I want to print TPU with my Creality Hi. I encounter the same problem every time: after about 45 minutes, the extruder jams because the TPU wraps around the gears (see photos). It runs perfectly for the first 45 minutes, and then the extruder clogs. Does anyone know why this happens and what I can do about it?
Technical details:
TPU by Geeetech
Nozzle temp.: 220°C
Bed temp.: 40°C
Speed: 15 mm/s
Retraction: 2 mm
Humidity: about 20%
The TPU is fed directly from the spool holder into the printing-head (without a tube); the CFS is not used.
I read the thread ( TPU breaking the extruder - #5 by garin_shaw ), but it seems like it doesn’t work there right from the start. In my case, it works for the first 45 minutes; only after that does the extruder clog up.
the creality hi requires immense tuning to get it printing tpu correctly,check creality cloud for the spring spacer which helps you print tpu abit better by relieving some of the pressure….
Thanks for the tip. I found the spacer in the cloud and will give it a try.
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youre welcome 
…i hope it helps, good luck!
When you say “humidity 20%”, that’s the humidity of your home ?
For TPU, you still have to dry it as much as possible as it loves absorbing humidity.
And just a tip, but instead of controlling the speed, control the “Max volumetric speed” in the material settings.
If you control the printing speed, it may go higher depending of the features it is printing.
Put 2 or 3 mm3/s in “Max volumetric speed” and it limits everything
also dry your filaments.i do all mine,freshly out the packaging
It’s the humidity of the TPU. I store it in a dry box with a gauge.
I will also try the “Max volumetric speed”
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It works! 
I made three changes:
- I set the retraction to “0”; it was previously set to “2”.
- I set the max volumetric speed to 2mm³/s
- I printed the spacers and used the middle one (0.6mm).
The print took just under 3 hours, and I didn’t get any more jams. Great. Thanks for the tip!
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It funny how a new machine cant print TPU and my old Ender 3 with a sprite extruder prints it like a charm.
You’re most welcome buddy..happy printing!
