Jamming when extruding TPU
Hello,
I was hoping to tackle the problem by myself but after hours of troubleshooting, disassembling and reassembling the extruder and lots of frustration, I hope that someone here might be able to help me get this printer to extrude TPU reliably again.
For the longest time I never had any problems with TPU and in fact it was my favorite material to print since the results were really clean and string-free but the problems started over night. I was using the standard Generic TPU Settings from Prusa Slicer, with adjustments on retraction. I retracted as far as 4mm without any problems and as mentioned before the prints were super clean. I am using the TIANSE TPU which has always been good to me. 210C on the nozzle, 50C on the bed.
Right now, I can handle small print jobs < 1h, but as soon as I start something bigger the print will fail about 2-3hours into the print job. The TPU is jamming, the extruder is clicking and the stuff gets squeezed out of the sides. Apparently a classic TPU scenario, which I have never experienced before. As soon as I pull the jammed TPU and feed it back into the extruder, I can go on printing again.
Here is what I did so far:
- Switched nozzle
- Switched PTFE Tube
- Tried different tensioner settings
- Cleaned hotend and fans from dust and debris
- Played around with Live Z
- Realigned the extrusion gears
- Multiple cold-pulls
Other materials are extruding fine, I just didnt had the chance to try another TPU Brand, just a new roll which gave the same results. I dont get any bubbles or popping sounds when extruding and I leave my filaments in a wood closet which usually keeps them dry quiet well. As I said I`ve been printing for months now without changing anything and now all my bigger TPU projects are failing.
I know, the topic has been discussed many times but I tried all solutions I came across. Hope somebody can push me in the right direction.
Cheers!
RE: Jamming when extruding TPU
Hello!
I have the same problem. My MK3S+ printed tpu really good for a long time and then this happened. The extruder starts to click after about 2 hours. I had to disassemble the extruder after every jam and it has done this to three prints now.
RE: Jamming when extruding TPU
Well for me it was a culmination of problems. First my bed sheet was completely worn which was why I had adhesive issues. Then I noticed that the axle in the feeding gear was not properly placed so the gear was a bit misaligned. I also printed a little extra piece that would sit just between the Teflon tube and the gears so the filament can’t be squeezed out. Also I started to dry my filaments. It’s really hard to tell what it really was at this point but fixing all of those things gave me much better results and I didn’t had any failed prints in a long time now.
RE: Jamming when extruding TPU
Do you happen to have the print file for the extra piece you made? I am having the same issue on my mk3s+ and cannot for the life of me find any solution. I've read that sometimes the stock heatend can come bent from prusa so I've gone ahead and ordered a bew one but if I can try a 3D printed piece first, I'd rather try that. My tpu prints come out flawlessly when it works.
RE:
For me the key parameter is the room temperature. For TPU I fully open the enclosure on all sides and ensure that the room is as cool as available.
I try to give answers to the best of my ability, but I am not a 3D printing pro by any means, and anything you do you do at your own risk. BTW: I have no food for…