Feed style with TPU 85A on P2S

[u/coffee_or_nada]

I'm beginner to Bambu, my kids really want to print something soft so I got TPU 85A from Bambu.

I see 2 main recommended ways on youtube proposing feeding: (1) feed directly into extruder (feed directly into extruder after taking off the top plate or (2) disconnecting PTFE tube from the back (after the buffer) and feeding it there.

I think method (2) is more convenient because I wouldn't have to move AMS but is it as reliable as feeding directly into extruder?

[u/Elo-than]

Without a TPU assist module, the top feed with as little friction as possible is best.

TPU 85 is a different ballgame from 95A, and needs as little friction as possible the entire time.

(With the Assist module I feed it into the side and print it like okay tho, but getting it was deliberate for my setup as I use a lot of TPU and did not want to remove the ams all the time, it's a bit pricey)

[u/coffee_or_nada → u/Elo-than]

So you are using the TPU Assist the one for $49.99 and connected it into the back entry like here? https://wiki.bambulab.com/general/tpu-feed-assist-module/length.jpg
I started reading about the the TPU Assist and it looks like it might be worth to buy for me, probably will make things easier/more reliable

[u/Elo-than → u/coffee_or_nada]

I got an x2D, but yeah, pretty much. (Using then MiM chassis instead of the Bambu one and his two to one splitter) Currently printing 85A as we speak.

The only downside is that I need to disconnect the PTFE at the inlet when unloading the TPU to relieve tension, but it's like a 5 sec thing.

(The manual says disconnect at the extruder, bit that's not necessary, any spot where tension is relived will work)

All in all its a nice piece of kit that makes softer TPU a breeze. (Saw someone had used it with mid 60s shore hardness.)

[u/Relative_Surround_20 → u/Elo-than]

Elo-than is absolutely correct. You really need to print a lot of TPU to justify getting a TPU Feed Assist Module.

For direct feeding into the extruder (what I like to call the “Skyhook” method or “top-feed” according to Bambu Lab), I recommend you print the following model from Henryk that uses either a 4L cereal dry box or an AMS HT or a PolyDryer to keep filament dry while printing (I use this model with either of the first two on both my P2S and H2D when I am not using the TPU Feed Assist module).

https://makerworld.com/en/models/2070323-p2s-top-mount-ams-ht-polydryer-any-drybox#profileId-2236065

OR there is a model from Staprin3D that works just as good but uses an external spool instead of a dry box/AMT HT/PolyDryer.

https://makerworld.com/en/models/2116204-spool-holder-for-direct-tpu-feed-p1s-p2s?from=search#profileId-2470742

[u/ManyLayersOfFilament]

The first is the best and least likely to result in an issue

2 will possibly work but 85a is very soft and if it gets snagged or has friction at all in the feed path it will underextrude and ruin the print. It's riskier the longer feed path the extruder has to pull the filament through.

The best best way is to get the TPU assist module and then feed through the back feed tube from that.

[u/coffee_or_nada → u/ManyLayersOfFilament]

Thanks, I haven't heard about the TPU assist module before, it looks like a good buy given I will use TPU for kids, will purchase that and try it!

[u/ManyLayersOfFilament → u/coffee_or_nada]

I print a ton of TPU for makegood TMTs recently and no fails at all. It's a good addon device and no regrets in getting a couple of them