For TPU filaments that cannot be printed with AMS, place the dried filament into a sealed box with a roller axle and insert a fresh desiccant. Then, lock the box to prevent the filament from absorbing moisture during printing. The roller axle helps reduce feeding resistance and prevent feeding abnormalities caused by excessive resistance.
According to the AMS information, ALL TPU is incompatible with it, and as stated in their instructions, TPU is advised to be printed in a sealed container.
So what storage/sealed boxes do you use for printing TPU?
Bit off topic but the Bambu wiki says that 55D and 77D tpu can be printed in the AMS TPU printing guide | Bambu Lab Wiki . But I store my tpu in a large sealable plastic bag with some desiccant
I regularly print on the external with zero issue even after a day exposed. Moisture does creep in but honestly unless you’re living on the equator it is a bit of overkill. Dry your TPU before first use, seal it in a container, take it out and print, dry and seal up afterwards.
I respectfully disagree.
I have one, by Siratech that sucks water out of rocks. The stuff is nearly unprintable with just a little moisture. Had to dry it for a day and a half, printed then sealed and still had issues when I pulled it out again. When it’s bone dry it’s fine, but watch out if it isn’t.
However I’ve found Bambu TPU to behave like you’re describing. Guess it’s all in the brand?
To answer the op question, I use a Sunlu S4 for drying and storage of TPU I use frequetly.
I have had a no-brand TPU that sucked but never at PA level, I recognise it only takes a few grams of moisture to cause defects so admit my response may not fit all cases. I’ve currently had a spool of both the no-brand and a bambu out for a week, the NB is popping so I’ve sent it to the dryer.
On the subject of S4, I love mine but am not entirely certain its sealed enough to be a storage device. The lid is a letdown, flimsy and no seal, it probably serves to release the condensation but once idle it’s just a box and the desiccant won’t keep it low for long.
I agree. That lack of true seal is why I keep mine in that “maintain” mode. I keep my most used filaments in it. 2 colors ABS a TPU and 1 ASA. You’re very right though.
With that siraya tech TPU I thougth I was losing my mind. Couldn’t get it our of a .6 nozzle. Dried for 8hrs and it improved to the point where it would pop but any layers were impossible. Contacted them and they sent another spool, that got lost so they sent another. Ended up with 3 spools, but it does print well after drying forever. Made a pair of crocs just to see, came out pretty good.
I do a double whammy dry, 6hr in the S4 and pop it in a vacuum pot hot with a big desiccant pod for a few hours @-1Bar. Drier than a dingos nether regions so they say…
thank you everyone for the input! I am still open to more suggestions but am going to look into the Sunlu branded stuff and the Creality Space Pi for the time being.
You’re quoting more out of the printing guide than it says. It says 55D and up can be printed. It says nothing about using the AMS. BL states TPU should NOT be used in an AMS. That’s why there’s an external spool holder.
Besides, my feeling about TPU rated with the Shore D scale indicates the filament is worthless for flexibility. A typical golf ball is rated at 50 D. Unless the maker rates the filament with the Shore A scale, they are pulling the wool over your eyes.
Edit: Upon a new review, it looks like BL has updated the printing guide and DOES allow TPU of golf ball hardness to be used in the AMS.
Yeah my point was more of just saying that it is technically possible to print tpu from the ams not that it’s going to be like normal tpu flexibility
If you are not in a humid climate, you may be able to print using the external spool holder ( in the open ). I use TPU only occasionally and have been doing that without any problem.
For storage though, unlike PLA that can be left in the open for a while in my area, TPU should be stored in a sealed bag or container to prevent moisture getting in.
Sometimes it’s humid here (South Texas) and sometimes not. My central air typically runs 10-11 months out of the year. We pick strawberries in February or March. I use my external spool holder with TPU. I store all my filaments in sealed “cereal” containers with desiccant. I also have humidistats in each one.
I usually pull my filament out of the cereal container and mount it. I haven’t found it necessary to dry the Sunlu filament I buy. I unwrap it and put it in a sealed container. I have two Creality Space Pi filament dryers I use for other filament or as “maintenance” if I’ve had a long print on the external spool.
Just the orange type, my thoughts are that the vacuum boils the moisture out but it essentially has nowhere to go so hopefully the desiccant is more absorbent than the filament and transfers that way. No hard evidence but science-like lol.
A terrible accident happened today, a thought struck me.
I wish someone with attention to detail and the ability to record data (i.e. not me) would mesure RH in fresh opened filament from different brands with different spools.
How much moisture does a spool hold. Does PLA really need to be vaccum packed?
Could be eye opening. Could help illustrate to new users the importance of drying, or maybe the importance of just using smart storage. Could be a waste of time.
A few of us are doing measurements, and occasionally post results, but, TBH, in terms of public service announcement, I don’t think it has changed even one person’s mind about anything. People just aren’t interested in facts, or even curious enough to ask relevant questions. I’m at a loss to explain the rampant lack of interest, but so it is, or so it seems to be. I and a few others here are exploring what seems like it will be a very good solution, but it takes time to develop. I’m glad we have at least the few of us to bounce ideas off-of and cross-reference our findings as a check. I’m grateful we have at least that much going in parallel.
One thing I’ll mention is that the cardboard spools seem to hold a lot of moisture. There is debate about whether this matters or not. Eventually I’ll re-spool and be in a better position to evaluate. However, I think it is bad in this sense: most of the consumer grade filament dryers lack an adequate way to expunge moisture from their drying chamber, and, in combination with fixed duration drying (not a good idea, but common anyway) I think it’s obvious that cardboard spools greatly exacerbate this problem and undermine the drying attempts of a lot of people. Probably most drying times are prescribed on the assumption that there isn’t a cardboard spool involved. If there is, then drying times, with most machines, will need to increase, probably by a lot–maybe even by 10x, based on piecemeal data I’ve collected so far. Is it safe to subject a filament to that much longer drying time? Well, maybe not, in which case it’s an argument in favor of ditching the cardboard spool, which, unfortunately, have become all too common.
). I use TPU only occasionally and have been doing that without any problem.