Hey y’all! This is my first time printing TPU on my Bambu. I’ve never had this stringing issues on any of my other printers before. Any idea on why this is happening and how to fix it? I am using Overture TPU.
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TPU is HIGLY HYDROCOPIC. If it is moist it strings as hell.
Did you dry it at least 6 hours befor use?
I print Overture TPU 95A 240/35 and created an spezial Print-Profile (what is not really necessary)
Could be wet filament unless you used some non-default settings, but those strings look more like deliberate extrusions or whole lines sticking to the nozzle. Is your nozzle clean? Are you using very low layers (<0.16mm)?
As for drying - even 6 hours @ 55ºC is not always enough for drying as I found yesterday. Mine only started printing really nice after about 10 hours in the drier. If you have drier with a fan the 6 hours could be enough, but I need to open my Sunlu S2 every now and then to vent it.
I never get better TPU results as on the X1C without AMS Down to shore 90A - after this mark I need to change to a other printer.
For English subtitles on a German-language YouTube video, do steps 1 to 3
Watch the following video from 6`27`` with Englisch subtitels for the X1
General Infos
It’s crazy that the 3D Printer industrie don’t yet know about the 4 roller drives. In the beginning of soft aluminum welding only 2 rollers were used as well to push it over 3m… Today, even steel wire are driven at least by 4 rollers and this even on the cheapest machines from the cheapest manufacturers…
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I will definitely give these videos a watch!
It was a brand new spool so that shouldn’t be an issue. I currently have it in my dry box “just in case” the packaging was compromised.
Even than… ALLWAYS dry the filament before use… the plastic-bags are not allways watertight. An the filament can have been moiste before you get it vaccuumed.
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To judge moisture content, I weigh my spools to judge moisture content. It is pretty common for a new spool right out of the vacuum bag to lose 6-8 grams after 12 hours of drying in my X1C.
TPU in particular gobbles up water. I left a spool on the printer overnight, so I dried the partial spool again before putting it back in the bag and found that it lost 2 grams.
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It is absolutely possible to get a wet filament in a sealed bag. In fact I’d say it’s about 50/50 whether you get it really dry 
Also, drybox just keeps it dry, it doesn’t “dry” anything. You need a drier for that.
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I agree. I started FDM printing with Makerbot around 2010. I never dried filament fresh from the bag. It always printed fine. Didn’t do a lot of FDM when I got my Formlabs SLA, so I had a few years go by without buying any new filament. Now I’ve been buying filament again for my X1C, I’ve found more often than not it does need drying, even if it arrives in a vacuum sealed bag.
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I have a theory that filament moisture was still an issue back in the day but we were struggling with so many other issues that it wasn’t very apparent in finished prints.
Now that the hardware/software of printing is really dialed in, the moisture issues are more evident.
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Good to hear, thanks for this info since I don’t know the 3D printing during this time. Well, my TPU doesn’t come from China at all (Soft materials give me even more alarm bells than the hard stuff). So maybe I also see the Flow as the bigger problem as the TPU in my case is always FDA compatible get sealed again with similar bags like I throw stakes into the freezer for 2 years… I once bought a dryer just in case and always asked myself why I never needed the thing… now I probably know why.
Maybe, I love the lidar and the flow calibration for each print - An error which is systematically ruled out.
Add. However, over-extrusion may just be a problem. Since a few minutes Underextrusion has become a very interesting topic to me in order to reach Shore 50A… https://www.youtube.com/watch?v=aQe4NaYw93Q