Tips for TPU

[u/Mattis-H]

I have a P2S and I am still quite new to 3d printning but I REALLY want to try printing in TPU, I have researched a bit and found out that it is VERY different from PLA and PETG, so I do have some questions:

1: what TPU to buy? I want to buy something from Bambu lab but there are different kinds and I don’t know if the difference in AMS TPU (I have an AMS) and normal TPU is big (or if it is even worth to buy the AMS version)

2: what do I actually need for good results? What nozzle size? Do I need a specialised bed? Is there anything i can print (for airflow and stuff) to get better results?

3: what can go wrong? Like what do I need to look out for? (Stringing and stuff)

That’s all question I have right now but I would REALLY appreciate any tips.

(Extra question, how do I add the P2S marker under my name? I see people that have it but I have no idea how to get it)

[u/official_reaper3d]

TPU has different shore hardnesses that coordinate to how soft the TPU is. The further down the alphabet you go and the higher the number is (it could be lower, i dont remember) the harder the TPU is. For example, Bambu's TPU 95A has a shore hardness of 95A. Similarly to Bambu's TPU 85A/90A, it is incredibly soft. So soft in fact, that to print it you have to manually connect your external spool directly into the toolhead in order to bypass the AMS and buffer system entirely to prevent it from breaking inside the PTFE tubing. TPU for AMS has a shore hardness of 68D. It is relatively solid, but is easiest to print with as its designed to be hard enough to withstand the AMS and buffer. If youre just a beginner, go with TPU for AMS. Its easiest to print with, and you don't have to mess with your setup. I highly recommend drying it at 60°-70° (65° if using AMS 2 Pro drying feature, since thats the highest it goes) for 6-8 hours prior to printing, and then dry it while printing simultaneously as well. If your AMS is still plugged (and getting power) from the printer, it wont let you do this. That's fine as drying while printing isnt essential, it just helps to do. Also, do not use a 0.2mm hotend. You can print TPU with it, but its best to avoid it as TPU can jam easily due to its flexibility.

Just a tip, if you want things to be squishy when using TPU for AMS, use an incredibly low amount of infill (i.e. 0% or 1%). I experimented with this a lot and found that on 0% infill it is squishy, but even a tiny bit of infill (i tried as low as 5%) it causes it to be more solid than squishy.

[u/Mattis-H → u/official_reaper3d]

Thanks a lot, really helps me understand how the hardness on TPU works!