H2D Trouble with TPU and PLA support

Bambu Lab H2 Series
1

I cannot get the H2D to print TPU with PLA supports. both spools of filament are new, I have tested the model and both spools of filament on my snapmaker J1S and the print comes out flawless. I commonly print this combination without issue on the J1S.

I dialed in each filament with test prints on the H2D and If i print each filament individually the print comes out clean so I don’t think there’s anything wrong with the filament. When I print the two together in the H2D, with TPU and PLA supports, both are poor quality and the PLA will often stop extruding (Air printing detection is on low but doesn’t seem to catch it) . if I stop and manually extrude the PLA it comes out like normal so I don’t think it’s clogged. If the PLA doesn’t stop extruding the print is very thin and crumbly. Project attached and some pics of this test part with PLA\TPU only and together. Whenever both print the quality drops, even when the PLA isn’t printing the TPU quality is still poor so it has to be settings.

Right Extruder: SainSmart TPU on external Spool
Left Extruder: Bambu PLA in AMS Pro

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CameraMount.3mf (100.3 KB)

1 Like
2

try to see if the speed is the same when is printing tpu alone vs tpu and pla together when is printing the TPU because i see is printing fine the PLA in the combo of both

3

You might want to look at the temperature settings of the bed for both filaments. TPU likes a cold bed, while PLA likes something around 55C.

In the printer configuration you can set if you like the bed temperature to be the highest of the 2 or the temperature of the first filament.

You could also consider to print the support also in TPU and only print the interface in PLA.

4

Are you using the default printing profiles or did you customize some settings? I usually never print TPU from the side spool or TPU inlet, I feel like I can get even less resistance by removing the top cover and printing directly from the top of the extruder.

I use this: AMS HT Top Mount for H2D / TPU Bypass Mount by Henryk MakerWorld: Download Free 3D Models

I don’t even use an AMS HT, I use one of the Polymaker Dry Boxes and it works great for the TPU and my PLA supports work as well. I usually dry while I’m printing, seems to me your TPU could be a little drier.

Also wondering if the enclosure is getting a little too hot?

5

Yes I agree it seems like your TPU needs drying. I had a flawless print with TPU and PLA other than I hadnt dried my TPU and there was artifacts on it.

6

I agree with everything above, there is certainly an issue with your TPU, it might be drying but most probably drag between your spool and the extruder.