe increasing the minimum layer time might help as well. It bothers me to think that the cooling fans aren’t enough, if this is the case. Honestly I would rather find out the problem is caused by something else and can be fixed.
Thanks for the suggestion! I’ve already tried that as well, unfortunately. I incrementally decreased the print speeds in multiple combinations. First I tried only adjusting the outer walls, then interior, then I adjusted both as well as overhang speeds.
I started with a modest speed drop to 200mm/s, then 150, and so on, down to 60mm/s, then 45mm/s, and in the end I actually just set all wall speeds to 10mm/s and dramatically dropped overhang speeds as well. For a majority of my troubleshooting, I’ve typically had inner and outer walls down to 40mm/s-60mm/s.
The crazy thing to me is: why can everyone else, except for a few of us, print multiple walls without a problem? Everyone says they have no problems printing out of the box, multiple walls, overhangs, etc, without an issue.
I’m sorry to hear you’re dealing with this too… I mean, it’s validating for me, but sucks for you…
The most common advice I’ve read is to adjust layer times so it’s all more uniform, so what you’re saying tracks.
I’ve been dreading opening a support case; all my technical intuition and experience points to my issue as being due to a user error and not a mechanical fault issue, and I’m sure support will think the same. But I’ve tried everything…
As soon as I build my ventilated enclosure, I’m going to get back to printing+troubleshooting.
Edit: btw, TechnicallyReal, have you tried adjusting the purge value for your PETG->PLA layer/s? I thought that might be a factor for my issue but adjusting the purge value didn’t help. Then I tried printing with all PLA and no PETG for support interfacing, just to eliminate PETG/PLA purge values as a factor at all, and the banding didn’t change. So I know purge values aren’t a factor for me at least.
Did you get this issue sorted. ive just hit 600 plus hours on my P1s and printed hundreds of the same peice yet all of a sudden im getting these strange z bands but not all layers it skips a few and then does it again. Im currently trying a few things out and hopefully have an answer soon.
