TPU - multi-material and left nozzle question

Bambu Lab H2 Series Bambu Lab H2C
1

Hi All, I recently printed a model that combined TPU and PETG-CF. I loaded the TPU from the AMS-HT’s back port and ran it through the left nozzle normally through the back. It would only let me choose Bambu lab TPU. That seemed to work fine. In the latest Babmu Studio, I chose the filaments per their respective nozzles and loaded the filament profiles. Because TPU runs much slower, I adjusted that models print speeds. The problem with this is Bambu Studio wouldn’t let me slice it. Some online research led to a workaround where I would have to load the filament profile for PLA on the left nozzle. That printed, but the stringing wasn’t great. For this use case, it worked.

I have a couple of questions.

  1. With the latest firmware that was supposed to allow printing from the left nozzle, why can’t I choose a generic filament vs Bambu branded?
  2. Is multi-material printing with TPU not allowed on Bambu Studio? Is there a fix or perhaps a workaround using Orca slicer?

Does anyone have any best practices to share?

Thank you.

2

It definitely is allowed, I’ve done it many times on my H2C.

3

How did you do it? Because as soon as I loaded the TPU filament profile it would not move forward with it.

4

Just lie to it, if you want to get moving today. Create a profile that has all the tpu settings but is type=pla. Tell the ams it’s pla. It’ll let you do it.

5

And end up with jammed TPU everywhere.

The AMS just won’t handle TPU from a mechanical standpoint. No software bypass is going to change that.

6

This was for the left extruder using a single AMS-HT out the back port. So it’s all mechanical and shouldn’t matter. Plus it can dry while printing.

7

I only dare to load TPU 95A to the right (induction / motionless) nozzle using the TPU Feeder.
As per Bambu wiki TPU and the left nozzle is not supported yet: H2C Filamant Printing Guide | Bambu Lab Wiki

8

When you use the back port of the AMS, you don’t have to tell the AMS what is in there, as you are running it as an external spool.

For the trick of setting PLA in the slicer, and as the material defined for the external spool, I fully agree.

I guess that is what @Bullocks meant then.

9

Careful with pretending TPU is “PLA” or anything besides TPU to the slicer. If one looks at the machine g-codes, one can see exceptions being made specifically for TPU, and other exceptions for some filaments like PLA or PETG. This can be seen in conditional if/else statements in the code.

One important one is that the printer will skip dynamic flow calibration even if enabled or set to “auto” in the final print options – so make sure that’s disabled manually.

If lying to the slicer, “TPU for AMS” is probably a better type to use.

Which “it” are you referring to here?

“won’t let you” how exactly? Is there an error? The “slice” button grayed out? Did it tell you TPU can’t be used in left nozzle?

Which Studio version specifically?

Cheers,
-Max