Hi everyone, I’m having a problem printing TPU 95HF on my P1S (actually, on both of my P1S printers). I’m using the official Bambu printing profile with a 0.4 nozzle. The print lasts about 40 hours (but it also happens with 20-hour prints), and at the end, I find the hotend and extruder completely clogged with this white powder (see photo). This occurs both when I have the PTFE tube installed (so the spool on the rear support) and without the PTFE tube (feeding the printer from above with a system I built myself). The filaments are dried for 8 hours as indicated (sometimes even longer). The prints come out very poorly, with inconsistent layers, always around 3/4 of the way through the print, as if there were underextrusion due to the powder clogging everything.
Has this happened to anyone else? What could be causing the problem? Any solutions? Thanks so much to everyone!
What is the filament colour?
Hi @JayZay , the color of the filament is black 
Ok… my first thought was some grinding, but you clarified it.
So, both printers have the same issue → filament is the cause.
Long prints with TPU are prone to bad results as time passes due to TPU’s love for air moisture.
Additionally, long printing times may outcome excessive printing temperatures.
You can try redrying the filament and then print it with the filament in a hermetic box, reducing the chance of moisture absorption over the printing time.
Hi, the first few times I printed directly from the dryer, but the white powder still formed.
I believe it is some sort of coating of the filament or a treatment applied during the production of the filament.
Now I’m trying to find the limit of the maximum print time before the machine clogs.
I initially thought it was grinding, but now I see it’s the filament
Same thing here with a H2D, white and black TPU HF produce white powder, clogging my nozzle hotend and triggering the anormal extrusion error. Our TPU-HF are dried at 65c (12h) then maintained at 45-50c in the AMS HT during prints (6h to 11h of print duration). Same for our H2S.
If it helps, I solved the problem by using Elegoo’s TPU 95A (the basic one). I can print at almost the same speed. The quality is slightly lower, but it’s still fine for my purposes.
I print for 24 and 16 hours alternately without ever touching the printer.
I remove the extruder once a week for maintenance, but I could skip it.
that’s pretty common for low quality tpu and petg. unfortunately filament issue, not printer issue.
However, it’s a filament produced (or simply branded) by Bambulab itself, and it would be sufficient to point out the possibility of running into this problem after a certain number of prints (I doubt they’ve ever had this happen during their tests). Not to mention that it costs €35/kg…