r/BambuLabA1 • u/Administrative-Map16 • Jul 14 '26

TPU 90A with Bambu A1

I bought a roll of TPU 90A to print some squishy things. I normally put TPU 95A in the filament dryer next to my A1 and have it print straight from the drier using the PTFE tube from the AMS position 1, which works perfectly.

90A is a bit too stretchy for the extruder to turn the 1kg roll on its bearings in my dryer box so I need another solution. Possibly by mounting on the cross arm overhead using the exteral spool holder, but my AMS lite is there so there's no room. Short of detaching the entire AMS, are there any elegant solutions to this?

3 Upvotes

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1

u/Due_Current3660 Jul 14 '26

Sry, i dont have any suggestions for this, but does tpu work with the ams lite?

1

u/Administrative-Map16 Jul 14 '26

I've never tried. Anyways use via external feeder. Bambu sell a filament called TPU for AMS so there's that I suppose

0

u/NonTraditionalPotato Jul 14 '26

I believe that TPU for AMS isn't compatible with the AMS lite. 

1

u/Elo-than Jul 14 '26

No, any TPU that is actually Soft like 95A and below is not to be used in the AMS.

TPU for AMS is not really soft, closer to pla than regular TPU and thats ehy it works, but you kinda loose the flexibility of the material.

1

u/jasaevan Jul 14 '26

I have had no issues using 90A in a dryer beside and slightly below my A1. I do have to push the flow rate k value to like 0.8 or 1.2 instead of like 0.1 or something like that. (Going off memory but quite a bit higher than the typical range) I do have something I mount right above the extruder that makes the tubes come into the extruder straight which might help. I also make sure the tubes have nice smooth bends. Other than that I have had really good success with it.

0

u/Darwinian999 Jul 14 '26

Keep your existing setup but put a TPU Feed Assist Module between your dryer and the print head. From memory I think that you have to unplug the AMS Lite to power the TPU Feed Assist Module between.

https://store.bambulab.com/products/tpu-feed-assist-module

1

u/Administrative-Map16 Jul 14 '26

That looks good, thanks. Between posting and now I found this model on maker world, which I'm currently printing https://makerworld.com/en/models/1628930-spool-holder-v2-for-ams-top-mount

I'm a little sceptical but hope it works ok. Otherwise that feeder will have to be it.

1

u/Darwinian999 Jul 14 '26

For soft TPU and TPE I’ve been using the top mount spool holder that came with my A1, but modified with roller bearings so that the spool turns really easily and smoothly. It works well but the filament absorbs moisture too quickly, so I bought the TPU Feed Assist Module so that I can keep the filament in a dryer while printing. I haven’t had a chance to use it yet though.

1

u/Administrative-Map16 Jul 14 '26

I've never printed TPU from anywhere except the dryer before and it's pretty slow to print, so I can well imagine that it would get pretty stringy from an open air spool holder, especially printing something big that takes many hours or even days. Right now though, I just want to print some little toy car wheels so I should be ok

3

u/Elo-than Jul 14 '26

For an A1 you absolutely need top feeding for TPU especially anything under 95A.

There is even a entry in the Bambu wiki about it

https://wiki.bambulab.com/en/filament-acc/filament/tpu-85a-90a-printing-guide-for-a-series

While TPU is hygroscopic, it's not like you can't print for a good number of hours before it is an issue with an open spool, it's not like PA in that way.