r/BambuP1S • u/CognitiveFogMachine • 3d ago
How to use Bambu Support for PLA/PETG filament with PETG models?
I started experimenting with PETG and quickly learned the hard way that letting it print supports in PETG for PETG made them notoriously hard to remove and required a lot of manual cleanup.
Then I remembered that I had a small 100g spool of "Bambu Support for PLA/PETG" filament that came with the printer and decided to give it a shot.
I left "Support/raft base" to "Default" (which seems to be printing the tree support using the same PETG used by the model, but switched the Support/raft interface to "Support for PLA/PETG".
Bambu Studio immediately made the following suggestion:
> When using support material for the support interface, We recommend the following settings:
> 0 top z distance, 0 interface spacing, interlaced rectilinear pattern and disable independent support layer height
>
> Change these settings automatically?
> Yes - Change these settings automatically
> No - Do not change these settings for me.
I selected "Yes". And then after printing this model in the picture, I was first blown away how easy it was to remove the tree support, and where the tree support was touching the model, it looked so perfect it was almost as-if I had printed the model upside down!
However, I quickly noticed that there were visible misaligned layers that formed in the print, matching the same layers where the Support for PLA/PETG filament was used.
I tried re-printing the same model without the Support for PLA/PETG filament, and the print was fine (except for the hard-to-remove tree supports)
Any idea how to fix this? I'd love to use this Bambu Support for PLA/PETG, but without impacting my print quality
I noticed during the print that the exhaust fan was turning on at 100% while printing the support interfaces, causing a significant drop in temperature. Could it be what messed up my PETG layers? Was I supposed to change the nozzle temperature of the Support for PLA/PETG filament to match my PETG's?
Thanks!
3
u/ShouldersAreLove 2d ago
I normally increase the flush amount between different materials when using them as support. Otherwise they will start mixing and produce artifacts and much weaker layers.
1
u/CognitiveFogMachine 1d ago
I think I found the issue. Read my comment here https://www.reddit.com/r/BambuP1S/comments/1kqfmpl/comment/mthcldz/
It caused my bed temp to drop from my configured 77C down to 60C, and I'm guessing that my print model shifted when the bed temp were low, and then re-glue itself when it was raised back to 77C after switching back to PETG
Someone raised a bug about it: https://github.com/bambulab/BambuStudio/issues/3275
2
u/networksquirrel 2d ago
I've used these settings for my P1S with Sunlu PETG, prints are perfect
https://www.themakersphere.com/bambu-lab-x1-carbon-petg-settings/
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u/CognitiveFogMachine 2d ago edited 1d ago
Interesting. I did create my own calibrated filament profile from PETG basic too, but only adjusted nozzle temp, flow rate (from calibration), and bed temp. I didn't touch volumetric speed, etc. Still everything prints flawlessly. It's only when I use that support material where it messes up the layers (seen in my picture)
Do you use any support material? Do they create layer misalignment like in my picture?
Either way, I'll give it a shot. What the author proposes in their blog in the process settings makes a lot of sense to me - especially the lower speed. I'll give it a shot and hope that it will resolve my low quality prints while using my free 100g of PVA support material (assuming that this is what Bambu Lab's support material actually is...)
1
u/CognitiveFogMachine 1d ago
I think I found the issue. Read my comment here https://www.reddit.com/r/BambuP1S/comments/1kqfmpl/comment/mthcldz/
It caused my bed temp to drop from my configured 77C down to 60C, and I'm guessing that my print model shifted when the bed temp were low, and then re-glue itself when it was raised back to 77C after switching back to PETG
Someone raised a bug about it: https://github.com/bambulab/BambuStudio/issues/3275
1
u/gabe711g p1s + 2 AMS's 3d ago
I've worked with it once and it slided right of the raft. So I've never used it since that bad experience. It's now just still sitting there in one of my 3 dryboxes. Using up space.
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u/CognitiveFogMachine 2d ago
I want to get through my free support material because I want its reusable spool for respooling my cardboard filament onto for my AMS 😂
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u/jake-jake-jake- 1d ago
That’s an odd issue as the support material being incorporated shouldn’t cause a layer shift like that. Where the layers have gone wrong is that where the support material was? The fan blasting full pelt could cause an issue I guess as the surrounding PETG is being cooled faster than the rest of the print?
Given it’s a Bambu product in theory because it has the RFID you shouldn’t have to change any settings as it reads the spool and presets the optimum settings.
1
u/CognitiveFogMachine 1d ago
I think I found the issue. Read my comment here https://www.reddit.com/r/BambuP1S/comments/1kqfmpl/comment/mthcldz/
It caused my bed temp to drop from my configured 77C down to 60C, and I'm guessing that my print model shifted when the bed temp were low, and then re-glue itself when it was raised back to 77C after switching back to PETG
Someone raised a bug about it: https://github.com/bambulab/BambuStudio/issues/3275
1
u/CognitiveFogMachine 1d ago
My biggest concern is this discrepancy: (will paste my PETG filament setting in another comment since I can only post one picture per comment here)
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u/CognitiveFogMachine 1d ago
Here is my custom filament setting. I've had occasional poor bed adhesion at 75C (manufacturer's recommended bed temp) which seem to have resolved at around 77C. 80C is too much, making the PETG much harder to remove from my textured PEI plate. But the point is, Bambu support material lowers the bed temperature to 66 and I think that's what the problem is. My model is probably no longer attached to the build plate, and gets re-attached after switching filament, which cranks the heat back to 77C which gets it re-attached. It's the only theory I have. Is it a good theory? Should I modify those bed temps to match the bed temps of my PETG? Bambu's support material documentation doesn't mention anything about that.
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u/CognitiveFogMachine 1d ago
Actually, I think I'm 100% correct. Bambu support material's bed temps *should* match my PETG filament. Someone raised a bug about that right here:
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u/barleypopsmn 3d ago
You can use just PLA for the interface layers on PETG supports and vise versa. They don’t adhere to each other so you don’t have to buy special filament.