I believe THIS is an H2D issue with using both heads. I have a couple jobs where I use supports blending PETG with PLA and found that where there is PETG applied with one nozzle and the PLA with the other I get Z bands. At first I thought it was because of a transition between a floor and wall, but after doing a vertical job found its when ever there is PETG added to the mix. What I haven’t tried it swapping between PLA and PETG on the same head to see if it goes away, but I believe there is some issue between the two filaments and using dual nozzles, I see small strands on the purge tower of PETG.
If I use different colors PLA between the two heads, no Z band issues, clean transition between heads, its only when using PETG as the layer between support and product.
One other issue I have is that it does not provide support if there are 3 levels in the same section, only the first level was supported. Example is the Frame for the Lithophane, the top inner gets supported but the two in front of it and above it do not, so they get stringy. Probably a setting I am missing or not aware of, but annoying overall, especially since its 6 hours to print only to find out it didn’t support what I want supported.
Have you tried enabling arachne? I remember in the z banding thread that being one of the settings that illuminated zbanding for people. PETG runs hotter so I don’t know if maybe they plays into it. Polymaker makes a filament to use in the support interface that runs at the same temp as pla.
I remember seeing arachne, but don’t remember where. The odd thing is, its 360* when it happens, and JUST that layer. All following layers are back to the origin layer. I’ve been using both heads for these to save time and filament, so going to move both to one AMS and see if it repeats. Using SunLu PETG with Bambu PLA, and the PETG-HF Bambu setting, which works quite well with the SunLu PETG.
I’m using Sunlu PETG right now with Bambu settings and it does work great. Interestingly the Sunlu Grey PETG is the exact same color as the Bambu Dark Grey I ran out of and was out of stock online so I ordered Sunlu PETG from Amazon.
I just printed a tall PETG object and I was quite happy with the smoothness of the walls. I slowed down the print a bit but I did not swap to other filaments.
What happens to that print if you print all if it in one filament type? Is it because of different filaments or is it because of filament swaps.
If I don’t use supports it prints clean top to bottom. I can see the flaws in the purge tower with each head change. Going to try it again with just one nozzle and see what happens. It only needs support for the very top or it gets stringy.
When printing PLA with PETG support, but also the other way around.
The layers where support is introduced, is showing Z-banding.
I am wondering if the different nozzle temperatures, are causing this behavior.
PETG has a substantial higher nozzle temperature.
Maybe there is some temperature compensation algorithm in the H2D that is causing this.
When time allows, I will try some tests with bringing those temperatures closer to each other to see if that influences the behavior.
I am using tweaked material profiles for the support material, to align the bed temperature with the main material.
That might be of influence also.
Can you elaborate? There is very little time between changes using 2 heads. No different than 2 different PLA applications. I can see it possible using just one head.
I am experiencing this same issue. PLA print, with some PETG supports half way up. There is Z banding just at that layer on the PLA on both the object and prime tower. This is with PLA and PETG on the same nozzle using AMS and a long purge time. The issue is present with arachne on and arachne off (as I’m printing several of these so trying to improve the quality)
I wonder if @hotellonely might be correct. Looking at the slicer, that layer is 10x longer than other layers in my setup. I have a similar z band elsewhere where the print paused due to a roll jamming. I’m new to 3D Printing so I don’t have the experience. Maybe it’s related to the lower PLA layer cooling too much or something. Seems a similar discussion here Banding caused by differences in layer time - #8 by metamorph22
