TPU isn't moving in or out, help
Hi, I wanted to experiment printing a phone case with TPU (amazon basic white). I used prusaslicer with amazon basic tpu material selected. The mini didn't have a TPU setting to loading the filament so I used PETG and adjusted the temperatures after the print started. The print went fine until the filament bursted out of the extruder viewing hole above. I haven't noticed that on time, so a lot of filament got out of (and ended back in) the extruder. I unloaded the filement (many times) until the loop of filament disappeared and rolled back with some help. However, the end of the filament is still stuck in the hot end. Unloading filament doesn't retract it, and purging does nothing, except some smell. How do I get out of this predicament? and how to avoid getting there again?
RE: TPU isn't moving in or out, help
The mini has a filament selection option called Flex at the bottom of the menu. You just need to follow the steps in this guide, mainly 5-7 to clean the hotend out. It should be quick and easy to fix as long as nothing else is messed up. https://help.prusa3d.com/guide/how-to-replace-a-hotend-ptfe-tube-mini-mini_119449
RE: TPU isn't moving in or out, help
For future reference, the hot end didn't have any left overs to be cleaned in this case. I took apart the extruder and the filament got stuck out of the gear there. It was easy to remove and put the extruder back together.
I should note that I still haven't found a way to print TPU without it getting stuck mid print, even with the FLEX setting for filament in the printer.
RE: TPU isn't moving in or out, help
You can try adjusting the filament tension screw on the extruder, and check your retraction settings in the slicer. Ive only had a problem printing tpu once before, and it was from retracting the filament causing it to be stuck similar to yours.
RE:
I was managed to get past this issue and print successfully by doing 2 things.
1) Really dry the filament, in oven and then in a dehumidifier I bought, until it got down (from above 60%) to roughly 20% humidity. It took more than a day to dry.
2) I used amazonbasic TPU (which is the filament I used) filament settings in prusaslicer.