Does anyone know what may be causing my tire print to fail in this way? This happened twice in a row. The flat parts went fine with this same spool, and the straps were successful with a different spool. I have been using the generic TPU setting in Bambu and the filament is in the dryer while it prints after having been dried yesterday. Does this seem likely to be related to moisture or does it seem more like settings?
I have a third try going right now with slower print speeds (30mm/s) and retraction off.
It’s probably underextrusion. I know it’s recommended to print TPU from the dryer but this is what happens to me when I try that, because the tubing from the dryer to the printer causes too much friction.
So I will dry it for a few hours, but then I take it out and feed it directly into the printer after that.
Technically, you don’t have to use PTFE with TPU. I do but it’s a short run with very gentle curves. I use a Creality dryer and it pulls directly from that. Also, if you are using Sunlu TPU the Bambu settings work better.
I have a very long piece of tube AND a y-splitter to another tube, so this seems pretty likely. So I’m going to try it on the regular spool first and then if that goes well I’ll try again in the dryer. Thanks!
Yeah, almost certainly friction from the journey the TPU is taking to the nozzle.
Bambu actually just realised a hardware kit to make printing from TPU easier : link
This is really interesting, because the external spool on the P1S is really not great, especially with the AMS hub on, colliding with it. I should try something like this
This is my setup on my A1, I use a large enclosure to mitigate drafts and mice in my basement. I monitor Temp ( op temp on A1 is like 86 F ) I have a small dehumidifier in the enclosure which works surprisingly well. I use a string to keep the tubes from rubbing on the spool. I have 4 cameras monitoring everything from different angles. With one watching the spool. I’ve only had TPU fail due to it getting snagged overnight. I’ve fixed that from happening.
I have those same Yoopai enclosures for my Sovols. I love them! I hardly ever zip them closed but when printing PETG I keep the flap down so I can keep the room cooler without getting warping due to drafts. And the lighting is a game changer.
Success! It finished and came out really nice with the spool on the regular external spool holder. I want to work on a more efficient setup but at least I have confirmed that underextrusion was the problem, and was able to get a quality part! Thanks for the advice, everyone!
Later on, I bought a dryer and connected directly to the printer so that it would dry while printing. Then I had AGAIN the same problem, underextrusion. That because the spool couldn’t spin freely inside the dryer.
Then I actually designed a holder with bearings to be used inside the dryer, but didn’t have time to post it to Maker World yet…
i had many of these fail. My only solution want to crazy as it sounds lay the spool on the floor and then pull it off the spool little by little. But here is the deal I only had this amount of issues with roll #5 of TPU. Some of the more expensive ones had no issues. I tried in the dryer and on a holder and on everything. But finally just gave my kid $3 to check and pull the tpu off the spool and let it hand about a foot long at an alarm every 20 mins.
