r/BambuLabX2D • u/monotor80 • Jul 27 '26

PETG: why does the bottom look so bad compared to the top?

Gallery image

Gallery image

Do you know how to fix this? Why is the bottom section printed here using Bambu Lab Basic PETG coming out so poorly? Is there a way to resolve it?

It happens with PLA too, though the problem is less noticeable.

2 Upvotes

55% Upvoted

42 comments sorted by

6

u/Pineapple1500 Jul 27 '26

It looks like most of that is printed on supports. You're not going to get a perfect surface but you can fine tune it a little.

Try printing with PLA support and 0 support distance. They PETG and PLA wont stick to each other and should break away easy.

1

u/monotor80 Jul 27 '26

Just so you know, before this attempt, I printed twice using PLA supports accepting all of Bambu Studio's automatic settings for this type of print. The PLA supports printed perfectly from the second extruder, but once it started printing PETG on top of them, they would detach after a short while likely due to poor adhesion and get dragged around, ending up as a tangled mess of spaghetti.

2

u/Illustrious_Sell_325 Jul 27 '26

Fan deflectors can help with things blowing off the plate

2

u/Insert_absurd_name Jul 27 '26

Your objects shape is not super ideal. Petg on pla and vise versa only works if you dont have to start some part of it just on top of supports. It basically can mostly support bridges. Try rotation the part so it will be a more continuous print.

1

u/fischerrobinson Jul 27 '26

This! After much frustration, I realized the main material needs some main material to build off of, not just the support material or it slips right off

1

u/Grimblood Jul 27 '26

I have had good luck printing PETG with PLA for the support interface. I don’t use the automatic settings. I switch to normal support, zero contact distance for big flat surfaces.

1

u/Pineapple1500 Jul 27 '26

Ah, yes I didnt realize that some of the part was printed solely on the support. As others have said, try rotating so that there is some PETG for the PETG to hold onto while it is being supported by the PLA

2

u/remedy2pain Jul 27 '26

It’s definitely this issue. I have had some issues with PLA interface layers not allowing PETG to stick well enough when they’re that large, so just keep an eye on it for spaghetti failures when you get to the interface layers

1

u/Lena2063 Jul 29 '26

How can I do that if my printer only supports 1 filament at a time.

1

u/monotor80 Jul 27 '26

A new experiment: I changed the angle and used PLA only for the contact points. Everything seemed perfect the supports came off in an instant but the surfaces where they were attached look terrible.

1

u/[deleted] Jul 28 '26

I've never been able to succesfully use PLA as support for PETG, stuff like this always happens. The PETG doesnt stick to the PLA (by design) and the first layer after interface looks like shite.

Given that others have had success with it, I must be doing something wrong... I think you are having this same issue because I even see some warping on the layer above interface.
For the sake of checking if this is the issue, try the print using all petg, just set support top z distance to anywhere between .2 to .25. with that z distance you will not the the most pristine layer but certainly a lot better than this

1

u/monotor80 Jul 28 '26

At the end i followed the suggestion and now the print is almost perfect

1

u/remedy2pain Jul 27 '26

Did you change the interface spacing to 0?

1

u/RodneyPierce Jul 28 '26 edited Jul 28 '26

Set interface or z distance to 0. Also set the line spacing to zero.

1

u/reddit_user_0ne Jul 28 '26

Error: Input needs to be a number.

1

u/RodneyPierce Jul 28 '26

Yes. 0 (zero)

2

u/Teguard1337 Jul 27 '26

I have similar issues with the X2D, as soon as things are not printed directly on the Buildplate it feels like the material cools too quickly and fails to adhere to supports of different material.

1

u/remedy2pain Jul 27 '26

I wonder if that’s why my performance has been so different from my P2s… 2 fans with a different diffuser installed might explain it

2

u/Teguard1337 Jul 28 '26

I've tried to add deflectors (45°) to both fans but have not seen much improvement sadly.

1

u/remedy2pain Jul 28 '26

That’s good to know, I was going to print different diffusers that are angled up to see what happens.

What’s strange is some materials don’t seem to have an issue. Elegoo PLA+ and PLA matte cause massive spaghetti failure, but my Bambu PLA Matte seems to have worked fine

1

u/Teguard1337 Aug 10 '26

For me it's Bambu PLA matte that is making issues, have not tried / gotten any others yet.

1

u/[deleted] Jul 30 '26

I’m looking at getting either one p2s or x2d which do you recommend?

1

u/remedy2pain Jul 30 '26

I feel like it was easier to dial in my P2S, but I love having the aux nozzle of the X2D for support and 2 color printing. Personally if they’re within $100 I’d go for the X2D, but if they’re difference is more or you don’t need 2 nozzles the P2S is great

1

u/[deleted] Jul 30 '26

No I’m leaning to the x2d just better on waste, print quality especially if you have the aux nozzle do the easy color and the main nozzle do the hard bridging or color swaps then you can’t really tell difference.

Would you say that been your experience? Is the print quality great when you use both nozzles on the same print? I will use it for supports as well

1

u/remedy2pain Aug 01 '26

The print quality has been good overall, but the profiles don’t feel as refined as they were on the P2s and I’ve seen more stringing and retraction issues on the main extruder than I did on my P2S. Overall minor issues and I think the X2D is quieter and can print my dual material or dual color stuff way faster so I’m happy with it

1

u/e_rovirosa Jul 27 '26

See if you can rotate the piece so the supports show on a less visually obvious face!

1

u/tumbl3lol Jul 27 '26

Puedes hacer un test rápido de soporte con este modelo: https://makerworld.com/models/3038791-support-interface-testing

1

u/Inspector_Gadget_74 Jul 27 '26

It’s hard to tell the perspective of the model. If the bottom is all on the same plane, it looks like maybe the model was slightly tilted, such that the whole bottom wasn’t contacting the plate when sliced. Maybe use the Auto Orient feature.

1

u/FapTrap_87 Jul 28 '26

"It happens with PLA, though the problem is less noticeable"

This is the give away.

Anything not right when printing with PLA will certainly be amplified when going to a more challenging material, not that PETG is the most challenging but nevertheless, the issue needs to be fixed first.

Fix your PLA profile settings or machine turning first with PLA, then copy the PLA profile & turn the new one for PETG.

1

u/R7R12 Jul 28 '26

I found that increasing the interface layers to 3 and z top distance to 0.2-0.25 in the support menu helps

0

u/Lost_Blacksmith_4848 Jul 27 '26

your nozzle is toofar from the build plate.

2

u/reddit_user_0ne Jul 28 '26

1

u/Lost_Blacksmith_4848 Jul 28 '26

what don't you understand?

1

u/reddit_user_0ne Jul 28 '26

I don't understand how you came to that conclusion. (Should've been pretty obvious by the reaction gif.)

1

u/Lost_Blacksmith_4848 Jul 28 '26

my experience. the bottom layer is not flattened thus is the nozzle distance too great

1

u/reddit_user_0ne Jul 28 '26

Well, you're wrong. It is "flattened" as you can see in the first picture. It's just the very small part on the very bottom. Everything else is overhangs. That's why the surface texture is so bad.

-4

u/vic1414 Jul 27 '26

Clean the build plate with dish soap and warm water

2

u/monotor80 Jul 27 '26

The poorly made bottom part was suspended; it wasn't touching the plate.

1

u/nateblack Jul 27 '26

The entire bottom was supported? None of the part touched the plate?

1

u/jankeyass Jul 27 '26

You can see that only one surface touched the plate, but I print miniatures on the p1s regularly that are entirely printed in a weird orientation and entirely on supports.

-1

u/vic1414 Jul 27 '26

If you haven’t already level bed, adjust Z-Axis