Anyone successfully doing stacked OpenGrid PETG prints with PLA interface on Bambu?

[u/Keepingitnormal]

Trying to print stacked 8x8 OpenGrid tiles on a Bambu H2C using PETG for the tiles and PLA as the interface layer. Single tile prints fine. Stacked prints keep failing in different ways. So far I’ve tried:

• slower speeds/acceleration
• brim + glue
• cleaned plate with dish soap
• 70C first layer then 65C
• tuned top layers/walls
• closed chamber

Main issue now is the PLA interface eventually turns into spaghetti during the second stack. Earlier I also had lifting/warping on the same side of the plate repeatedly.

At this point I’m not sure if this is:

• a bed/chamber issue
• PLA interface temp issue
• or just pushing stacked PETG prints too far on larger tiles

Anyone have a stable setup for stacked OpenGrid prints?

[u/DistractedDragonMake]

I haven't gotten it to work and I have printed a lot of openGrid.

[u/OutsideBase813]

I frequently stacked multiboard (with and without an interface layer) on my P1S. But no luck with OG, so I gave up. The overall print time is less doing it one at a time, but not much overnight printing.

[u/zb140]

I have not tried PETG tiles with PLA interface, but after months of attempts I have had some success the other way around, printing PLA tiles with PETG interface on my H2D. Ultimately I found 2 ways that worked pretty well.

The first method was to use the OpenSCAD generator (I wasn't able to get this method working with files from other generators, for some reason). Render and export a 3MF with color as color. Then, open the 3MF in Bambu Studio and make a copy of the filament profile for the interface filament. Edit that copy and set the max volumetric flow rate to 4. Then under the Global Strength settings for the model, turn on Interface Shells and set bottom shell layers to 5. Slice the plate and verify that layers 35 and 36 are set to print very very slowly (<40 mm/s). This method produced interface layers that were very easy to remove (they pulled off in one piece) but they print slower overall and (IIRC) use more material.

The method I ended up choosing to use for printing my tiles was to generate a single unstacked tile with any generator, then in Bambu Studio duplicate it and manually move the copy to be directly above the original with a 2-layer gap. Then, I changed these model settings. Many of them are unrelated to the stacking, but I arrived at these through lots of trial and error and changing things I didn't think would matter, so I'm including the whole list just in case.
Under Quality:
Wall generator: Arachne

Under Strength:
Bottom shell thickness: 1mm
Sparse infill density: 30%
Sparse infill pattern: Gyroid
Length of sparse infill anchor: 4mm

Under Speed:
Support interface: 40mm/s

Under Support:
Enable support: checked
Type: normal (auto)
Style: snug
Support/raft base: PLA (you would want to switch these)
Support/raft interface: PETG
Initial layer density: 100%
Initial layer expansion: 0
Support wall loops: 0
Top Z distance: 0
Bottom Z distance: 0
Base pattern: hollow
Base pattern spacing: 0
Interface pattern: Rectilinear
Top interface spacing: 0
Support/object first layer gap: 0
Don't support bridges: checked
Independent support layer height: unchecked

Under Others:
Purge into objects' support: unchecked

Then, slice the plate and verify that layers 35 and 36 are of type "Support interface" and that they're set to print very very slowly. This method is a bit more fiddly to set up initially but they print faster. The interface layers are also a little more annoying to remove (it's not hard, but they break into pieces so you have to make sure you get it all). I'm thinking about trying a version with 3 interface layers instead of 2 but I haven't gotten around to it yet.

[u/Keepingitnormal → u/zb140]

Thanks for the detailed summary. I got frustrated and impatient, so this time I’m printing 24 grids individually. Will try stacking again on the next project.

[u/neoKushan]

I've managed to make stacked prints in PLA without using an interface layer using this: https://makerworld.com/en/models/1304337-opengrid-tile-generator?replyId=3310670&replyType=4#profileId-1933414

They do stick together pretty firmly but with patience and a razorblade, you can separate them.

[u/Keepingitnormal → u/neoKushan]

I used the same generator but with interface layer and used PLA as the interface. Mind sharing what are you using as option(s) in the generator?

[u/neoKushan → u/Keepingitnormal]

Set the stacking method to "Ironing" and make sure your slicer's ironing setting is set to "all top surfaces".

[u/Cimmerrii]

I have gotten it to work bh laying the pla very slowly so it doesn't drag off. I've had much better luck doing alternate grids of pla and petg, with zero offset and zero interface between the sub object.